Q7 Quattro V8-4.2L (BAR) (2008)
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Using a multimeter, check the Heated Oxygen Sensor (HO2S) electrical harness connector terminal 3 to the Engine Component Power Supply
Relay (J757) terminal 2/87 for voltage.
Specified value: Battery voltage.
Switch the ignition off.
If the specification was not obtained:
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Check the wiring for a short circuit to each other, Ground (GND), or an Open circuit.
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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.
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) electrical harness connector to the Motronic Engine Control Module (ECM) (J623)
electrical harness connector T94 for an open circuit.
Specified value: 1.5 ohms max.