A8 Quattro Sedan V8-4.2L (BGK) (2006)
Voltage Supply, Checking
‹› The respective fuses of Oxygen Sensor (O2S) Behind Three Way Catalytic Converter (TWC) (G130) and Oxygen Sensor (O2S) 2 Behind Three
Way Catalytic Converter (TWC) (G131) must be OK:
‹› At certain operating points, the ECM "pulses" the Ground (GND) for oxygen sensor heating. This means that the Ground (GND) is constantly
switched on and off at these operating points. It is therefore possible that the voltage displayed on the portable multimeter (VAG1526) will
fluctuate.
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Connect portable multimeter (VAG1526) between terminal 1 (B+) and terminal 2 Ground (GND) of respective oxygen sensor connector.
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Operate starter briefly.(Do not let engine run longer than 2 minutes, because of malfunction entry)
Specified value: approx. battery voltage
If specified value is not obtained.
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Connect portable multimeter (VAG1526) between terminal 1 (B+) of respective oxygen sensor connector and engine Ground (GND).
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Operate starter briefly.(Do not let engine run longer than 2 minutes, because of malfunction entry)
Specified value: approx. battery voltage
If specified value is again not obtained.
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Check wire connection from terminal 1 of the respective oxygen sensor connector via fuse to Fuel Pump (FP) Relay (J17) for open circuit or short
circuit.
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If voltage supply is OK, check wire connection.