The road to driving automation – by James Dillon of Technical Topics

Along with the change in motive power sources, from internal combustion to electric motor, automation of driving will rock the axis of our technical world.

There is much jaw-jaw around ADAS and Autonomous vehicles at the moment, and rightly so, but it may have left you feeling a little jaded, hearing about the latest and greatest tool companies’ ADAS calibration equipment. However, the automation of the act of driving a vehicle is big, it’s here, and it will affect you,  your business and the way you work. 

First off, let’s do a bit of jargon busting. Autonomy means a state of self-governing, therefore an autonomous vehicle has the ability to self-govern; that is, it will have the capability to carry out a range of operations without any direct input from the driver. ADAS, or Advanced Driver Assistance Systems, is the banner under which the different elements or sub-systems of the autonomous vehicle are referred to. Common ADAS* (we can’t really say ADAS systems, because the ‘systems’ bit has already been referenced) include: 

Adaptive Cruise Control: Where the host vehicle maintains a commanded speed and, if relevant, a defined distance from the vehicle in front. 

Active Lane Assist: Where the host vehicle will monitor the vehicle’s position in a defined lane and move the steering wheel to maintain that position. 

Adaptive Front Lighting: Where the host vehicle directs the headlight beam in the direction of steerage. 

Autonomous Emergency Braking: Where the host vehicle detects the proximity of surrounding vehicles and automatically applies the brakes to prevent or reduce the effect of a collision. 

Blind Spot Monitoring: Where the host vehicle uses sensors to detect vehicles to its side (blind spot). In conjunction with Steering Assistance Systems, the host vehicle may deliver corrective steering torque to maintain the vehicle’s position to prevent a collision. 

Pedestrian Assist: Where the host vehicle uses sensors to detect pedestrians in the path of the vehicle and automatically brakes to avoid a collision. 

Traffic Sign Recognition: Where the road signs (such as speed limits) are recognised and an appropriate indication or warning is given to the driver. 

*different vehicle manufacturers may use slightly different terminology. We have described the systems in generic terms. 

There are variations in the systems which range from warning the driver if the defined conditions aren’t being met, to active intervention to ensure that the defined conditions are met, and/or collisions are prevented, or their impact is reduced. 

In order to function, these systems make use of several key components and sub-systems; some of these may be new to us, such as Radar and LiDAR, others are adapted mechanical systems with which we will be familiar, such as electronic power steering, and anti-lock braking. Blending these ADAS elements leads us towards autonomous vehicles. 

Levels of autonomy 

There are six defined levels of autonomous vehicles, as set out by the Society of Automotive Engineers. Level 0 – The base level of no automation. Level 1 – Driver Assistance, where the vehicle can assist with tasks such as steering, braking and acceleration. These functions are enabled by the driver and are not automatically applied by the vehicle. Level 2 – Partial Automation. Two or more automated functions work together to relieve the driver of control. Level 3 – Conditional Automation. This is defined as the execution of steering and acceleration/deceleration and the monitoring of the driving environment. Level 4 – High Automation. At this level, the vehicle doesn’t require a driver. The vehicle is capable of all aspects of the control of the vehicle, under certain conditions, and the driver can intervene. Level 5 – Full Automation. This is where the vehicle can perform all aspects of driving under all conditions. 

So how will ADAS affect technicians and independent workshops? Firstly, diagnosing and rectifying system malfunctions. This will bring new components into the technical realm for test and measurement. Diagnosing on- board camera and radar function, for example. Secondly, performing calibration on the systems after other mechanical repairs. If, for instance, the front panel of the vehicle is removed during a timing belt renewal (and the radar mounting is disturbed), the system requires recalibrating. The same is true for any work which affects the steering geometry (track rod ends, ball joints, suspension bush/arm replacement) or the ride height of the vehicle (new shock absorbers, upgrading alloy wheels). The vehicle may have one or both forward and rear facing radars as well as a forward-facing camera. 

There are obvious safety implications of using a vehicle when the base calibration is incorrect. The margins for error are very small. The range of these sensing devices can be up to 300 meters, where a 1 degree sensor alignment error leads to a 5.2 meter focus error (almost the width of three cars) at this distance. This could cause the vehicle to be unable to detect an object until it is much closer, causing a delay in the moment of intervention (Time To Collision), leading to a potential collision. 

Calibration rigs are widely available and are usually accompanied by a suitable scan tool. The scan tool initiates the system’s calibration process and the calibration rig contains the reference targets. Most system calibrations cover both the radar sensor and the camera unit. Validation of the vehicle’s wheel alignment and the mechanical base alignment of the radar(s) and camera sensors is critical prior to any calibration events. Technicians who carry out ADAS calibrations must ensure that the calibration environmental conditions match the vehicle manufacturer’s requirements. They should also be able to demonstrate competence (through an accredited ADAS qualification) and keep appropriate calibration records (evidence of geometry and calibration data). A vehicle with a non or incorrectly calibrated system presents a significant liability for the technician, the repair business, other road users and the driver. 

With the European Union mandating that all vehicles be equipped with autonomous emergency-braking systems, lane keeping, forward-collision warning systems and speed assistance in the next couple of years, the opportunity for workshops is growing rapidly. As always, the key to doing it correctly is learning about it. Technical Topics run accredited ADAS Calibration Training on their Accredited Diagnostic Technician and Master Technician Programmes. See www. for details. 

Big Day Out training is bespoke

Our final Big Day Out training event of 2019 will take place next month at the ZF [pro]Tech training facility in Crick, Northamptonshire, and we’d love to see you there… 

On Saturday 5th October, James Dillon and David Wagstaff of Technical Topics, alongside Andy Crook of GotBoost, will engage, challenge and, almost certainly, entertain technicians and workshop owners from across the UK with their unique form of training. Live faults and scenarios will be presented and the group will analyse live data, working out the best courses of action to get that all-important first-time fix. 


