VOLVO
ECM-2B20 - Heated oxygen sensor (HO2S) bank 2, preheating. Signal missing
System
Engine Control Module (ECM)
Volvo models this fault code applies to
Applies to the following models:
1 modelS80 (1999–2006)
Show models by year and engine (1)
What does this fault code mean?
The fault code shows that the preheating of the oxygen sensor on bank 2 gives no signal. The module measures the signal both when preheating is switched on and when it is off, and a signal that is too low while preheating is off sets the code.
Possible causes
- Signal wire short-circuited to ground
- Contact resistance and oxidation
- Power feed from the system relay is interrupted
What you can do
- 1Check that the connector at the bank 2 oxygen sensor is secure and free from contact resistance and oxidation
- 2Make sure every connector in the circuit is fully seated in its position
- 3Start the engine and let it idle. With a diagnostic tool you can read the status of the bank 2 sensor fault
- 4Use a multimeter to check that the supply wire to the sensor has no open circuit and that the signal wire is not short-circuited to ground (the body)
- 5If the fault remains, have a workshop check the wiring and the sensor
Symptoms you may notice1
- The malfunction indicator lamp (MIL) comes on
What the fault can affect1
- Fuel trim control is switched off
General guidance for car owners. Diagnosis on the car can point to a different cause.