S4 Quattro Cabriolet V8-4.2L (BHF) (2008)
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Disconnect the Oxygen Sensor (O2S) Heater (Z19 ) for Heated Oxygen Sensor (HO2S) (G39) electrical harness connector - 1 -.
Checking internal resistance
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Using a multimeter, check the Heated Oxygen Sensor (HO2S) terminals 6 to 3 for an open circuit.
Specified value: 2.5 to 10.0 ohms (at approx. 20° C)
If the specification was not obtained:
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Replace the Heated Oxygen Sensor (HO2S) (G39) or the Heated Oxygen Sensor (HO2S) 2 (G108) Refer to Fuel Injection and Ignition Repair
Information.
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 3 to ground (GND) for voltage.