How intelligent is the VAG computer diagnostic

[Bolster 0]

Can anyone tell me if the VAG COM diagnostics just report on faults each time it is run or does it keep any history of faults?

[dr_mat 0]

It keeps a history since the ECU was last reset (i.e. the power was removed).

Don't know if it records the dates of faults, but it will list previous faults, certainly.

[Bolster 0]

And how many volts does it require to make an accurate diagnosis? ie Does the engine have to be running? 13+ volts?

[dr_mat 0]

AFAIK you can plug into the computer without the engine running, and read off the past history. But I've not used it, I've just read about it on the forum... Can't say for sure what you can and can't do with e.g. a screwed alternator..

[Jonathan 0]

If you give me an idea of what you are trying to do, I can probably tell you whether VAG-Com can do it or not.

 

Jonathan

'94 VR6

[Kevin Bacon 5]

The ECU doesn't time stamp the faults since it doesn't have an internal clock. As Dr_mat said, the codes are stored until manually cleared or disconnected from the battery for 15 minutes.

 

VAG-COM can be used with the engine off or when running but with the engine off, the real time measurements (throttle position, engine rpm, temperature, ignition timing, injector pulse speed, engine load etc) obviously can't be gathered.

 

I can take some screen shots for you if required, in fact, there is a thread somewhere on here already with screen shots and basic instructions.

 

Kev