My son has a Seat Ibiza which is under warranty - He had an intermittent engine management light which Vag-Com said was Motor for input manifold flap. The dealer fixed this fault today under warranty (using our vag-com print out !) then gave this warning ;-

" You have to be careful using Vagcom as it can leave behind codes - If an electronic part then fails and they find this code embedded it it - they will refuse to honour the warranty ! " This isn't word perfect but gives the gist.

Does anyone know if they are legally entitled to do this ?

I suspect they are only trying to frighten us off from using vagcom because it may give us insights into shady practices and dishonesty by dealers :-

e.g. I once had a Vauxhall Omega which had an intermittent management light - the dealers would claim to find nothing substantial, clear the code and pack me off - this happened about three times - till the warranty ran out - then guess what ? Oh! yes they could find the problem now and

I can't see any real reason?

Sounds like a big pile of BS to me!

My understanding is that Vag-Com reads the workshop ID code from the controller, modifies the controller and then writes the same workshop code back again (unless you manually set the workshop code to something different). So your dealer is at best referring to an obsolete version of Vag-Com or else peddling bovine effluent.

By reading (and clearing) fault codes, you leave no traces. It is when you start to alter parameters, that you are threading on thin ice.

Some of the latest cars with highest tech ECUs (Ibizas don't qualify, sorry) actually do record stuff like how long it's been since fault codes were cleared, how long long / how far the car was driven with the Emissions Malfuction lamp on, etc.

However, the car cannot tell the difference between having stuff done to it with VAG-COM vs. having stuff done to it with the factory's tools.

This even if you clear fault codes on one of the latest high-tech ECUs or make "programming" changes to the car, the dealer cannot tell whether it was done with VAG-COM or with one of their own tools.

Lastly, there's a reason why all modern cars have the same diagnostic connector. It's because the laws both in the US/Canada and the EU specifically require that independent workshops be able to do diagnostics. The concept that a dealer or manufacturer would void a warranty because some tool other than their own has been used to do diagnostics on the on the car is rather at odds with this.

-Uwe-

You don't have to clear the code either just read it and report it to the dealer, that way you have made no changes and everything is as it was when the fault occured.

Some of the latest cars with highest tech ECUs (Ibizas don't qualify, sorry) actually do record stuff like how long it's been since fault codes were cleared, how long long / how far the car was driven with the Emissions Malfuction lamp on, etc.

However, the car cannot tell the difference between having stuff done to it with VAG-COM vs. having stuff done to it with the factory's tools.

This even if you clear fault codes on one of the latest high-tech ECUs or make "programming" changes to the car, the dealer cannot tell whether it was done with VAG-COM or with one of their own tools.

Lastly, there's a reason why all modern cars have the same diagnostic connector. It's because the laws both in the US/Canada and the EU specifically require that independent workshops be able to do diagnostics. The concept that a dealer or manufacturer would void a warranty because some tool other than their own has been used to do diagnostics on the on the car is rather at odds with this.

-Uwe-

Thanks Uwe

It was really quite funny - they said that "my printout from VAGCOM wasn't the actual fault, but we started to look there then found the fault"

What a laugh - He must have fed me the warranty crap to try and scare me off using it, or as my Dad suggests try and hide things. I just find it incredible that my print out was wrong, yet they found the fault close to that point.

The actual fault was a wire that connects to an acceleration column (???) to the boost point was broken. Apparently when the car was manufactured the boost point and the wires had been put in together and this had broken the cable.

Anyway, now it's fixed, the car is back to 50+mpg on Motorway runs, feels a lot quicker (I dont know why, just feels like it's got a lot more poke) and the annoying shuddering that i was getting when shutting off the ignition has completely disappeared.

So, all in all the problem was fixed, which I am pleased about

What a laugh - He must have fed me the warranty crap to try and scare me off using it

Some dealerships think they're high priests and seem to find it sacrilegious that the owner of the car might be able to get as much info from the car as they can...:-)

The actual fault was a wire

The ECU cannot tell the difference between an open circuit in a motor and an open circuit in the wire leading to that motor. So if you get a fault code that says: "Component XYZ: Open Circuit", you'd check both the component and the wires going to it with a meter.

-Uwe-