Car has fault but dealer says nothing wrong - what next??

greyteam1959

Go back to the dealer and insist that they go for a drive with you until the car faults.However long that might be.
Sometimes these 'diagnostics' will not show up some very simple faults.
You could always go to another main dealer under the warranty....sometimes a different fitter might use his or her common sense and find the fault quickly.

AdrianHi

O2 (Oxygen) aka Lambda sensor is a possibility and seems to be hard to diagnose.
Have a read and see if you think it applies to your car:
http://www.lambdapower.co.uk/diagnosis/diagnostic_index.asp

Lorian

"cutting out when coming up to junctions" tells us a lot, rulling out a lot of the sensor issues as prime cause.

I'll lay a large virtual wager it's the idle air control valve as others have said. Personally I wouldn't bother cleaning it if under warranty, get them to replace it and also add an oil recovery filter to the main crankcase breather pipe. Worth checking none of the smaller breather pipes aren't gunked up at the same time.

What sort of car? some vauxhalls are really prone to the valve sticking, and others.

molerat

I had a similar problem years ago. The car would just cut out and not restart. They could not find a fault. The garage manager had the car for a week using it as his own and I had his (company) car. The fault did not occur while he had it. After I got it back it did it next day. Eventually they swapped a part from another car and all was ok. They then swapped the part back and the car did not start. Eventually sorted until the car had the problem 6 years later !!. Suprising how fast they changed the suspect part as I was paying (£300) for it this time !!

vikingaero

Try another dealer.

ukjoel

I have worked for several manufacturers and some dealers are good and some are awful. No way to tell really without knowing the dealers very well. If you let us know which manufacturer it is we may be able to advise on a retailer.

Previous advice about trying another dealer is spot on (if in doubt try 3 or 4) its within warranty so none of them will charge you.

I would ask them to put their master or senior tech on it as with most manufacturers only 50% of the techs need to be trained.

Whilst they tend to be qualified mechanics they may not all be familiar with your model or the technology used to diagnose problems.

Retailers also skimp on these pieces of gear as they can cost £12k each which means if three jobs all need it 1 will get it and the other 2 have an educated guess and charge the manufacturer for warranty work whether it fixes it or not.

I would also phone up the customer service line to complain and write a letter to the manufacturer and dealer Ideally from a solicitor quoting the vehicle as not fit for purpose and giving them another chance to fix it.

I would also ask the original dealer for a full list of the diagnostic tests they carried out for you, details of the equipment used and the results of each test (numerical results, not just a tick). Any letter to the dealer should be sent to the dealer priniciple, not the service manager.

Whilst this is last line stuff you sound like you have had enough so bring out the big guns. You may not have any solid grounds at this stage but the aim is to flag this as the right level so it gets taken very seriously.

I have seen several times the impact an email or letter sent directly to the top can have when it comes bouncing down. Its not pleasant if it hits your desk but otherwise always highly amusing.

Been in the industry 15 years and never seen a case go to court.
Retailer or manufacturer always backs down.

In fairness to the retailer intermittent faults are a pain to diagnose, but how many miles did they put on the car trying to replicate it?

Offer to leave them your car for a week and ask for a courtesy car.

Be persistent, do everything in writing, and deal with the most senior people you can get hold of.

ozvaldinho

I had a similar problem on a Seat Ibiza 1.4 petrol a few years back. The engine would cut out under decceleration when you change down a gear, meaning you'd have to bump start it at speed. Bloody dangerous and unnerving even for an experienced driver, but potentially lethal for a learner.
It was a problem with the throttle body and potentiometer, As with you, the dealer was useless. Luckily the internet is great for solving problems like this. I'd try HonestJohn.com and chances are you'll find someone with a similar problem.
What make of car is it?

Ivrytwr3

Sit a digital camera to record on the dash of the car. Once it faults show them the footage.

steveo3002

Ivrytwr3 wrote: »

Sit a digital camera to record on the dash of the car. Once it faults show them the footage.

picture of the dash wont help anyone

emweaver

I had this problem with my car and it was in the garage about 5 times before they could find the fault, eventually they said it was letting too much oxygen in. Anyway its now failed its MOT on CO2 emissions which another garage suspects is due to the lam sensor which they think also caused the cutting out