Vag-com : Engine On Or Off?

[niallsan]

Hey all.

I have a rrrreeeeaaaallllllllyyyyyy basic question about vag-com.

 

 

Can you use vag-com with the engine running????

Ok, I assume you can because I know people use it to check engine timing, temperatures, etc....

 

I'm only asking because last year I tried to start the Galaxy and it turned, without starting, for maybe 3 seconds. It starts normally with the first turn-over of the engine, so I was nervous to try it again and abandoned the operation.

 

So what I need to know is the procedure. Do you start the car first, then connect vagcom. Or do you connect vag-com and then start the engine(which is the way I did it)?

 

Thanks

 

N

[alan_131]

I've done both, never had any detectable adverse side effects. Generally connect before starting the engine just so I can read fault codes etc in peace...

[SilverBeast]

I've done both too. You have to have the engine running to meaningfully monitor the sensor outputs, and also if you are logging these while you drive to track down faults.