Andy and James are now handing the agenda for the Big Day Out training event over to delegates. 

The trainers will create several mini-workshops and a Q&A session based on feedback from those who have purchased tickets and completed a brief survey. 

Delegates are being asked for examples of diagnostic work they find most challenging, which scan tools they currently use and what vehicles/systems or areas they’d like to see covered. 

Join Autotechnician and the team for some fantastic training, which is heavily subsidised by our Autotech sponsors ACtronics, Delphi Technologies, febi bilstein, Flex Fuel and ZF Aftermarket. 

Join us for our last training event of 2019! 

Our next Big Day Out will take place on Saturday 5th October in Crick, Northamptonshire. Tickets are subsidised by our Autotech 2019 sponsors and are available now for £98+VAT. Email: for details or call 01634 816 165. 

Non-intrusive engine testing – By David Wagstaff of Technical Topics

Back in June, we were pleased to host a very interesting training event here at Technical Topics HQ in Bridgwater. The event was organised by Ryan Colley of Elite Automotive Diagnostics, who had arranged for technical expert Brandon Steckler to fly in from the States to talk about the subject of pressure pulse analysis. 

Brandon’s background is as a Honda dealer technician and his knowledge of pressure pulse analysis came from a personal interest in the subject and the resulting research he undertook. He spoke of spending many hours just staring at waveforms on a computer screen trying to understand what was going on and the relationship between the waveform and gas flow within the engine. His passion for this is obvious as soon as he talks about the subject. 

Although the training was headlined as pressure pulse analysis, it actually covered many aspects of non-intrusive engine condition analysis. He began by starting with using an oscilloscope and an Amps clamp to carry out a relative compression test to look for compression pressure anomalies. This is probably one of the most valuable tests that can be done with an oscilloscope and one that if you are new to scoping, should get to grips with. The process is such a timesaver, allowing a compression test to be carried out in a couple of minutes without the need to remove spark plugs, glow plugs or injectors, and this also avoids the risks of a snapped component. The time saved from this will help to pay for the oscilloscope alone. 

If you have carried out a relative compression test and identified a loss of compression, the next step would be to work out what the cause is. The lost pressure must have gone somewhere. If a valve or the piston rings are not fully sealing, then as the piston moves up the bore, it will push air past them and create a pressure pulse. We can use a pulse sensor such as Pico FirstLook or Autoditex Pressure Pulse Sensor to display a waveform on the oscilloscope screen. These sensors do not measure absolute pressure but instead produce a voltage output as the pressure changes. If the pressure stabilises then the output returns to zero. So, they are measuring change in pressure and not the actual pressure in a system. 

When we carry out a manual cylinder leakage test, we apply pressure to the cylinder from our workshop air supply and listen for the escaping air from the inlet manifold, exhaust or crankcase to tell us where the pressure is leaking from. However, with this test, we crank the engine and use its own generated pressure to find the leak. The pulse sensor is effectively ‘listening’ for the escaping gasses, so we place the sensor in the exhaust, inlet manifold or dipstick tube to trace the fault. 

By adding a cylinder reference, perhaps from an injector or ignition coil, we can even work out which cylinder is at fault, how cool is that? This is completely non-intrusive and within just a few minutes, gives us a firm cause of an internal engine fault. As no mechanical stripping has been undertaken, if the car is beyond economical repair, the customer can drive it away again, meaning no pushing cars out of the workshop with heads removed and being stuck with a disabled car in the car park until the customer decides what they are going to do with it. 

Much more information is contained in the pressure waveforms once you have a good understanding of them. Brandon could, for instance, see issues with valve clearances on a V6 Honda engine by just simply placing a probe into the exhaust on a service and looking at the waveform. If he spotted an issue, he was able to upsell a valve clearance adjustment job, knowing it was required. 

Brandon moved on to talk about in-cylinder pressure waveforms using the Pico WPS500. Although this now involves getting access into the cylinder by removing something like a glow plug or spark plug, it does give us more information about the engine’s mechanical condition. We can now measure actual compression pressure (both cranking and running), see issues with airflow in and out of the cylinder, valve timing and sealing issues, plus any mechanical issues with the valve gear. 

When you get to more complex issues you can combine all the techniques above and display relative compression, in-cylinder pressure and pulse sensor waveforms on the screen together. The information can be overwhelming but there are a few overlay programs that can be used to help work out what is happening in different parts of the screen. 

The event was well received by all those that attended and has created quite a buzz in several online forums. It was so popular that Ryan is likely to invite Brandon back for a second round of training – keep an eye out for more details. 

If you want some more hands-on training, we’ve been running training at Technical Topics covering very similar subject matter for a few years now as part of our ‘Oscilloscope Masterclass’ course. We use our engine test rig to get you deep into engine condition analysis, relative compression tests and pressure waveforms, using both pulse sensors and WPS. We can insert faults on the engine and let you explore the results whilst we guide you, enabling you to build your knowledge of the technique. The next date for this course is Sept 30th, if you’d like more information on the course contents and dates, please check out our website at 

Finally, I’d like to thank Brandon for his very interesting and informative presentation, Ryan Colley for organising this very enjoyable event and Steve Scott from Simply Diagnostics for his support. 

The latest vehicle networking technologies

Familiarise yourself with the latest vehicle networking technologies – By James Dillon – Technical Topics.

CAN Bus was, or maybe still is, considered to be king of the vehicle networks. We have CAN Bus enabled scan tools, CAN breakout boxes, and even CAN enabled LED lighting kits. However, there are several ‘new kids’ on the block – we’ll use the term ‘new’ with a large pinch of salt, but undoubtedly, in-vehicle networking has changed and is continuing to do so. Due to the restrictions of bandwidth (capacity for data) and technological requirements, CAN is losing favour as the chosen one and the vehicle manufacturers are ushering in a new era of vehicle networking technology.

