Checking the components and wiring

Check the heated oxygen sensor (HO2S) connector. Check for contact resistance and oxidation.

Check the cable between engine control module (ECM) terminal #A28 (#A28) and heated oxygen sensor (HO2S) terminal #2. Check for an open-circuit.

Try a new heated oxygen sensor (HO2S) if the above fault-tracing does not remedy the fault.

Remedy as necessary.

Other information 

• See Connecting the breakout box
• For information about signals on 5 cylinder engines, see Signal description or Signal specification
• See Heated oxygen sensor (HO2S), replacing
• See Contents

Fig 1: Identifying Front Heated Oxygen Sensor Connector Terminals

Courtesy of VOLVO CARS OF NORTH AMERICA.

Fig 2: Identifying VCT2000 Diagnostic Tool

Courtesy of VOLVO CARS OF NORTH AMERICA.

Fig 3: Identifying Front Heated Oxygen Sensor

Courtesy of VOLVO CARS OF NORTH AMERICA.

• Continue 

  Refer to Verification