How accurate is vagcom?

**tosher777** · 12-08-2010,10:14 PM

Hi again.

I was considering purchasing a vagcom interface with the relevant software to use with my laptop. Before spending the money I would like to know from other users how acurate they are at picking up actual faults in sensors. For example; if an airbag warning light comes on for no apparent reason and vagcom picks it up as a faulty impact sensor, could you go ahead and buy a new sensor in confidence knowing the problem was going to be sorted or would vagcom give the same faulty sensor reading even if the fault happened to be with a connector or corroded wiring in that same circuit, hence blowing a shed load of cash, replacing a perfectly good sensor and still have the same problem with a wrong diagnosis ?

Regards: Tosh

**onzarob** · 12-08-2010,10:21 PM

VCDS (vag-com) give you the same error code VW get on there machine..no more no less

Basically it reads the fault logged by the cars controllers.

**snapdragon** · 12-08-2010,10:24 PM

Tosher, you have started 4 threads on this subject, it's best to keep them all on one thread, rather than starting a new one for every reply.

**tosher777** · 12-08-2010,10:27 PM

Originally Posted by onzarob

VCDS (vag-com) give you the same error code VW get on there machine..no more no less

Basically it reads the fault logged by the cars controllers.

Is that a yes or a no?

**onzarob** · 12-08-2010,10:34 PM

Originally Posted by tosher777

Is that a yes or a no?

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

**tosher777** · 12-08-2010,10:38 PM

Originally Posted by snapdragon

Tosher, you have started 4 threads on this subject, it's best to keep them all on one thread, rather than starting a new one for every reply.

Ok bud. Thank you for pointing that out. Ive just realized how ive swamped the B5 section with my 'airbag babbling' Sorry guys.

I only started a new thread as an airbag fault in the title may have bypassed another member who is maybe thinking of purchasing a vagcom system and looking for a relevent thread. Seeing 'How accurate is vagcom?' in a title will hopefully lead them to the right place. Im always trying to think of others whilst seeking help and always try to give back as much as I get.

Kind Regards: Tosh

**tosher777** · 12-08-2010,10:45 PM

Originally Posted by onzarob

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** · 13-08-2010,07:05 AM

Originally Posted by tosher777

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** · 13-08-2010,08:14 AM

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

**martin1810** · 13-08-2010,10:55 AM

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.