As the electronic systems within a car continue to grow in complexity, we’re seeing more sensors, controls and interfaces being utilised. All of these are leading to much higher bandwidth requirements. The different computers and domains within the vehicle increasingly need to communicate with one another in order to share their data. The complexity, cost, and weight of wiring harnesses to support this, has increased such that the wiring harness is now the third costliest and heaviest component in a car. Currently, there are several different proprietary standards for communication, with each sub-system typically using a dedicated wire/cable/network. 

By moving towards a single standard, all the communications from all the different components can coexist on the same network, with a single pair or wires connecting each location in the car from a central hub or network switch. The increase in volume of data, system participants and speed requirements, mean that CAN isn’t technically able to cope with any longer. 

Figure 1: Flexray Topology

Flexray is one of the newer standards used for inter-module communication. We’ll get into the technical nitty gritty a bit later in this article, but the headline is that Flexray runs at 20 times the speed of a typical CAN network. This speed improvement is due to distinct structural differences in the Flexray network layout, as well as enhancements to signalling and software control techniques. The improved signal speed that provides the extra bandwidth is so quick, that many automotive scopes will have a problem measuring it. The bit time in this system is measured in nano-seconds (billionths of a second), compares to CAN’s micro-second bit time (millionths of a second). In practical terms, many automotive oscilloscopes are simply incapable, because of a lack of scoping horsepower, to measure signals at this speed. 

Figure 2 a: CAN & Flexray loom

Unfortunately, this will leave technicians in the dark, being unable to see signal structure, which will delay diagnosis and potentially lead to misdiagnosis in vehicles which utilise the Flexray network infrastructure. In order to provide some clarity, I’ll do my best to answer some of the questions that surround diagnosis of this system.


Just how widespread is the use of Flexray? If we consider the group (known as a consortium) who were involved with developing the Flexray standard, it included Bosch, Phillips, Freescale, NXP Semiconductors, BMW, VW Group, Daimler, General Motors, Ford, Mazda, Fiat, Toyota, Honda, Nissan, PSA, Renault, Volvo. Flexray is currently fitted to a wide range of vehicles, which include BMW (1, 3, 5, 7, X3 and X5 Series), Audi (A4, A5, A6, A7, A8, Q7 and TT), Mercedes (C, S and E Class), Land Rover (various) and Volvo (various).

Figure 2 b: Flexray at ECU

So how do you tell if the vehicle has Flexray? The issue with identifying Flexray from ‘under the bonnet’ is that the physical layer (for our purposes, the wiring) looks the same as CAN. It is difficult to know without consulting technical manuals or wiring diagram information for the specific vehicle in question. Also, many Flexray equipped vehicles still utilise CAN, Flexray, LIN and MOST networks on many of the sub-systems. For instance, both Audi and BMW have a combination of CAN and Flexray within the powertrain system. Telling them apart without technical information is almost impossible. This means that a vehicle which is suffering from a fault many not display useful or useable test or data values. 

Figure 3 a: Diagnostic CAN Terminals

How can I test Flexray? Can I use the ohmmeter across the data link connector like I do with CAN? In truth, using the ohmmeter across the datalink connector has always been a very slack method of testing CAN. This is due to the implementation of diagnostic interfaces (firewalls or gateways) which separate the actual CAN from a diagnostic version of CAN. In systems which use this technique, the data link connector uses a ‘simulated’ 60 Ohm resistor between the data link connector and the gateway. In this case, the CAN proper (the vehicle side of the diagnostic interface) could be shorted to ground, having no communication, but your test at the data link connector will show a good reading of 60 Ohms. 



Figure 3 b: Diagnostic Socket

It is possible to measure the vehicle with a meter and a scope, but the preferable option for speed and accuracy, is to use a scan tool to perform a global scan of the vehicle. Aftermarket diagnostic tools have been facing a growing challenge of how to communicate with, and interpret codes and data from all of the modules on the entire vehicle network. Poor network coverage means that you may miss (not be able to see) vital diagnostic data. Another area where the aftermarket tool is lagging significantly is its ability to display the current status of the vehicle network in a topology style. The vast majority of dealer tools perform a global scan upon initial communication with the vehicle. This technique ensures that a total vehicle state is used as a basis for subsequent diagnosis. In addition to this, the topological view can provide vital clues to the nature and location of any vehicle network issues. 

Figure 4: Network Topology

Figure 5: Fault cluster analysis

But I don’t have access to dealer tools in my workplace. Am I doomed? If you are limited to using aftermarket scan tools for your diagnosis, you’ll need help in the form of an analytical technique to support your diagnostic data’s critical analysis. Technical Topics have developed a Network Fault Cluster Analysis Technique to help with just that. 

The best advice is for technicians is to build their awareness of the new range of vehicle networking technologies. Attend some training, read some articles and get some hands-on research time with a modern vehicle. Build a baseline of information so that when faced with a problem, you stand a chance of differentiating between the good, the bad and the ugly. Spending some time researching Flexray, Ethernet and DOIP and V2X will pay dividends in the long run. If face-to-face learning is your preferred method, it just so happens that I know a firm which runs a very cool in-vehicle networking training course. 

James is running the following courses at Technical Topics HQ in Bridgwater: 

June 10th to 14th – EV Bootcamp 

June 18th and 19th – EV Level 3 

June 20th and 21st – VW Dealer Tool Training 

June 24th and 25th – Oscilloscope Masterclass 

June 27th and 28th – Peugeot & Citroen Dealer Tool Training 

July 1st & 2nd – IMI Diagnostic Technician Programme 

July 3rd & 4th – IMI Master Technician Programme 

July 8th to 12th – Diagnostic Bootcamp 

July 15th to 19th – EV Bootcamp 

July 22nd & 23rd – BMW Dealer Diagnostic Tool Training 

July 25th and 26th – Volvo Dealer Diagnostic Tool Training 

For detailed course information, please visit: 

Test your knowledge and analytical skills!

