scanning with ignition off

   #1  

Dubstuff

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This might be a stupid question but is it normal to be able to scan engine ecu fault codes with ignition off?
 
   #2  

PetrolDave

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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.
 
   #4  

JMR

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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.
 
   #5  

Dubstuff

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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
 
   #6  

JMR

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