Checking the connector

Check the connector for the rear heated oxygen sensor (HO2S). Check for contact resistance and oxidation. Remedy if necessary.

Try a new rear heated oxygen sensor (HO2S) if the above corrective action does not remedy the fault.

Other information 

• To access or replace the heated oxygen sensor (HO2S), see Heated oxygen sensor (HO2S), replacing
• See Checking wiring and terminals .

Fig 1: Identifying Rear Heated Oxygen Sensor

Courtesy of VOLVO CARS OF NORTH AMERICA.

• Continue 

  Refer to Verification