Online tests at assess diagnostic process

Autotechnician magazine has again teamed up with contributor and Big Day Out trainer Andy Crook to deliver free, online tests for independent workshops & technicians throughout 2019 to assess technical knowledge, process and diagnostic capabilities. The Autotech assessments have been created to help entrants identify any weak areas and address them in a confidential and fun format.

Andy, of GotBoost, has devised Autotech Test #7: LIN Bus. The online assessment consists of 15 questions designed not just to test your knowledge of LIN Bus systems, but your understanding of the information presented and your ability to analyse the data and waveforms provided in order to draw diagnostic conclusions. Andy explains:
“It will also challenge your depth of networking knowledge; including technical vocabulary, system design and operation.
“The scenario is based on a Ford S-MAX charging fault, a job that we have fixed here at GotBoost, so represents the real-world challenges technicians face when dealing with intelligent charging systems.”

What score will you get?
Once registered, users have access to multiple choice tests, covering vehicle systems, theory and diagnostic scenarios. Once completed, score sheets marked with the correct answers are instantly emailed back to the participant, along with supporting learning material.
Register or log in to take the case study at


Autotech 2019 is sponsored by:

High Amperage Ampera

High Amperage Ampera – Part Two – By James Dillon of Technical Topics.

The recent SMMT figures for new vehicle sales provide a bellwether for independent vehicle workshops. How so? Well, if we review the 2018 sales, they are indicating a significant shift, one that many of my independent aftermarket colleagues may not be completely conscious of. 

From January 2018 through to December 2018, the mix of vehicles sold was: 62.3% Petrol, 31.7% Diesel and 6% Alternative Fuelled Vehicles. Comparing the number of Diesel and Petrol over recent history (2017 and 2016) shows the change even more distinctly. Diesel market share by volume dropped significantly. The figures are 2016 – 47.7%, 2017 – 42%, 2018 – 31.7%. The reason for this is that buyer demand has dropped significantly. 

Many vehicle manufacturers have pulled diesel vehicles from their product range, such as the Vauxhall Corsa, Toyota Avensis, Seat Toledo, Skoda Fabia, Fiat 500X, Kia Rio and Mitsubishi Outlander. Some vehicle manufacturers no longer offer any diesel variants, including Volvo (post V60), Porsche, Suzuki and Subaru. So, what are the implications for the diesel vehicle population and for independent workshops? Well, simply put, less diesels to service and repair. The latest government figures for all vehicles (licensed cars at the end of the last year) shows a 58.8% petrol to 39.9% diesel split. 

Another influencing factor on the squeeze on diesel may be the MOT regulations, with regards to tightening the emissions standard (and the focus upon tampered emission control devices such as DPF and EGR). The implication being that reversing emission system tampering is very costly; the unreasonable economic equation of a proper repair was probably what led to the tampering in the first instance. Tighter MOTs alone could see the existing ‘stock’ of used diesel vehicles shrinking. The twin factors of fewer new sales and increased ‘scrappage’ mean that the decline is likely to be quite rapid. The cynical and conspiracy theorists among us could suggest that the MOT measures are, in fact, a scrappage ‘scheme’ by proxy – considering that the ‘natural’ rate of decline is before the government bring out the big guns of change (fuel duty and road tax increases) to really encourage a shift away from diesel. 

So, where does this leave us? An increase in petrol engine vehicles for sure. The continued increase in Hybrid and Electric Vehicles – highly likely. The SMMT data above shows the continued surge in Alternatively Fuelled Vehicles (20.9% of total sales 2018), even though this is from a very small base. How should this influence the skills mix in our workshops? You’re probably going to need to upskill on the finer points of petrol engine management diagnostics, fuel trims, ignition analysis, fuel injector analysis and the like. Given that the predicted growth will be in Hybrid Petrols (with pure EV likely to remain a developing segment), certified high voltage training, motor/ generator and battery management systems diagnosis will complete your skills mix nicely. It’s critical to consider that your high voltage training should go beyond the basics of make safe/remove and repair and must include practical aspects of HV system diagnosis. Which leads us on to the high amperage Ampera, (see Part One of the case study in the May 18 issue on HERE). 

Figure 1: Dash Panel Warning

Our Vauxhall Ampera would not drive. It would power up on the ignition switch, but it was unable to move under its own power. This could be considered as the equivalent of a crank – no start condition of an internal combustion engine vehicle, see Figure 1.



Figure 3a: Hybrid Motor Current Analysis

An additional issue was that the vehicle would not charge from its mains charging lead as the battery was in a low state of charge due to the fault. The problem occurred whilst the owner was driving the vehicle. The warning came on the dash and the vehicle soon lost power and it had to be recovered back to their house. Unfortunately, they had real trouble finding a repairer locally to investigate the source of the problem, including the franchised dealer. A scan showed a High Voltage fault, see Figure 3a and current analysis indicated that the motor generator unit was pulling a large amount of current during the self-test phase on a single motor winding. The system self-test applied significant current to the winding to check for insulation faults. Our odd phase showed 350 amps being drawn prior to the fault being set and the vehicle dropped into no-go mode. 

We used a variety of other test techniques on this motor generator as an experiment to see which methods were most effective to diagnose this type of issue, including a device the Japanese manufacturer’s rate for this test, the milliohm meter. The milliohm meter is a highly sensitive device that it is highly influenced by temperature. The manufacturer states that the vehicle should be at rest for a period of 8 hours or longer to normalise the readings. The milliohm meter is sensitive enough to detect the difference in two slightly different lengths of standard wire, down to 1/100000th of an Ohm or 0.00001 Ohms. 

