checking oil AUDI A4 1995 B5 / 1.G APB Engine Ignition System Checking

28-5

Ignition coils, checking


Note:
Misfiring is recognized by the On Board
Diagnostic (OBD). This means a non working
cylinder is stored with the cylinder number in the
DTC memory. This has an advantage in case of
a malfunction the trouble shooting procedure can
be started at a certain cylinder. Check the DTC
memory of the Engine Control Module (ECM)
before commencing trouble shooting.

Test conditions

No DTCs stored relating to any of the fuel
injectors
Determine a non working or misfiring cylinder as
follows:
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28-11

Power output stages for ignition coils,
checking


Note:

Power Output Stage -N122 (black connector)
activates the ignition coils for cylinder bank 1
(cylinders 1 to 3).
Power Output Stage 2 -N192 (brown connector)
activates the ignition coils for cylinder bank 2
(cylinders 4 to 6).

Checking activation of power output stages

- Disconnect harness connectors from all six fuel
injectors.

Note:
It is important to ensure that no fuel is injected
during the test as this would damage the catalytic
converter. The harness connectors on the fuel
injectors must therefore be disconnected.
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