Checking wiring

WARNING: This page is about a different car, the 2004 Volvo S40, 2003 Volvo S40, 2002 Volvo S40, 2001 Volvo S40, and 2000 Volvo S40. However, it is still accessible from the selected car via links, so may be relevant.

Check the engine control module (ECM) and heated oxygen sensor (HO2S) connectors. Check for contact resistance and oxidation according to Contact resistance and oxidation .

Check in particular for damage or loose terminal pins.

Check the ground lead between engine control module (ECM) terminal #75 and heated oxygen sensor (HO2S) terminal #3. Check for an intermittent open-circuit according to Open-circuit, intermittent faults . Remedy if necessary.

Check the signal cable between engine control module (ECM) terminal #45 and heated oxygen sensor (HO2S) terminal #4. Check for an intermittent open-circuit according to Open-circuit, intermittent faults . Remedy if necessary.

Try a new heated oxygen sensor (HO2S) if no fault is found in the above fault-tracing.

Other information

To connect the breakout box, see Connecting the breakout box. EMS 2000
To replace the heated oxygen sensor (HO2S), see Replace the front heated oxygen sensor (HO2S) .

Fig 1: Identifying Heated Oxygen Sensor Connector Terminals

Courtesy of VOLVO CARS OF NORTH AMERICA.

Fig 2: Identifying Ohmmeter

Courtesy of VOLVO CARS OF NORTH AMERICA.

Fig 3: EMS2000

Courtesy of VOLVO CARS OF NORTH AMERICA.

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