When this unit was applied to the motor windings, two of the phases showed 36.6 milliohm and the third showed 40.0 milliohm. The motor shares two sets of windings across each pair of phase connectors. Therefore, two sets of windings are reading differently – one too low due to the shorted winding and one set reading ‘correctly’. The term ‘correctly’ is a ‘ield based assessment, as Vauxhall do not give a specification. 

Photographic evidence of the root cause was taken after the transmission unit was stripped and disassembled. The windings clearly show signs of overheating, causing the short circuit and the increase in motor current. 

The question remains as to why the smaller motor generator did this? For now, we have to perform calibration relearns on the replacement motor and check that the function of the motor driver hasn’t been harmed by the excessive current caused by the original fault. 

Figure 1: Dash Panel Warning

Figure 2: Scan Tool Diagnostics 

Figure 2a: Diagnostic Trouble Codes

Figure 3: Insulation Tester

Figure 3a: Hybrid Motor Current Analysis

Figure 4: Milliohm Bad

Figure 4a: Milliohm Good

Figure 4b: Milliohm Connected

Figure 5: The Motor Generator

The ‘4-Rights of Data Gathering’ – By James Dillon of Technical Topics

Many technicians who succeed at fixing more cars faster generally adopt different fault finding techniques. Those who are doing mostly service and mechanical repair don’t need or don’t want to go much beyond basic fault codes and rudimentary testing. If it’s not a simple fault, these folks are happy to refer the customer elsewhere, or to ‘get a guy in’ to do the ‘difficult diagnostic stuff’. I understand that. These people are happy earning money from service and repair, so they don’t have to get involved in this type of work. 

An interesting question to consider is what factors would classify a fault as too difficult? What makes it a fault that can’t be done by the service guy? Would it be a symptom and no fault codes? Or perhaps many fault codes and no symptom? Or even a fault code that fitting the fault coded parts wasn’t fixed by replacing those parts? How about your bog-standard misfire diagnosis? Does this fault classify as too difficult? Not at the outset maybe, but what if new injectors (or a new spark plug and coil pack for petrol engines) didn’t solve the issue? What if compression was good on the gauge, so it had to be something electronic? Well folks, hang on to your metaphorical hats, because I’m going to take you down a potential rabbit hole of a diagnostic problem which revolves around a simple engine misfire. 

The guiding principles of misfire diagnostics, when I was a young whipper snapper, was to validate basic elements required for combustion, such as compression, ignition (compression or spark), fuel and timing (all these things in the right order). Several tests exist to ‘prove’ each of these things. It’s likely that the equipment present in the workshop, and the relative skill level of the tech applying them, will define
the outcome of the data gathering. Of course, almost every technician can use a compression test gauge (petrol or diesel), but perhaps it takes a special sort to consider the frailties of this test without external guidance or influences. 

My very old and worn out saying ‘the 4-rights of data gathering’ – that you must measure the right thing, in the right way, at the right time, with the right tool – comes to bear. When you can’t diagnose the problem, one of the 4-rights ‘rules’ will have been broken. The compression test has a major flaw; there is a compression fault that will pass the compression test but will cause a misfire condition. ‘The 4-rights of data gathering’ were developed to enable technicians to be critical of the results they gathered and to challenge test results which seemed ‘OK’. Over the years, many of the jobs that appeared at Technical Topics HQ had the accompanying technician statements of what couldn’t be wrong, because these ‘things’ had been tested already. Yes, but was the right thing measured, in the right way, at the right time, with the right tool? Invariably, not. There would be something, often very ‘minor,’ that had slipped through the first garage’s diagnostic process. 

So, onto our problem. We are faced by a vehicle with a misfire. My favoured technique is to validate cranking effort via the starter motor current draw. This method requires no parts to be removed, so it’s quick and accurate. We simply hook a current clamp to the battery negative cable, measure the battery voltage directly and crank the engine for 10 seconds. The principle is that the mechanical effort of the engine will cause the starter to pull peak current during each TDC event, in the same way your arm must apply more pressure on the socket and bar when you wind the engine over by the front pulley bolt after a timing belt change. We simply look at the current peaks and check for the differences, in exactly the same way that we would look at the needle on the gauge of a traditional compression tester. The current clamp test technique earns you more money than the traditional test, as it saves a whole heap of time and is highly unlikely to cause mechanical breakages to spark plugs or glow plugs. 

FIGURE 1: Relative compression test, current clamp on battery cable

Figure 1 shows the resultant current waveform from the misfiring engine during cranking. It can be seen that there is an imbalance in the mechanical effort, as the current draw is different on corresponding peaks, there is one peak for each of the cylinders. Now, let’s see if the gathered data passes the 4-rights sense check. What are your initial thoughts on the cause for the imbalance? Please take a second to consider the answer before you read on. 

Thought one, which may be derived by the Anchor Thinking principle, which we covered on the recent Big Day Out in Reading, is that the lower current draw cylinders (they would also be shown as lower on a compression gauge) are indicative of our problem. 

Thought two, is that the higher compression is our problem cylinder. This thought is counter intuitive, as we are conditioned to consider low is bad – after all, who ever saw a compression that was too high, let alone one that was too high that caused a compression issue? 

The judgement you make based on this data is going to guide your next step and your next test. The benefit of adopting novel data gathering techniques is that non-intrusive testing is possible; mechanical strip and fit then occurs as part of the rectification, not as part of the diagnosis. In practical terms, the vehicle can be fully diagnosed whilst remaining in a running condition. This is particularly useful where mobility and workload planning are influencing factors of workshop management. 

