Heated Oxygen Sensor (HO2S) Inspection for A4 Quattro
Specified value: 1.5 ohms max.
If the specification was not obtained:
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Check the wiring for a open circuit or short to Ground (GND).
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Check the electrical harness connector for damage, corrosion, loose or broken terminals.
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If necessary, repair the faulty wiring connection.
If no malfunction is detected in the wiring and if the voltage supply was OK:
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Erase the DTC memory. Refer to => [ Diagnostic Mode 04 - Erase DTC Memory ] See: Testing and Inspection/Scan Tool Testing and
Procedures/Diagnostic Modes 01 - 09
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Perform a road test to verify repair.
If the DTC does not return:
Generate readiness code. Refer to => [ Readiness Code ] See: Testing and Inspection/Monitors, Trips, Drive Cycles and Readiness Codes.
If the DTC does return and no malfunction is detected in the wiring and the voltage supply was OK:
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Replace the Engine Control Module (ECM) (J623 ).
Final procedures
After repair work, the following work steps must be performed in the following sequence:
1. Check the DTC memory. Refer to => [ Diagnostic Mode 03 - Read DTC Memory ] See: Testing and Inspection/Scan Tool Testing and
Procedures/Diagnostic Modes 01 - 09.
2. If necessary, erase the DTC memory. Refer to => [ Diagnostic Mode 04 - Erase DTC Memory ] See: Testing and Inspection/Scan Tool Testing
and Procedures/Diagnostic Modes 01 - 09.
3. If the DTC memory was erased, generate readiness code. Refer to => [ Readiness Code ] See: Testing and Inspection/Monitors, Trips, Drive
Cycles and Readiness Codes.