Volkswagen Diagnostic questions

[pepitopinoy]

Hi everyone

As i have put on one of my post, that after paying 80pounds for VW diagnostic because my airbag lights up on the dash. They have told me that theres a fault on the crash sensor. They have replaced it and they told me that there is now a fault on airbag control unit.

As i dont have a knowledge on this diagnostics, they told me that it comes out after fitting the crash sensor. But i am arguing with them that they should have told me on the diagnostic report. But they told me that during the diagnostic process, it only picks up 1 error and this come out after fitting the crash sensor.

I spoke to a local VW garage and they told me it should have come up on the first diagnostics if its faulty and not after fixing the first fault.

Is this true?

Any advice please?

[drewbar]

Id say second opinion is right, but they should have notified you that there was a chance that there may be further work needed after replacing the crash sensor.

[alexperkins]

Some faults, especially airbag ones, can pull up the same fault for two different things.

Though I do agree, normally it will come up as an exact fault code, so the technician might have just been being thick. Argue it to the death - thats what i'd do!! Or make them pay for the work you have just had done

[pepitopinoy]

Thanks for the reply alex/drewbar.I actualy already have a hot debate with them when i collect my car. And one of the service advisor has shown me a documents that shows the fault report..... I have a glimpsed on it and i have seen the report saying "SUSPECTED CRASH SENSOR FAULT"....i argue for a copy of the report and they refuse to give me as it is a confidential documents per say. They also told me that a bit of my panel was broken during the repair and they will replace it when the parts arrive.We'll im planning to storm the General manager tomorrow and hope to get good result.I have just ring my local VW mechanic and he is suspecting that the crash sensor might not be the problem, but the Airbag control unit.Thanks again. Any additional advice will be very much appreciated

[alexperkins]

Thanks for the reply alex/drewbar.I actualy already have a hot debate with them when i collect my car. And one of the service advisor has shown me a documents that shows the fault report..... I have a glimpsed on it and i have seen the report saying "SUSPECTED CRASH SENSOR FAULT"....i argue for a copy of the report and they refuse to give me as it is a confidential documents per say. They also told me that a bit of my panel was broken during the repair and they will replace it when the parts arrive.We'll im planning to storm the General manager tomorrow and hope to get good result.I have just ring my local VW mechanic and he is suspecting that the crash sensor might not be the problem, but the Airbag control unit.Thanks again. Any additional advice will be very much appreciated

Stay firm, and state that you will make a formal complain to Volkswagen UK if it is not resolved

[RUM4MO]

I have a glimpsed on it and i have seen the report saying "SUSPECTED CRASH SENSOR FAULT"....i argue for a copy of the report and they refuse to give me as it is a confidential documents per say.

Results of a diagnostic system scan confidential - that a lot of pants - this work was done for you and you paid for it, most if not all professional scan tools can save and transfer to a PC for record keeping and printing - what a lot of woffle - its just a pity that you can not just "jump ship" and get someone else that knows how to behave to do this work!!

[drewbar]

Confidential sounds like a load of bull mate, Its your car and they shouldnt be keeping any info from you about it. Ask to see any diagnostic print outs they have and all the paperwork relating to the job, if you fail to get anywhere with the aftersales manager, get in touch with customer services and the dealership will soon crumble too you lol with renault (where I work) this happens a lot and in many cases customer services often offer a contribution towards the work. Remember stay civilised mate but dont be a push over.

Im not guarenteeing (sp) this will work but its defo worth a try mate, often depends a lot age of the car and previous history with the dealership and stuff. Best of luck mate!

Another point that might be worth mentioning, they may have gone for the crash sensor over the airbag computer due to i'm sure the airbag comp will probally cost more and inflict more of a programming charge too.

[RUM4MO]

In reply to drewbar's posting, this (replacing the cheapest part first), still seems to be the way that some garages work. Now in the old days where systems could not talk back to the tech this might be sort of fair enough with the proviso that "you" had got "them" - the experts to do this work because they knew more than you and so they would sort or replace the right bits quicker than you, if you could replace lots of costly parts. Now with the newer generation of smart modules and good diagnostic tools, a trained and experienced tech is in a better position to get it right first time - or so we would believe as its the logic the dealers work by when advising you that they are best placed to fix things. I just can not get my head round why car dealers service depts do not seem t try to equip themselves with "golden modules or sensors" or "slave modules or sensors" - what I mean is robust referance parts that can be temporarily fitted to replace suspect parts (but can survive being fitted to a faulty system). This is common practise in the general test area in manufacturing and repair and overhaul industry where time and money would othwrwise be wasted. Doesn't the main dealer service sector really care if they need to carry out repeat repairs as well as wasting the private motorist's time taking the car back as little is any slow moving spares are now stocked on the dealer's shelf. Seems to me that the motoring public is paying the going rate for having the best repair facilites and spares availability at main dealers - and mainly just gets the service that they should expect from a back street garage - not good enough. A simple example of some of this was that I booked my Passat in for an MOT and to get the gearbox selector oil seal replaced, I ordered in, at that dealer, the oil seal, but they still charged me for investigating and diagnosing the source of the leak (I had told them that the vent was okay) and grumped about me supplying the seal, even although they admitted that it would have taken them one or two days to source a seal - they couldn't see how a few days without the car would be an issue!

The trouble is it is not the actual mechanics that are the problem, its the management team are too weak or thick to understand where or what needs fixing in the way they operate - as long as there is work coming in there must be no problems!