Back to our thoughts on diagnostic direction, both answers may be correct and this is often the dilemma we face during diagnostics; a definitive diagnosis cannot be drawn based on this limited amount of data. To be definitive, we should challenge this data/result with another test, or at least have comparative or baseline data. Remember that data must have context to become useful information. 

Our compression problem is not unique in the fact that our comparison in data is uni-conditional (99.9% of the time is evaluated against a ‘too low’ value). We will progress to the next step in a subsequent case study. 

James’ highly recommended Diagnostic Bootcamp training courses will help you fix more cars, faster. See his website for details: 

Big Day Out Reading: Group diagnostics on the ‘Kick Ass’ KA

It’s not really in us to say you missed out if you didn’t come to our ‘Big Day Out’ on Saturday 30 June, but well, you did! This years’ event was held at Reading College and the entertaining and highly knowledgeable Andy Crook of GotBoost and James Dillon of Technical Topics were the hosts.

In a change from the previous format, which included three in-depth training seminars, we wanted to make this event more interactive and, right from the off, the leading double act of Andy and James had the attendees literally on their feet and involved. Using a Ford KA with pre-installed issues, the purpose of the day was to work through these faults as a group, while challenging thought processes, discussing the psychology of diagnostics and formulating workable hypotheses, which were then tested and confirmed or disproved.

That’s not to say that everyone had the same opinion on where to start, or what to do next, but that was the point – everyone had a good time doing it.

Every element of the day was focused on taking this real-world example and helping technicians improve on customer interaction, diagnostic process, evidence gathering and recording, testing procedures, maximising time and money, and getting that all important first-time fix.

Ross Kemp of Scantec Automotive brought along his technician son Lewis as well as his partner and company secretary Elisa- Jane. Ross had this to say about the day: “Ive really enjoyed it. Its quite nice to merge the psychology with the diagnostics.

It’s quite interesting to see how some people answer the questions they’re asking like ‘what would you test next?’ There’s the theory or the real-world answer – with a particular vehicle I’d disconnect that sensor, it might only tell me half the answer, but it’s a thirty second job. So, it’s been very interesting as I’ve never seen anyone do this looking at the psychology behind diagnostics. They (Andy and James) make a good team”. Partner Elisa adds: They’re really engaging together. They have different styles of teaching and bounce off each other extremely well.” Getting delegates to suggest the next move and moving around the workshop to show which camp they fell into, went down well and kept everyone engaged.

The training session involved more than just the technical aspects of diagnosing and fixing the car. Managing customer expectations and charging for diagnostics were also discussed, to arm technicians and workshop owners with all the tools needed to promote a first-time fix and happy outcome for the workshop and customer. From quizzing the customer to the final bill and everything in between. James talked about how he produces a storyboard for the customer invoice. This storyboard can then be used to justify expensive diagnostic work and is also an audit trail for the technician, so you can go back through the notes and see where you perhaps went wrong and it sent you in the wrong direction. Although at times this thorough and detailed process may seem laborious, it saves you time in the long run. James explains: “Slow the fault-finding process down by preparing the customer at the start otherwise you put time pressure on yourself and being faster, actually makes you slower. By using a planned and methodical approach you’ll get to the answer.”

A few words of wisdom from the trainers:

“Measure the right thing at the right time, with the right tool and in the right way”

“Unconsciously incompetent – basically, you’re shit and you don’t know it”

“Our cognitive bias is to see the easiest solution as the most probable problem.”

“You have to understand what you expect from what you are testing and understand the context – what has your result proved without making any assumptions?”

What delegates thought of Reading’s Big Day Out:

“Just wanted to say thank you to you and the team for yesterday. We all had a great time and can’t wait to come again next year.”DA

“A great event from a great magazine. Really inspiring discussion and not one of your usual PowerPoint courses. It’s always nice to hear James Dillon talk and this was no different, truly passionate and thought provoking. A very enjoyable day out, and a bargain compared to the entry fee! Thanks guys!” MA

“Fun, engaging and interesting business/technical content delivered by Andy Crook & James Dillon today – was certainly worth the 4am start!” EJ

“Great day out guys as always. Great presentation, great food and some great people, keep up the good work.” RK

If you missed us this time don’t worry – there’s another Big Day Out event booked for Saturday 27th October at EMTEC in Nottingham. Email or call 01634 816 165 to book your ticket! Don’t delay, they go quick!

Keep an eye on Facebook and Twitter for the latest news and tech advice.


High Amperage Ampera – By James Dillon of Technical Topics

The market is moving towards a point that borders ‘beyond doubt’ regarding the medium-term electrification of light vehicle transport. The impact of this for repair garages and workshops is that they will absolutely have to get hands-on with the service, diagnosis and repair of electric vehicles. Uniquely, alongside the business opportunities that electric vehicles present, there are significant safety risks, which shouldn’t be underestimated. These risks can be mitigated with appropriate education and training, using the correct equipment and implementing the correct procedures and processes.

The diagnostic case reported here has been carried out following the correct processes and procedures by a hybrid and EV trained technician. This article will indicate the types of processes, techniques and procedures that may be necessary. In all cases, the vehicle manufacturers’ procedures should be followed by a suitably qualified EV technician.

Here at the Technical Topics workshop, I have been involved in the diagnosis and repair of hybrid and electric vehicles for the past 10 years. Being an early adopter, I’ve had the chance to get hands on with some interesting diagnostic cases. Once such case, which is currently ongoing, is that of a Vauxhall Ampera, a type of extended range electric vehicle.

