S5 Quattro Coupe V8-4.2L (CAUA) (2009)
Specified value: 12.5 V
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Switch the ignition off.
If the specified value was not obtained:
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Check the Motronic Engine Control Module (ECM) (J623) electrical harness connector 94 terminal 3, 5, 6 to the Motronic Engine Control
Module (ECM) Power Supply Relay (J271) socket 4 for an open circuit or short to Ground (GND).
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Check the electrical harness connectors for damage, corrosion, loose or broken terminals.
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If necessary, repair the wiring connection.
If no malfunctions are found in the wiring:
Checking Ground (GND)
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Using a Multimeter, check the following wiring connections for resistance.
Specified value: 1.5 ohms.
If any of the specified values are not obtained:
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Check the electrical harness connector for damage, corrosion, loose or broken terminals.
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If necessary, repair the wiring connection.
If no malfunctions are found in the wiring and the voltage supply was OK:
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Perform a road test to verify any electrical repairs.
If the fault does not return:
Repair complete, Generate readiness code. Refer to => [ Readiness Code ] See: Computers and Control Systems/Testing and Inspection/Monitors,
Trips, Drive Cycles and Readiness Codes.
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End of diagnosis.
If the fault does return and no malfunction is detected in the wiring and the voltage supply was OK:
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Replace the Engine Control Module (ECM) (J623). Refer to => [ Engine Control Module, Replacing ] See: Service and Repair/Engine Control
Module, Replacing.
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Assembly is performed in the reverse of the removal.