Checking Connectors And Wiring

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

Check the signal cable (-) between heated oxygen sensor (HO2S) terminal #5 and control module terminal #A44 (#A44). Check the cable for calibration current between heated oxygen sensor (HO2S) terminal #2 and heated oxygen sensor (HO2S) terminal #A69 (#B9). Check for an intermittent open-circuit.

Check the cable for calibration current between heated oxygen sensor (HO2S) terminal #2 and control module terminal #A69 (#B9). Check the cable for pump current between heated oxygen sensor (HO2S) terminal #6 and control module terminal #A25 (#A25). Check for an intermittent short-circuit to each other.

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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