R8 Quattro Coupe V10-5.2L (BUJ) (2010)
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Main Relay (Computer/Fuel System): Testing and Inspection
Voltage Supply, Checking
Voltage Supply, Checking
The Motronic Engine Control Module (ECM) Power Supply Relay (J271) supplies voltage to the Motronic Engine Control Module (ECM) (J623) and
the Engine Control Module (ECM) 2 (J624).
Special tools, testers and auxiliary items required
‹› Multimeter.
‹› Wiring diagram.
Test requirements
‹› The fuse (S133) fuse OK.
‹› Battery voltage at least 12.5 volts.
‹› All electrical consumers such as, lights and rear window defroster, switched off.
‹› Vehicles with automatic transmission, selector lever in position " P" or "N".
‹› A/C switched off.
‹› Ground (GND) connections between engine/transmission/chassis OK.
‹› Ignition switched off.
Test Procedure
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Perform a preliminary check to verify the customers complaint. Refer to => [ Preliminary Check ] See: Computers and Control Systems/Testing
and Inspection/Scan Tool Testing and Procedures/Preliminary Check
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Remove the Motronic Engine Control Module (ECM) Power Supply Relay (J271).
Checking voltage
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Using a Multimeter, check the Motronic Engine Control Module (ECM) Power Supply Relay (J271) socket 2/30 to Ground (GND).
Specified value: battery voltage.
If the specified value was not obtained:
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Check the wiring connections from the Battery to the Motronic Engine Control Module (ECM) Power Supply Relay (J271) socket 2/30 for an
open or short circuit.
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Check the wiring connections for damage, corrosion, lose or broken terminals.
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If necessary, repair the faulty wiring connection.
If the specified value was obtained:
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Using a Multimeter, check the Motronic Engine Control Module (ECM) Power Supply Relay (J271) socket 4/86 to Ground (GND).
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Switch the ignition on.
Specified value: battery voltage.
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Switch the ignition off.
If the specified value was not obtained:
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Check the wiring connections from the Battery to the Motronic Engine Control Module (ECM) Power Supply Relay (J271) socket 4/86 for an
