Audi Hints and Tips for Technician Manuals
Sunday, May 23rd, 2010ENGINE DOESN’T START
FAULT: Engine doesn’t start or stalls briefly after the start – ECU disabled
CAUSE: The ECU is intermittently disabled Because of a fault in the immobiliser
(transponder).Due to corrosion on the connectors of the immobiliser control unit there are often
loose connections.
SOLUTION: If the immobiliser control unit has no fault stored, the cause is a loose contact or an
excessive transition resistance on connectors or earth connection.
· Check the earth cable and earth contact for the immobiliser control unit.
· The cables of the control unit must be routed free of tension.
· With height adjustable steering wheels make sure the cable to the reading coil has enough
clearance. Observe the maximum adjustment range of the steering wheel.
· Attach the loose cable from the reading coil with a cable binder at a suitable point, as near to the
control unit as possible.
In case of persistent complaints replace both control unit and reading coil with tin-plated contacts
or with gold-plated contacts. A mixed installation of tin-plated and gold-plated contacts is causes
corrosion.· The old part number of the control unit is indicated using the V.A.G 1551
· For identification the new control unit has a brown mark or the plug end is brown.
