S4 Quattro Wagon V8-4.2L (BHF) (2008)
If the specification was obtained:
Checking voltage supply
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Using a multimeter, check the Heated Oxygen Sensor (HO2S) electrical harness connector terminal 1 to ground (GND) for voltage.
Specified value: Battery voltage.
If the specification was not obtained:
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Check the Heated Oxygen Sensor (HO2S) electrical harness connector terminal 1 to the Fuel Pump (FP) Relay ( J17) terminal 2 for an open
circuit.
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Check the wiring for a short circuit to each other, Battery (+), and Ground (GND).
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Check the electrical harness connector for damage, corrosion, lose 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. Refer to Fuel Injection and Ignition Repair Information.
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: Computers and Control
Systems/Engine Control Module/Service and Repair.
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Using a multimeter, check the Oxygen Sensor (O2S) Behind Three Way Catalytic Converter (TWC) electrical harness connector to the Motronic
Engine Control Module (ECM) (J623) electrical harness connector T121 for an open circuit.