VOLVO
ECM-2297 - Front heated oxygen sensor (HO2S), bank 1. 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) monitors the front oxygen sensor. The code is set when the sensor gives too weak a signal while the engine brakes without fuel, that is at fuel cut-off. The code is tested only after the car has been driven with fuel cut-off, so the lamp may go out only part way into the next drive if the fault has cleared.
Possible causes
- Open circuit in the signal wire
- Signal wire short-circuited to ground
- Signal wire short-circuited to supply voltage
- Damaged front oxygen sensor
What you can do
- 1Read and clear the fault code, then road test with stretches where the engine brakes without throttle, for example on a downhill
- 2Check that the connector to the front oxygen sensor is secure and free from oxidation
- 3Use a multimeter to check that the signal wire has no break and is not shorted to ground or voltage, with the sensor connector unplugged
- 4If you have a diagnostic tool: look at the front oxygen sensor signal in live data during engine braking and see whether it drops sharply
- 5If the fault remains, have a workshop decide whether the front oxygen 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.