VOLVO
ECM-2B2A - Rear lambda probe pre-heating, bank 2. Faulty signal. Intermittent fault.
System
Engine Control Module (ECM)
Volvo models this fault code applies to
This fault code has different meanings depending on model, model year or engine. Select the meaning that applies to your car.
Applies to the following models:
1 modelS80 (1999–2006)
Show models by year and engine (2)
What does this fault code mean?
The rear oxygen sensor on bank 2 has registered a faulty signal from the preheating. The fault is intermittent, meaning it comes and goes. It has been present, but is not present right now.
Possible causes
- Contact resistance and oxidation in the connections
- Signal wire short-circuited to ground
- Defective rear oxygen sensor on bank 2
What you can do
- 1Read and note the code, clear it and road test to see whether it returns
- 2Check that the connector at the bank 2 oxygen sensor is secure and free from contact resistance and oxidation
- 3Look for chafing on the sensor wiring, especially where it can move, and check that it is not shorted to ground
- 4If you have a diagnostic tool: during a road test, read the status of the bank 2 sensor heater in live data and see whether it drops out
- 5If the fault returns, have a workshop check 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.