Initially, the Ampera uses energy from a 16.5 kWh battery pack to drive an 110kW electric propulsion motor. The batteries are charged from the main’s electrical infrastructure as well as from a 55kW on-board motor/generator. This motor/generator is driven by the kinetic energy of the vehicle during regenerative braking (KERS). The Ampera also has a 60 kW 1.4 l internal combustion engine, which is used primarily as a supplementary drive source for the motor/generator. This energy is delivered directly to the propulsion motor with any excess being stored in the battery pack. The three drive sources (main motor, generator motor and internal combustion engine) can blend two of the three sources depending on the operating mode.

Screen Shot 2018-05-24 at 19.52.37We recently had a poorly Ampera in the workshop that would not drive. It would power up on the ignition switch, but it was unable to move under its own power. This could be considered as the equivalent of a crank – no start condition of an internal combustion engine vehicle, (see left) Dash Panel warning. An additional issue was that the vehicle would not charge from its mains charging lead. The battery was in a low state of charge due to the fault. I hoped this would recover, but it was an unknown factor and this was communicated to the customer.

The problem occurred whilst the owner was driving the vehicle. The warning came on the dash and the vehicle soon lost power and it had to be recovered back to their house. Unfortunately, they had real trouble finding a repairer locally to investigate the source of the problem, including the franchised dealer. There appears to be real business opportunity here for early adopter garages to position themselves as local market leaders in the diagnosis and repair of this type of vehicle.

The suggested diagnostic process for hybrid and EV is to assess diagnostic trouble codes early on in the process to assess the type of failure and to see that the failure mode doesn’t represent a safety issue for the technician. A scan of the problem-child showed a DTC for drive motor high current (see below, DTC capture). At this point, the technician should be able to develop a test and measurement plan, and ascertain whether or not the vehicle should be made safe prior to testing.

Screen Shot 2018-05-24 at 19.52.55Screen Shot 2018-05-24 at 19.53.08

In this case, we assessed the GM technical info for the specific DTC. The guidance was to make the system safe and then commence testing. The test specified guided the technician (me) towards a system-off insulation/isolation test. The DTC information stated that the motor generator current exceeded the fail threshold during system initialisation; consequentially, as a safety feature, the vehicle enters a form of motive suspended animation. The external charging port is also isolated after the self-test failure is tripped. This has implications for the main battery state of charge.

Screen Shot 2018-05-24 at 19.53.53The isolation test is performed using a high voltage insulation tester (see right) under the correct conditions, whilst wearing the correct safety gear. I ran the test, which the system passed. The vehicle manufacturer’s trouble code diagnostic tree suggested as a next step to replace the inverter and if this didn’t cure the issue, to replace the motor generator. Wow! Better get a big parts canon, as this method required the firing of some very hefty and pricey ‘try-some’ parts. I chose to resort to some alternative testing methods to better establish a root cause.

Screen Shot 2018-05-24 at 19.54.12Using the PicoScope and a 3-phase induction current clamp set, I attempted to test the system’s function (see left). The clamps were placed in line between the inverter and the motor generator, half way along the potential problem.

The system was re-initialised and the appropriate safety gear was donned. The system was turned off and back on and the code reset whilst the current was monitored.

Screen Shot 2018-05-24 at 19.55.06The waveform (see right) shows that one of the motor phases was pulling a peak current of 350 amps during start-up. This looks like what was tripping the system and setting the code. This form of testing enabled me to observe the symptom directly. However, the next challenge is to try to diagnose the root cause: Is it the motor, the cables, the inverter or something else? I’m awaiting customer authorisation to proceed with the next level of testing and if I get the go-ahead, I’ll detail the next steps in a subsequent issue.

If you’d like to build your knowledge and experience, and gain a nationally recognised Hybrid and EV qualification, get in touch with Technical Topics. They are running a Hybrid and EV Diagnostic Bootcamp, which will equip technicians with the skills and knowledge to make money from diagnosing the next big thing in automotive transportation.

You can also catch James Dillon at Reading College on Saturday 30th June, see page 8 for details, call 01634 816 165 to book a place.

A question of choice – By James Dillon of Technical Topics

Screen Shot 2018-03-17 at 09.16.41An often debated question in the circle of my fellow motor vehicle technicians, either online in trade forums or at trade shows and seminar events, is ‘which scan tool is best?’ It is an open question that, generally, gets the response of ‘it depends’. The reason for this is because there are just so many variables. To narrow the scope of the response, the questioner will usually get the following types of question in response: which cars do you cover? What sort of jobs are you seeing? What sort of functions is your existing scan tool failing to provide?

In an attempt to define a suitable answer (I was going to say ‘the right’ answer, but decided that ‘right’ is too subjective) I have contemplated the scan tool scene and tried to consider the scan tool against the backdrop of motor vehicle technology, and to categorise the physical choices into well-defined bands of type of tool. Figure 1 shows the first consideration, which is the backdrop of scan tools (factory OE versus aftermarket) against vehicle technology. Vehicle technology, and specifically the electronic controls that make the new tech function, is exactly the thing the scan tool is expected to interact with and perform functions upon.

In my experience, we are experiencing a scan tool capability gap; vehicle technology is outpacing aftermarket scan tool development. This may not be news, as the aftermarket scan tool was always a bit behind the factory tool. However, the sheer number of systems on the vehicle has expanded rapidly and the aftermarket scan tool engineering teams have not expanded their reverse engineering development work at the same rate. This means that vehicles, vehicle systems and vehicle system functions are missing, when compared to the factory tools. This gap may only be bridged by the aftermarket tools companies expanding their engineering teams, which will inevitably lead to higher software, purchase and subscription costs.

Screen Shot 2018-03-17 at 09.17.11FIERCE COMPETITION 

Herein lies problem number one. The aftermarket scan tool manufacturers currently make less money from scan tools than they used to. The competition in the market is fierce and the Chinese are beginning to dominate the features/ functions/cost benchmarks for aftermarket scan tools.

