R8 Quattro Coupe V10-5.2L (BUJ) (2010)
Main Relay (Computer/Fuel System): Testing and Inspection
Engine Component Power Supply Relay, Checking
Engine Component Power Supply Relay, Checking
Special tools, testers and auxiliary items required
‹› multimeter.
‹› wiring diagrams.
Test requirements
‹› Fuse (SD1) OK.
‹› The Engine Control Module Power Supply Relay (J271) OK.
‹› The Ground (GND) connections at the engine and transmission OK.
‹› The battery voltage at least 12.5 V.
‹› The generator OK.
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.
Start diagnosis
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Using a multimeter, check the following wiring connection for voltage.
Specified value: 12.5 V
If the specified value was not obtained:
-
Check the Engine Component Power Supply Relay (J757) socket 2 to the Battery (A) positive terminal 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.
-
If necessary, repair the wiring connection.
If no malfunctions are found in the wiring:
-
Switch the engine on.
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Using a multimeter, check the following wiring connection for voltage.
Specified value: 12.5 V
-
Switch the engine off.
If the specified value was not obtained:
-
Check the Engine Component Power Supply Relay (J757) socket 8/87 to Fuse 3 (on fuse panel C) (SC3)\ for an open circuit or short to Ground
(GND).