VOLVO
ECM-2240 - Rear heated oxygen sensors (HO2S), switched. Faulty signal
System
Engine Control Module (ECM)
Volvo models this fault code applies to
Applies to the following models:
5 modelsS60 (2001–2009), S80 (1999–2006), V70 (2000–2008), V70 XC / XC70 (2001–2007), XC90 (2003–)
Show models by year and engine (10)
- Volvo S60 (2001–2009)2005–2006Engine B5204T5, B5244T4, B5244T5, B5254T2, B5254T4 only
- Volvo S80 (1999–2006)2005–2006Engine B5204T5, B5244T4, B5254T2, B6294S2, B6294T only
- Volvo V70 (2000–2008)2005Engine B5204T5, B5244T4, B5244T5, B5254T2, B5254T4 only
- Volvo V70 (2000–2008)2006Engine B5204T5, B5244T5, B5254T2, B5254T4 only
- Volvo V70 XC / XC70 (2001–2007)2005All engines except: D5244T
- Volvo V70 XC / XC70 (2001–2007)2006Engine B5244T4, B5254T2 only
- Volvo XC90 (2003–)2005–2006Engine B5254T2, B6294T only
- Volvo XC90 (2003–)2007–2012Engine B5254T2 only
- Volvo XC90 (2003–)2013–2014Engine B5254T9 only
- Volvo XC90 (2003–)2015
What does this fault code mean?
The engine control module (ECM) has detected that the two rear oxygen sensors have been swapped between bank 1 and bank 2. This can happen if the sensors were fitted incorrectly after service, but the fault can also be set if both sensors are damaged. The fault is diagnosed once the engine has been idling for a while.
Possible causes
- The rear oxygen sensors are fitted in the wrong bank
- Both rear oxygen sensors are damaged
What you can do
- 1Visually check that the rear oxygen sensors are not swapped between bank 1 and bank 2
- 2If you have a diagnostic tool: read the voltage of each rear oxygen sensor in live data with the engine idling and compare them with each other
- 3Check that the connectors to both sensors are secure and free from oxidation
- 4If the fault remains with the sensors correctly fitted, have a workshop decide whether the sensors need replacing
Symptoms you may notice1
- Malfunction indicator lamp (MIL) lit
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.