VOLVO
ECM-0036 - Rear heated oxygen sensor (HO2S), bank 1 heating. Faulty signal
System
Engine Control Module (ECM)
Volvo models this fault code applies to
Applies to the following models:
3 modelsC30 (2007–2013), S40 (2004–2013), V50 (2004–2013)
What does this fault code mean?
The engine control module (ECM) keeps track of the heater in the rear oxygen sensor on bank 1. If the voltage in the heater circuit is incorrect, the ECM treats it as a fault. It is most often caused by the signal wire shorting to supply voltage or to ground, but the sensor itself may also be damaged.
Possible causes
- Signal wire shorted to supply voltage
- Signal wire shorted to ground
- Damaged rear oxygen sensor
What you can do
- 1With the ignition off, unplug the rear oxygen sensor connector and check the contacts for looseness, contact resistance and oxidation
- 2With the ignition on and the connector unplugged, use a multimeter to check whether the signal wire has voltage to ground; voltage there points to a short to supply voltage
- 3If the fault remains after erasing codes and a test drive, although the wiring is sound, have a workshop check and replace the rear oxygen sensor if needed
Symptoms you may notice1
- Malfunction indicator lamp (MIL) lights up
General guidance for car owners. Diagnosis on the car can point to a different cause.