VOLVO
ECM-0324 - Knock sensor (KS). Faulty signal
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)
What does this fault code mean?
The engine control module (ECM) monitors the knock sensor, which detects when combustion becomes irregular and the engine starts to knock. When the knock sensor gives signals that the control module cannot rely on, this is interpreted as a fault. The fault is checked while driving and is usually not noticed by the driver.
Possible causes
- Open circuit in the signal wire from the knock sensor
- Signal wire short-circuited to ground
- Signal wire short-circuited to supply voltage
- Damaged knock sensor
- Damaged engine control module
What you can do
- 1Read out the fault code, erase it and road-test to see whether it returns
- 2Switch off the ignition and unplug the knock sensor connector. Check the connector for looseness, contact resistance and oxidation
- 3Use a multimeter to check that the signal wire from the knock sensor has no open circuit and is not shorted to ground
- 4Also check that the signal wire is not shorted to voltage, for example where the cable may have rubbed against the body
- 5If you have a diagnostic tool, read the knock sensor signal in live data while the engine runs and see whether the value changes when the engine is under load
- 6If the fault remains, have a workshop with diagnostic equipment decide whether the knock sensor or the control module is at fault
Symptoms you may notice1
- No noticeable symptoms for the driver
General guidance for car owners. Diagnosis on the car can point to a different cause.