David Wagstaff looks at the essential tips that must be taken to promote a first-time-fix…
Cars are getting more complicated with every new generation and at the same time customers’ expectations are getting higher. They don’t really care about what goes on under the bonnet or behind the dashboard, when it goes wrong they just want it fixed. Taking it to a garage is an inconvenience, it could mean re-arranging work or struggling to do the school run. Taking it in once is bad enough, but if the repair is unsuccessful then customers tend to get unhappy quite quickly. They expect a ‘First-Time Fix’. Within the dealer networks this First-Time Fix is important; dealers are scored on their ability to deliver them. If the FTF rate drops too low, they could be penalised.
So how do we get that elusive First Time Fix?
Well, it starts with getting the right information. I recently looked at a Volvo V50 1.8 petrol with the EML on and exhibiting slightly poor performance. A quick plug in with a generic diagnostic tool gave a fault code of ‘P2006 Intake manifold runner stuck closed’. That could fit in with the symptoms, but not convinced it was telling me the truth, I connected to the genuine diagnostic machine to be given the code ‘ECM-0703 Brake pedal sensor signal too high’. Now, if you had believed the generic tool you would have gone down the route of a manifold fault. You could have spent hours looking for a non-existent fault. You could have even replaced some parts, cleared the codes and sent the car out, only for it to return. So, for starters, you need a tool that is going to give accurate fault reports.
What next?
Are you going to guess based on what it was last time or the part the dealers sell more of? Well, you have a fault code you can trust, so you change the part the computer tells you, right? Well no, we need to do a bit of investigation now. Can you verify the fault? By this, I mean, we are not just going to take the computer’s word for it, we are going to test and prove that the item is actually faulty. This is where live data and activations really come into their own.
Say you have a fault where the tailgate doesn’t open. Is it the switch, the body control unit, the latch or the wiring?
With a good diagnostic tool, we can look at live data in the body control unit as we press the tailgate release
button and watch the parameter change from unpressed to pressed. With this simple test, we can narrow down the area that needs investigating very quickly. If we get a pressed signal then we can say the switch is OK, the wiring’s good and the body control unit is seeing the command. Next, can we use activations to open the tailgate? Again, this will test power supply, the control unit’s ability to operate the circuit, the wiring and the latch. If one of these tests fails then we are closing in on the area of the fault. To narrow it down further, you’ll need to dig out a multimeter and a wiring diagram, but you should now at least know what bits you should be testing.
GETTING CONCRETE PROOF
This approach works well with sensor faults too. I recently had a car in with a fault code of ‘Particulate filter temp sensor voltage too high’. Yes, it is likely the sensor is faulty, but how do we prove it? The customer was catching the ferry the next day and driving with their family down to Italy. How could I be sure that if I ordered a sensor it would fix the fault? If I just changed the part the computer said and it didn’t fix it, I would probably have some very upset customers. Looking at live data, the sensor showed a plausible reading of 346oC, was it really faulty?
Looking further through the list of data showed another sensor in the catalytic converter, the live data for this showed 87oC. As this is further upstream in the exhaust it should be reading the same if not higher, so something is not looking right. Which one is wrong? To help pin it down I got an infra-red thermometer out and pointed it at the sensor in the particulate filter, it read 68oC. I could almost put my hand on the exhaust
without burning it, so definitely not 346oC. A final test with a multimeter showed the sensor to be open circuit. I had proved beyond doubt that the sensor was faulty. The next day the new sensor arrived, was fitted, codes cleared and the vehicle road tested. I was happy that the fault was fixed and could reassure the family that it would now be fine to travel.
This may all seem like a load of extra work, and when you are rushed for time, is it really necessary?
Well, doing this work puts you in control as you can clearly explain to the customer exactly why you have changed a part. The customer is happy you haven’t changed unnecessary parts and you haven’t got the headache of a car that bounces back. This builds customer confidence in you, they go away happier and
are more likely to recommend you to their friends. In the long term, your workplace is less stressful and you gain customers that are happy and spend more money with you.
That has got to be worth spending a few extra minutes on hasn’t it?
Becoming good at diagnostics is not something that can be gained by the purchase of a tool or an individual training course. It is a skill that needs to develop with experience.
It is detective work and as much about eliminating all the things it isn’t, as going straight to the problem. It
means gathering information from the customer and from tests, developing a theory as to what the root cause of the issue is, then carrying out further tests to prove or disprove this theory, finally coming to a conclusion and presenting this to the customer along with their repair options.
A good technician will then also reflect on their own work once they have found a result to see if they could
improve their own practice. Could I have got there quicker, or develop a test that would give more conclusive results? Do I fully understand how the system works or could I do with more training?
This refection can also be our downfall – I have often found myself saying, “Can I justify all this diagnostic time?” Or, “I should have tested this first?” The result is often not booking as much time to the customer as we should. A clear pricing structure, whereby a customer agrees to an initial assessment and a certain amount of time spent on the car, is better from both parties’ point of view. You don’t undersell yourself and the customer has a clear idea of what it is going to cost them. If you haven’t found a result in that time, you have to go back to the customer and ask if they want to spend more money looking for an answer. Keep the customer in the loop.
Above all, remember it’s the customer’s car, it’s their problem. Do not let them offload their problem onto you. If
they are struggling to get to work or get the kids to school, it’s not your fault, you didn’t break their car. Keep
communicating with the customer and try not to make promises you can’t keep about when it will be fixed or how much it will cost, just to keep them happy.
With a good diagnostic tool, we can look at live data in the body control unit as we press the tailgate release
