Training on the job

Maurice from Geebung Business Development Manager Posted   Latest   Edited  
Case Study
Driveability
P0205 - Cylinder 5 Injector "A" Circuit

Ford Territory 2008 Vin 6FPAAAJGAT8E91797

Some days I feel I am losing my diagnostic ability or maybe my sharpness to diagnose, but then I have a run of success and I realise I am not as bad as I think I am. 

Am I the only one to feel like this?

Well I felt pretty good today I had Karan my up and coming tech who is not long out of his time come into me this morning after diagnosing a Ford Territory misfire. Before he started I pre-empted by suggesting to Keran I bet this will be a coil.

Well some 30 minutes later Karen came in to tell me he tested the coil on cyl 5 the cylinder that was not firing and found it to be ok. I asked him what code was found and he told me the car had a P0205 (Inj 5) well I said why did you test the coil, and he said you told me you thought it would be a coil so I went straight for coil.

Well I deserved that one so I educated Keran, scan tool direction always takes precedents over anything we think. The fact that the DTC points to the injector means you do not need to check the ignition coil. I explained that he just wasted 30 minutes and cost the customer and extra half hour in labour chargers. I do this to teach him to think and to learn not to make him feel bad.

Anyhow I decided to come out and help give him some direction. I got him to hook up the pico to cylinder 5 injector. We had a flat 12v on both sides of the injector with the car running. I then suggested he try another injector just to verify we were hooked up correctly which of cause we were.

So I asked him why you think we have 12V and it is not pulling to ground and driving the injector. He said because we have a cam or crank sensor problem. I said then why is it working on the other 5 cylinder. Sure there could be a very slight chance we have a relactor wheel issue on one of the pickups, but this is not where we need to go just yet.

You need to verify your wiring to the PCM and after that yes we can check and verify the cam and crank signal and if all this proves ok then I would expect we have an injector driver issue.

Well I went back into my office while Keran unbolted the PCM and exposed the wiring terminals. He hooked up the scope to A8 terminal which was the injector 5 driver terminal and he had 0V. I came out and asked him what is this telling us? I reminded him how when he was an apprentice I taught him how to understand voltages and how to use voltages to diagnose open and short circuits.

It was obvious we had an open wire, and we had narrowed our issue down to the no 5 injector wire that ran between the injector and the PCM. No amount of wriggling would turn on our injector, so I showed Keran how to verify my theory was 100% correct.

I simply left my back probe in the terminal of the PCM and added a second back probe to the injector driver terminal of the injector and I simply joined a wire between each back probe and simply stared up the engine and bingo the car was running on all six cylinder once more.

The open wire was not easily found and due to time restraints it was more economical to run a new wire along the outside of the engine loom to the injector. With it all taped up it was hard to tell it was even there.

The customer was happy and Karan who is one year out of his time is learning something new every day. It is important to keep your staff learning and interested in their jobs, a happy staff means he or she is less likely to want to leave with in the near future.

+4

John from Beaver

 

Instructor
 

"Before he started I pre-empted by suggesting to Keran I bet this will be a coil. Well some 30 minutes later Karen came in to tell me he tested the coil on cyl 5 the cylinder that was not firing and found it to be ok. I asked him what code was found and he told me the car had a P0205 (Inj 5) well I said why did you test the coil, and he said you told me you thought it would be a coil so I went straight for coil."

I talk about this all of the time. When it comes to actually doing the diagnostics, forget everything you have been told or think you already know about the problem and test and prove what is going on right now. The suggestion that it "might be a coil" served to get Keran to start at a diagnostic point other than where a normal routine would have done. As well intentioned as it might be, and even if it is accurate, it can more often than not lead to trouble down the road. Just the idea that a shot from the hip denotes experience or knowledge erodes the need for a tech to have the discipline to always test correctly. That's the main problem with the way many techs use Identifix, and now we see that same error being built into scan tools and other service information outlets. TSB's and product knowledge has it's place, but they are not a substitute for a solid diagnostic routine.

"Well I deserved that one so I educated Keran, scan tool direction always takes precedents over anything we think." Totally agree here but I still have a concern about how often these misdirection's occur. In practice they often show up as two variations of the same theme. Two identical cars, same trouble code. The first one is "why did you do all of that testing, everyone knew that it was XXXXXX". The second one is the exact same symptoms only in this case the tech simply replaced the part as the first statement would direct and it didn't fix the car and so, "Why did you just change that part, didn't you test anything"? When someone moves the finish line like that it hurts the techs, not helps them.

+4

Maurice from Geebung

   

Business Development Manager
   

Thanks John, love your comments, I defiantly should not have suggested a coil without any diagnostic reason and I am certainly at fault and will not do this again, but at the time my intent was more to explain the type of miss being like that of a coil breaking down. It is so hard sometimes when talking with staff not to use examples such as the case here.

I never encourage any of my staff to take face value of a DTC, a fault code is only a direction to diagnose and validate the reason for the fault code. Sure a fault code the same as a previous car of the same model with the same symptoms could easily be tempting for a technician to take diagnostic short cuts but we all know how easy we can be wrong and we defiantly need to follow strong diagnostic protocol and always validate the cause.

Keran is only just starting to learn the diagnostic road and he has a long way to go but he has learnt a lot form this experience along with myself as I need to be very careful how I explain a symptom to my staff. I had Keran working on a BMW recently that had a whole lot of cam sensor codes and VTi codes and the problem was not what the codes indicated and this was a very interesting story. I will share it with you when I get time.

Cheers

+1

Steven from Spokane

 

Mechanic
 

Hello Maurice,

I think this was a learning experience for both of you guys, and everyone else. Don't play the guessing game, its bad for everyone.

0

Maurice from Geebung

 

Business Development Manager
 

Thanks Steve, no I never play the guessing game and my intention in thinking we could have had a coil problem was just form experience these 4.0L are notorious for coils breaking down it was never my intention for my staff to go straight for the coil without any diagnostic reason to do so. But yes it was a lesson for me too because there is a lot of power in our words and had I not have mentioned the coil, it is possible my tech would have not gone there first. As long as we learn form our mistakes and grow our experiences we will improve our skills. cheers

+1