A8 Quattro Sedan V8-4.2L (BVJ) (2008)
Specified value: Battery voltage.
Switch the ignition off.
If the specification was not obtained:
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Check the electrical harness connector for damage, corrosion, lose or broken terminals.
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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 a short circuit to each other, Ground (GND), or an open circuit.
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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, Removing and Installing ] See: Powertrain
Management/Computers and Control Systems/Engine Control Module/Service and Repair.
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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 an open circuit.