A4 Quattro Cabriolet L4-2.0L Turbo (BWT) (2009)
Specified value: 12.5. battery voltage.
If the specified value was not obtained:
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Check the Engine Component Power Supply Relay ( J757) socket 3/T to the Motronic Engine Control Module (ECM) Power Supply Relay (J271)
socket 2/87 for an open circuit or short to Ground (GND).
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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:
Checking Ground (GND)
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Using a Multimeter, check the Engine Component Power Supply Relay (J757) socket 4/86 to the Engine Control Module (ECM) (J623) electrical
harness connector terminal T94/32 for resistance.
Specified value: 1.5 ohms.
If the specified value was not obtained:
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Check the Engine Component Power Supply Relay ( J757) socket 4/86 to the Engine Control Module (ECM) (J623) electrical harness connector
terminal T9432 for an open circuit or a short to Battery (+) or to Ground (GND).
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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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Replace the Engine Component Power Supply Relay ( J757).
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Perform a road test to verify repair.
If the fault does not return:
Repair complete, Generate readiness code. Refer to => [ Readiness Code ] See: Testing and Inspection/Monitors, Trips, Drive Cycles and Readiness
Codes.
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End 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: Engine Control Module/Service and
Repair.
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Assembly is performed in the reverse of the removal.
Final procedures
After repair work, the following work steps must be performed in the mentioned sequence:
1. Check the DTC memory. => [ Diagnostic Mode 03 - Read DTC Memory ] See: Testing and Inspection/Scan Tool Testing and
Procedures/Diagnostic Modes/Diagnostic Mode 03 - Read DTC Memory.
2. If necessary, erase the DTC memory. => [ Diagnostic Mode 04 - Erase DTC Memory ] See: Testing and Inspection/Scan Tool Testing and
Procedures/Diagnostic Modes/Diagnostic Mode 04 - Erase DTC Memory.
3. If the DTC memory was erased, generate readiness code. => [ Readiness Code ] See: Testing and Inspection/Monitors, Trips, Drive Cycles and
Readiness Codes.
End of diagnosis.