S5 Quattro Coupe V8-4.2L (CAUA) (2009)
If the specification was not obtained:
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Replace Heated Oxygen Sensor (HO2S) 2 (G108).
If the specification was obtained:
Checking voltage supply
Crank the engine.
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Using a multimeter, check the Heated Oxygen Sensor (HO2S) 2 (G108) electrical harness connector terminal 4 to Ground (GND) for voltage.
Specified value: Battery voltage.
Switch the ignition off.
If the specification was not obtained:
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Check the wiring from the Heated Oxygen Sensor (HO2S) 2 (G108) electrical harness connector terminal 4 to the Engine Component Power
Supply Relay (J757) socket 2/87 for an open circuit, a short circuit to Battery (+), or 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 faulty wiring connection.
If the specification was obtained:
Checking Ground (GND) activation
If the manufacturers test box is being used, perform the following step.
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Install the test box.
If the manufacturers test box is not being used, perform the following step.
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Remove the Motronic Engine Control Module (ECM) (J623). Refer to => [ Engine Control Module, Replacing ] See: Engine Control
Module/Service and Repair/Engine Control Module, Replacing.
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Using a multimeter, check the Heated Oxygen Sensor (HO2S) 2 (G108) electrical harness connector to the Motronic Engine Control Module
(ECM) (J623) electrical harness connector T94 for resistance.