Checking the heated oxygen sensor (HO2S)

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.

Fig 1: Identifying Ignition OFF

Courtesy of VOLVO CARS OF NORTH AMERICA.

Fig 2: Disconnecting Connector

Courtesy of VOLVO CARS OF NORTH AMERICA.

Ignition off
Disconnect the connectors for the front (ECM-18) and rear (ECM-1C) heated oxygen sensor (HO2S).
Connect an ohmmeter between connector terminals 1 and 2 for the heated oxygen sensor (HO2S) (probe side).

Fig 3: Identifying Heated Oxygen Sensor (HO2S) Connector Terminals
Courtesy of VOLVO CARS OF NORTH AMERICA.

Fig 4: Identifying Ohmmeter
Courtesy of VOLVO CARS OF NORTH AMERICA.

The resistance should be 6-25 Ω depending on the temperature of the heated oxygen sensor (HO2S).

OK
Refer to Checking the signal cable
NOT OK
Refer to Defective heated oxygen sensor (HO2S)