VOLVO
ECM-0137 - Rear heated oxygen sensor (HO2S), bank 1. Signal too low
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 has detected that the signal from the rear lambda sensor on bank 1 is below a set limit and treats this as a fault. The rear sensor is used to check that the catalytic converter works, so a signal that is too low means the sensor's reading is not right. The fault is most often a signal wire shorted to ground, or a damaged sensor.
Possible causes
- Signal wire shorted to ground
- Damaged rear lambda sensor, bank 1
What you can do
- 1Read, note and clear the code, then road test to see whether it returns
- 2Check that the connector at the rear lambda sensor is fully engaged and free from corrosion
- 3Follow the signal wire from the sensor and look for chafing and pinched sections, especially where it runs near the exhaust pipe
- 4With the connector unplugged, use a multimeter to check that the signal wire has no connection to ground (the body)
- 5With a diagnostic tool, a rear sensor value that stays constantly low points to a signal fault
- 6If the fault returns, have a workshop with diagnostic equipment check the wiring and decide whether the sensor should be replaced
Symptoms you may notice1
- Malfunction indicator lamp (MIL) lit
General guidance for car owners. Diagnosis on the car can point to a different cause.