VOLVO
ECM-305D - Knock control. Internal fault
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 control module has found a fault in its internal knock control circuit. The fault is in the control module itself, not in a knock sensor or the wiring. The fault may be temporary or lasting. The engine warning lamp may light, and ignition is controlled with a safety margin until the fault is repaired.
Possible causes
- Damaged control module
What you can do
- 1Clear the fault code and drive the car briefly to see whether the fault returns
- 2Check the battery and that the ground connections are secure, since interference at start-up can cause temporary faults
- 3Have a workshop replace the control module if the fault returns or remains
Symptoms you may notice2
- Poor performance
- Engine warning lamp lit
What the fault can affect1
- Ignition advance is pulled back to protect the engine
General guidance for car owners. Diagnosis on the car can point to a different cause.