VOLVO
ECM-2338 - Cylinder #3 Above Knock Threshold
System
Engine Control Module (ECM)
Volvo models this fault code applies to
Applies to the following models:
3 modelsC30 (2007–2013), S40 (2004–2013), V50 (2004–2013)
Show models by year and engine (9)
- Volvo C30 (2007–2013)2008–2009Engine B4184S11, B4184S8, B4204S3 only
- Volvo C30 (2007–2013)2010Engine B4184S11, B4184S8, B4204S3, B4204S4 only
- Volvo C30 (2007–2013)2011–2013Engine B4204S3, B4204S4 only
- Volvo S40 (2004–2013)2008–2009Engine B4184S11, B4184S8, B4204S3 only
- Volvo S40 (2004–2013)2010Engine B4184S11, B4184S8, B4204S3, B4204S4 only
- Volvo S40 (2004–2013)2011–2012Engine B4204S3, B4204S4 only
- Volvo V50 (2004–2013)2008–2009Engine B4184S11, B4184S8, B4204S3 only
- Volvo V50 (2004–2013)2010Engine B4184S11, B4184S8, B4204S3, B4204S4 only
- Volvo V50 (2004–2013)2011–2012Engine B4204S3, B4204S4 only
What does this fault code mean?
The engine control module (ECM) registers knock in cylinder 3 and can pull back the ignition to stop it. The code is set when the number of knock events in that cylinder goes beyond what the module accepts. The knock sensor on the engine block is used to detect the knock.
Possible causes
- Engine running on a lean fuel/air mixture
- Poor fuel quality, for example summer fuel in winter
- Engine running too hot
- Intake air temperature too high
- Knock sensor fitted loosely
- Damaged knock sensor
What you can do
- 1Clear the code after reading it and road test; have someone listen for knock under acceleration
- 2Make sure the fuel suits the season, and change it if you have put in the wrong grade
- 3Check the knock sensor connector and make sure it has not come loose
- 4If you have a diagnostic tool: read the ignition timing adjustment for cylinder 3 in live data when the engine knocks
- 5If the fault remains after these checks, have a workshop decide whether the knock sensor should be replaced
Symptoms you may notice1
- Poor performance
General guidance for car owners. Diagnosis on the car can point to a different cause.