Checking wiring and components

Check signal cable (+) between control module #A42 and heated oxygen sensor (HO2S) connector terminal 4 for an open-circuit according to Open-circuit, permanent faults .

HINT: With the ignition on and heated oxygen sensor (HO2S) connector disconnected, the voltage between terminal 4 and ground terminal should be approximately 3.8 V. 

Check signal cable (-) between control module #A41 and heated oxygen sensor (HO2S) connector terminal 3 for an open-circuit according to Open-circuit, permanent faults .

If wiring is OK, try another heated oxygen sensor (HO2S).

Remedy as necessary.

Other information 

• Connecting the breakout box/accessing the control module, see Replacing the engine control module (ECM)
• To access/replace the heated oxygen sensor (HO2S), see Heated oxygen sensor (HO2S), replacing
• For information about signals, see Signal specification .

Fig 1: Identifying Heated Oxygen Sensor Terminal Connectors

Courtesy of VOLVO CARS OF NORTH AMERICA.

Fig 2: Identifying Voltmeter

Courtesy of VOLVO CARS OF NORTH AMERICA.

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  Refer to Verification