A8L Quattro Sedan V8-4.2L (BVJ) (2007)
Oxygen Sensor: Testing and Inspection
Oxygen Sensor Heaters After Catalytic Converter, Checking
Oxygen Sensor Heater after Catalytic Converter, Checking
Oxygen Sensor Heater 1 Behind Three Way Catalytic Converter
‹› When servicing terminals in harness connector of Oxygen Sensor (O2S) Behind Three Way Catalytic Converter (TWC) use only gold-plated
terminals.
Special tools, testers and auxiliary items required
‹› Multimeter.
‹› Wiring diagram.
Test requirements
‹› Fuse (SC7) OK.
‹› Battery voltage at least 12.5 volts.
‹› All electrical consumers such as, lights and rear window defroster, switched off.
‹› Vehicles with automatic transmission, shift selector lever into position " P" or "N".
‹› A/C switched off.
‹› Ground (GND) connections between engine/transmission/chassis OK.
‹› Ignition switched off.
Test procedure
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Perform a preliminary check to verify the customers complaint. Refer to => [ Preliminary Check ] See: Powertrain Management/Computers and
Control Systems/Testing and Inspection/Scan Tool Testing and Procedures/Preliminary Check.
Start diagnosis
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Remove the rear engine cover - arrows -.
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Remove the vacuum lines - 3 - and - 4 - from the air guide hose.
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Disconnect the Mass Air Flow (MAF) Sensor (G70) electrical harness connector - 1 -.