S5 Quattro Coupe V8-4.2L (CAUA) (2009)
Oxygen Sensor: Testing and Inspection
Heated Oxygen Sensor 2 before Catalytic Converter, Checking
Heated Oxygen Sensor 2 before Catalytic Converter, Checking
‹› Oxygen Sensor (O2S) 2 Heater (Z28) is part of Heated Oxygen Sensor (HO2S) 2 (G108) and cannot be serviced separately.
‹› When servicing terminals in the electrical harness connector of Heated Oxygen Sensor (HO2S) 2 (G108), use only gold-plated terminals.
Special tools, testers and auxiliary items required
‹› Multimeter.
‹› Wiring diagram.
Test requirements
‹› Fuse (SB10) 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: Computers and Control Systems/Testing
and Inspection/Scan Tool Testing and Procedures/Preliminary Check.
Start diagnosis
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Remove the engine compartment trim.
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Remove the engine cover - 2 -.
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Remove the air filter housing bolts - arrows -.
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Remove the air guide hoses - 1 - and - 6 - from the air filter housing.