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Home >> Volvo >> 2004 >> S80 Base, 2.5 59, FWD >> Repair and Diagnosis >> Engine Performance >> System >> Engine Control Module (ECM) Diagnostic Trouble Codes - 4 Of 11 >> ECM-280A: Front Heated Oxygen Sensor (Ho2S), Bank 1. Signal Too High. Intermittent Fault (B5254T2; 2004) >> Signal too high >> Checking components and wiring >> Notes
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Checking components and wiring: Notes

CAUTION:

Do not apply rust solvent spray or grease to the heated oxygen sensor (HO2S) connector.

HINT: The fault may be caused by a fault in the circuit for the rear heated oxygen sensor (HO2S). 

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

Check the signal cable (+) between heated oxygen sensor (HO2S) terminal #4 and control module terminal #A61 (#B1). Check the signal cable (-) between heated oxygen sensor (HO2S) terminal #3 and control module terminal #A62 (#B2). Check for an open-circuit. Check for a short-circuit to ground. Check for a short-circuit to supply voltage.

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

Remedy as necessary.

Other information 

Fig 1: Identifying Rear Heated Oxygen Sensor (HO2S) Connector
GLL104129Courtesy of VOLVO CARS OF NORTH AMERICA.
Fig 2: Identifying Voltage Display
GLL101041Courtesy of VOLVO CARS OF NORTH AMERICA.
Fig 3: Identifying Rear Heated Oxygen Sensor (HO2S)
GLL102933Courtesy of VOLVO CARS OF NORTH AMERICA.