How accurate is vagcom?

[tosher777]

Yes it is very accurate. But it doesn't test the system it reads the error logged by the cars computers.

Cheers Rob.

I think a pre-purchase inspection of the relevant connectors & wiring would put me more at ease and will hopefully prevent a mis-diagnosis

Regards: Tosh

[caldirun]

Cheers Rob.

I think a pre-purchase inspection of the relevant connectors & wiring would put me more at ease and will hopefully prevent a mis-diagnosis

Regards: Tosh

Have you checked for flood damage to the CCM and its connectors under the passenger footwell?

[passat 130 tdi]

simple answer is no - 1 fault code can have many definitions.

[martin1810]

Vag-com is the best most accurate scanner on the market for VAG vehicles. It is more or less 100% accurate with its fault codes as they are read straight from the ecu as Rob says.
What you think the code means is up to your experience. Neither vag-com or anyone else can tell you that. Most codes are divided into three possibilities.
Short to earth.
Short to +ve
Circuit broken.

Signal codes are further broken down.
Out of range
Positive deviation
Negative deviation
etc

So vag-com will happily tell you a door is open when it is shut, simply because the sensor or wiring are telling the ecu that the door is open. It's up to you to find the real reason.

[macquatic]

Perfect explanation Martin.
Any tool is only as good as the operator and his expertise using it.

[onzarob]

Any tool is only as good as the operator and his expertise using it.

hear hear, A very accurate tool and well worth every penny