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A question of choice – By James Dillon of Technical Topics

By autotech-nath on March 17, 2018

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



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