VW Passet faults - should I trust the VW Dealer???

Hi,

I wonder if someone could provide some advice - I've got a 2002 1.8 Passat which has got three warning lights which come on for a period o time and then go off again. They are:

- Traction control light

- ABS light

These two can either both be off for a time, then both on or one onl on.

- the third light now on is the emissions light - again the sam pattern - has been on for a couple of weeks and has now gone off.

Have taken it to my VW dealer and they have diagnosed a steering angl sensor (£300 to replace) and the Lambda probe (£100 to replace), but can't understand the on/off pattern.

When I've asked why the warning lamps seem to come on for a number o start-ups and then the fault seems to disappear they say that th warning lamp system is designed to operate like that. I would hav thought though that if there were sensor faults on the car they woul be on all the while; not go on and off in a cycle depending on th number of engine starts?

Could anyone confirm VW's comment or advise what this might mean? Many thanks for any help

-- teamtans

Reply to
teamtans
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If you buy or borrow vag-com you can check for yourself. check the connections first, it might just be the plug.

Reply to
Duncan Wood

Depending on manufacturer and the actual fault, fault codes can go through several stages, but I won't go into the full details.

When a fault has been recognised by the ECU, it will put on the appropriate warning lamp. Should the fault then clear (say a dodgy connection that becomes good when the connector moves slighlty), the ECU will recognise that the fault is no longer present. Now depending on how the ECU is programmed, it will either extinguish the warning lamp immediately (generally restricted to older stuff), extinguish the warning lamp on the next ignition off, keep the light on for x number of ignition cycles (typically between 4 and 8 depending on manufacturer), or keep it on permanently (generally only for EOBD emmision related stuff).

As for the faults, check connections first, especially on the Steering sensor, but I'd want to know more about the Lambda sensor fault. There are two lambda sensors, and depending on which one is showing as being faulty, could point towards other problem giving the impression of a faulty sensor.

Reply to
moray

Thanks both of you for replying. Appreciate it

-- teamtans

Reply to
teamtans

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