VOLVO
ECM-24EB - Rear heated oxygen sensor (HO2S). Slow regulation
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)2006–2007Engine B5254T3 only
- Volvo S40 (2004–2013)2008Engine B5254T3, B5254T7 only
- Volvo S40 (2004–2013)2009–2012Engine B5254T7 only
- Volvo V50 (2004–2013)2006–2007Engine B5254T3 only
- Volvo V50 (2004–2013)2008–2012Engine B5254T7 only
What does this fault code mean?
The engine control module (ECM) follows the signal from the rear oxygen sensor. If the sensor responds too sluggishly when the fuel/air mixture changes, the module treats this as a fault and stores the code.
Possible causes
- Contact resistance or oxidation in the connectors
- Damaged rear oxygen sensor
What you can do
- 1Read and note the code, clear it and road test to see whether it returns
- 2Check the rear oxygen sensor connector for contact resistance and oxidation, and correct any problems. Rust solvent spray and grease must not be used
- 3If the connector is clean but the fault remains, have a workshop try a new rear oxygen sensor
Symptoms you may notice1
- The malfunction indicator lamp (MIL) is lit
General guidance for car owners. Diagnosis on the car can point to a different cause.