VOLVO
ECM-P209728 - Post Catalyst Fuel Trim System Too Rich Bank 1. General Signal Failures. Signal bias level out of range / zero adjustment failure
System
Engine Control Module (ECM)
Volvo models this fault code applies to
Applies to the following models:
6 modelsS60 (2011–), S80 (2007–), V40 (2013–), V40 Cross Country (2013–), V60 (2011–), V70 (2008–)
Show models by year and engine (11)
- Volvo S60 (2011–)2011Engine B4164T, B4164T3 only
- Volvo S60 (2011–)2012–2015Engine B4164T, B4164T2, B4164T3 only
- Volvo S80 (2007–)2011, 2015Engine B4164T only
- Volvo S80 (2007–)2012–2014Engine B4164T, B4164T2 only
- Volvo V40 (2013–)2013Engine B4164T, B4164T3 only
- Volvo V40 (2013–)2014–2015Engine B4164T, B4164T3, B4164T4 only
- Volvo V40 Cross Country (2013–)2013–2015Engine B4164T only
- Volvo V60 (2011–)2011Engine B4164T, B4164T3 only
- Volvo V60 (2011–)2012–2015Engine B4164T, B4164T2, B4164T3 only
- Volvo V70 (2008–)2011Engine B4164T only
- Volvo V70 (2008–)2012–2015Engine B4164T, B4164T2 only
What does this fault code mean?
Although the code is named signal bias or zero adjustment failure, it applies when the oxygen sensor shows a mixture that is wrongly rich compared with what the engine control module (ECM) expects. The fault may come from a leak in the exhaust system or from a damaged oxygen sensor.
Possible causes
- Leakage in the exhaust system
- Oxygen sensor indicates an incorrectly rich mixture
- Damaged oxygen sensor
What you can do
- 1Check the wiring to the oxygen sensor for damage and chafing
- 2Check the exhaust system for leaks, since a leak can give a wrong signal
- 3If you have a diagnostic tool: read the oxygen sensor signal in live data with the engine running steadily and see whether it shows a rich mixture
- 4If the fault remains, have a workshop establish whether the engine control module has an internal fault and, if so, replace it
Symptoms you may notice1
- Check engine warning lamp lights or behaves abnormally
What the fault can affect2
- Oxygen sensor control is switched off
- Catalytic converter diagnostics are switched off
General guidance for car owners. Diagnosis on the car can point to a different cause.