[pepitopinoy]

im planning to bring my car for a VW diagnostic test (different dealer)for a second opinion to see if there is really a fault on my airbag control unit.

Volkswagen told me they have cleared all the faults on my car so my airbag warning light is off and can turn on any minute. Does that mean if if they will diagnose it today(with the warning light still off) they cannot see the fault?

[alexperkins]

It its off, theres a good chance no fault will be flagged up unitl it is on

[RUM4MO]

One other thing, now that I've calmed down(!!), any diagnostic tool is only as good as the system it is connected into read faults. If there is any fault near the O/P or I/P area of the Air Bag Controller, that module will raise a Crash Sensor fault code - but it could be that the controller final output, or initial input stage for that function is faulty OR the wiring to that sensor is faulty OR the sensor is faulty. Its really back to what I said earlier, I'm surprised that the dealers don't have a "golden" or dummy sensor and wire to connect directly to the controller so that they can get it right first time. This would show up a hard fault in either the controller or the wiring or sensor. In your case it seems that you have not intermittant fault - so the dealer would not like YOU to be driving around with a dummy sensor fitted - or at least his insurer would not!

[pepitopinoy]

well, if i didnt complaint about the occurence of another fault, and i put my car to replace tha airbag control unit. They will surely do it costing me £355. But since i complaint, and demanded that they should fixed it at their cost, they are now telling me it might be faulty and they dont want to replace parts that are not faulty. They offer me a free diagnostics to see if the ACU is faulty, if its faulty i need to shoulder the parts and the labor is free. But i refuse and demanded that since they report it faulty it should be replaced at their expence. Now, i want to put my car for a diagnostic on a different dealer for a second opinion. But wondering if the fault can still be seen if VW told me that they have cleared all faults. If ACU is really faulty, and at the moment the airbag warning light is off because they cleared all faults, and they diagnose it let say tomorrow, can they still see the fault even if the warning light is off?

[RUM4MO]

I think unfortunately you are not in luck!! If the previous dealer cleared the stored codes fromm memory then that is that! You will now end up starting from scratch if you go to another dealer and that will always cost you more in the end. I'm not trying to sway what you do next but you must consider where you are now and what this problem has cost so far. One other thing, replacing this module will be expensive as you have discovered - do VAG offer an exchange system where your faulty one is taken in as an exchange? If this is not the case then maybe you need to remove this module and get it assessed by a module fixer and repaired, or exchanged by a warrantied one www.bba-reman.com springs to mine as one place that might provide a quick and cheap service. Hope that helps a bit - remember, if you are wearing your seat belt correctly and the seat is positioned correctly and you are lucky enough to avoid any serious incidents (how do you plan that?) then this car could survive in its present faulty and undesirable state which still being drivable - even with this module removed.

[drewbar]

well, if i didnt complaint about the occurence of another fault, and i put my car to replace tha airbag control unit. They will surely do it costing me £355. But since i complaint, and demanded that they should fixed it at their cost, they are now telling me it might be faulty and they dont want to replace parts that are not faulty. They offer me a free diagnostics to see if the ACU is faulty, if its faulty i need to shoulder the parts and the labor is free. But i refuse and demanded that since they report it faulty it should be replaced at their expence. Now, i want to put my car for a diagnostic on a different dealer for a second opinion. But wondering if the fault can still be seen if VW told me that they have cleared all faults. If ACU is really faulty, and at the moment the airbag warning light is off because they cleared all faults, and they diagnose it let say tomorrow, can they still see the fault even if the warning light is off?

If the light is out it doesnt nessasaryily mean there isnt a problem mate, there are 2 types of faults, stored faults which normally wont cause the light come on, these in most cases are not normally worth worrying about as they can often be voltage related i.e if you have a flat battery these faults can be stored on the computer but they wont affect the system in anyway.

However if there is a problem to the extent that the light has come on, this normally means there is a present fault on the airbag network, this is normally serious so you should get these sorted asap.

The problem your going to have with going into another dealer now is that they're basically going to want to start from scratch with a problem that may not even be there anymore, if they've cleared all the faults on the airbag computer, you should use the car for approximately a week and then get them to recheck it (free of charge of course lol) if anything has flagged up a fault code they should deal with that from there onwards, if nothing has flagged up, then there should be no further action nessasary really, if theres a serious flaw with the system it should illuminate the fault light on the dash to let you know.

With regards to exchange items, on an electronic computer, its pretty unlikely they'll be able to do any form of exchange on it as they're just not worth repairing as they're quite cheap to produce (despite the massive shelf price ) and yeah if you can afford it, go for a decent extended warrenty mate.

[RUM4MO]

One other thing I've just thought about, I believe that after a crash where the airbag has been deployed, it is considered that the airbag controller needs replaced. This failed crash sensor has not caused the controller to have been put into that "state" has it - wthout deploying the airbags? Maybe your dealer is not getting the true facts across to you very well. It may well just be some data has been stored in the controller memory and can't be read or cleared using the dealer diagnostic tool. Normally any fault likely to have prompted the "fail" indicator will remain in the individual module's memory until cleared by a scan tool and proir to that the "fail" indicator will remain on until maybe six engine restarts have passed after the fault has stopped existing. Your dealer has been checking the air bag controller so any stored faults will have been cleared and any new intermittant faults will have flagged up a warning on that system so that you know that there was a problem - although as I've said, they may have gone and got returned so the air bag warning light will have gone off again after six or so engine starts.