Checking Components And Wiring

Check the signal cable (+) between heated oxygen sensor (HO2S) terminal #1 and control module terminal #A43 (#A43). Check the signal cable (-) between heated oxygen sensor (HO2S) terminal #5 control module terminal #A44 (#A44). Check for a short-circuit to each other.

Check the power supply to heated oxygen sensor (HO2S) terminal #3. Check the signal cable between heated oxygen sensor (HO2S) terminal #4 and control module terminal #A17 (#A17). Check for a short-circuit to the other wiring for the heated oxygen sensor (HO2S).

Try a new heated oxygen sensor (HO2S) if the wiring is OK.

Remedy as necessary.

Other information: 

• To connect the breakout box / access the control module, see CONNECTING THE BREAKOUT BOX
• For B5xx4T, see HEATED OXYGEN SENSOR (HO2S), REPLACING
• For B6xx4T, see HEATED OXYGEN SENSOR (HO2S), REPLACING .
• For 6 cylinder engines -2004, see SIGNAL SPECIFICATION
• For 6 cylinder engines 2005-, see SIGNAL SPECIFICATION .
• see CHECKING WIRING AND TERMINALS .

Fig 1: Identifying Front Heated Oxygen Sensor (HO2S) Connector Terminals

Courtesy of VOLVO CARS CORPORATION

Fig 2: Identifying Ohm Meter

Courtesy of VOLVO CARS CORPORATION

Fig 3: Identifying Front Heated Oxygen Sensor (HO2S)

Courtesy of VOLVO CARS CORPORATION

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  Refer to VERIFICATION