scanning with ignition off

[Dubstuff]

This might be a stupid question but is it normal to be able to scan engine ecu fault codes with ignition off?

 

[PetrolDave]

Some modules which have permanent power will scan with the ignition off, it's module dependent - if a module scans with the ignition off it's nothing to be concerned about.

 

[Dubstuff]

Some modules which have permanent power will scan with the ignition off, it's module dependent - if a module scans with the ignition off it's nothing to be concerned about.

Ok thanks

 

[JMR]

Some modules which have permanent power will scan with the ignition off, it's module dependent - if a module scans with the ignition off it's nothing to be concerned abo

i have tried to scan without ignition on ( sometimes I am in rush ) ( except those cars with electronic steering lock ) but no ecu ever responded.

 

[Dubstuff]

i have tried to scan without ignition on ( sometimes I am in rush ) ( except those cars with electronic steering lock ) but no ecu ever responded.

The reason I asked is iv got a a3 3.2 Quattro in with a strange electrical issue. Most of the time the car works fine, but sometimes the dash will not light up its (totally dead) and car wont start then 10-20min later its fine again. When I try to do a scan when its playing up the only thing VCDS can communicate with is the engine ECU. Anyway totally by accident i found i could scan the engine ECU with the ignition off but nothing else

 

[JMR]

a bit more info about your car ? Can we see a scan before and after ?