VOLVO
ECM-24CC - Front heated oxygen sensor (HO2S), bank 1. Signal too high
System
Engine Control Module (ECM)
Volvo models this fault code applies to
Applies to the following models:
4 modelsC30 (2007–2013), C70 (2006–2013), S40 (2004–2013), V50 (2004–2013)
Show models by year and engine (9)
- Volvo C30 (2007–2013)2007Engine B5254T3 only
- Volvo C30 (2007–2013)2008–2013Engine B5254T7 only
- Volvo C70 (2006–2013)2006–2007Engine B5254T3 only
- Volvo C70 (2006–2013)2008–2013Engine B5254T7 only
- Volvo S40 (2004–2013)2005–2007Engine B5254T3 only
- Volvo S40 (2004–2013)2008Engine B5254T3, B5254T7 only
- Volvo S40 (2004–2013)2009–2012Engine B5254T7 only
- Volvo V50 (2004–2013)2005–2007Engine B5254T3 only
- Volvo V50 (2004–2013)2008–2012Engine B5254T7 only
What does this fault code mean?
The ECM compares the front and rear oxygen sensors with each other and with their learned correction values. If the front sensor shows a lean mixture while the rear one shows a rich one, or the values drift too far apart, the code is stored. The fault can lie in the front or rear sensor circuit, and an exhaust leak can cause it.
Possible causes
- Leakage in the exhaust system
- Oxygen sensor gives an incorrectly lean signal
- Damaged oxygen sensor
What you can do
- 1Read and note the code, clear it and road test to see whether it returns
- 2Look for air leaks in the exhaust system, such as cracks and leaking joints
- 3Look at the oxygen sensor connectors for oxidation and loose connections
- 4If there is no leak, have a workshop try replacing the oxygen sensors, since a damaged front or rear sensor can also cause the fault
Symptoms you may notice1
- The malfunction indicator lamp (MIL) is 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.