This has driven the end user price down. A consequence of this is that there may not be enough cash in the pot for European scan tool manufacturers to compete with Chinese companies. In fact, in order to address this, many of the European scan tool manufacturers already outsource engineering R&D ‘offshore’ to China in order to try to stay competitive (with the Chinese!)

Problem number two in the economics of the scan tool market is the relative price reduction that many of the vehicle manufacturers have applied to the factory scan tool over recent years. A factory scan tool for some of the German vehicle manufacturers costs well under £1,000, compared to the bad old days when these tools cost well over £10,000. This puts additional pressure on the maximum price an aftermarket scan tool provider can charge. The vehicle manufacturers seem to have adopted the mobile phone PAYG model: Buy the handset relatively cheaply (but tied to their ‘network’) and buy diagnostic minutes.

We could conclude that the aftermarket scan tool businesses will never be able to afford the resources to develop a product that will rival the vehicle manufacturer equipment, hence the capability gap will continue to expand over time, leaving the dissatisfied vehicle technician with a choice; buy a general tool (or tools) with gaps in coverage and miss out on paying jobs or buy the, or several, vehicle manufacturer tools and operate at ‘dealer’ level.

Buying the dealer tool may seem like the obvious choice, but it’s not without issue. Consider the average garage will service and look after 10 or more car brands – this means that the same number of dealer tools must be bought, which will be much more expensive than the single multi-make aftermarket scan tool. As each vehicle manufacturer tool works very differently to the next and each requires different PC specs, there is huge complexity in infrastructure, training and operation.

The choice facing the general garage ends up looking like choosing something from the scan tool grouping shown in Figure 2. This illustration shows there are six distinct ‘choice’ areas. Moving from basic functions in level 5 at the bottom, to high function ‘creative problem solvers’ at the top or, indeed, a combination of tools from several groups

Many of the more go-ahead, diagnostically biased businesses (the top 10%) seem to have a mix of tools from the top two tiers. Typically, they will have tool solutions to fit specific problems. Using the dealer scan tools brings big benefits; they can do what the dealer can do, almost always.

Dealer tools benefit from the synergy of what I call ‘joined- up’ diagnostics; the complete integration of vehicle technical data (wiring, R&R, TSBs, Guided Fault Finding) and the faulty vehicle, which is the best way to quick and accurate diagnostics. Using the dealer scan tool is a steep learning curve and will require training and support, but the benefits are immense when compared to an aftermarket tool.

Another significant benefit of using the dealer scan tool is the ability to go ‘online’ to the OEM server. This may be required to run guided diagnostics, to program and code components and to perform software updates, which may solve the vehicle’s reported problem. The online aspect is typically not possible with an aftermarket scan tool. The online element of vehicle diagnostics is also making it much more difficult for the aftermarket scan tool engineers to ‘reverse engineer’ and expand the features and functions of their own tools. Vehicle manufacturers are data mining the online sessions for various reasons, including prognostics. If they notice a ‘user’ polling vehicle functions repeatedly, or observe strange patterns of behaviours (running every actuator test one after the other), they are likely to realise what’s going on and ‘terminate’ the session and possibly the user account.

Big brother watching is limiting the scope of reverse engineering which, in turn, is causing the capability gap to widen. So, the answer ‘it depends’ seems to favour the diagnostic solution of an aftermarket scan tool and several dealer tools. But this really does depend on something that is beyond the scope of the average workshop. It falls squarely in the lap of our trade bodies and interest groups – so get campaigning!

“Brexit will undoubtedly have some impact upon the availability and support of the vehicle manufacturers’ diagnostic tools to the independent workshop as, after all, it is European legislation that made this an option in the first place. If Brexit goes badly, the impact on the independent workshops will be hard felt. The prospect of dead dealer tools, no server access and highly complex broken-down vehicles paints a disastrous scenario.”


James Dillon’s Diagnostic Bootcamp is a five-day, fully immersive, intensive training experience and the next one is taking place in the Technical Topics workshop in Bridgwater on Monday 9th April to Friday 13th.

The course covers the core skill areas of Electrical Fault Finding, Oscilloscope Diagnostics, Engine Management Petrol and Diesel as well as CAN Bus & In-Vehicle Networking.

James Etherington, owner of VDS Performance, says they are “Excellent training courses, delivered in an easy to understand and enjoyable style by one of the best diagnosticians in the industry. Small groups and practical sessions make it a must for anyone looking to learn and develop their knowledge and diagnostic skills.”

Over the five days, James covers the most important aspects of vehicle diagnostics within his training workshop, equipped with up-to-date equipment and a wide range of modern vehicles to practice on and learn from.


Electrical – Using and interpreting vehicle wiring diagrams, Converting complex diagrams into simple test plans, Earth back testing, Different circuit types and structure, Practical Volt drop testing and CAN-Bus impact on traditional circuits and troubleshooting.

Oscilloscope – Triggers & Advanced Triggers, Masks and Alarms, Bandwidth and sample rates, active wheel speed sensors, In-cylinder Pressure Analysis and Waveform interpretation and analytic software.

Petrol Injection – Oscilloscope diagnosis of key components, Emission control devices, Fuel pressure including test and measurement, Common faults and fixes.

Common Rail Diesel – Low and high-pressure fuel supply system, Fuel quality analysis, Inlet metering and fuel pressure control, high pressure pump and pressure generation, Diesel injectors, testing and analysis (Piezo and solenoid), Diesel Particulate Filters, additives and key sensors.

CAN Bus & In-Vehicle Networking – Recognising types of vehicle networks, Understanding network layout and test techniques, Using and interpreting vehicle wiring diagrams & tech data for speedy and efficient diagnosis & repair, Using OEM, PassThru and aftermarket scan tools for in-vehicle networking system diagnosis, plus coding and programming and what to do when it goes wrong.

PHONE: 01278 428 699