VOLVO
ECM-3420 - Knock sensor (KS) rear. Signal too low. Intermittent fault
System
Engine Control Module (ECM)
Volvo models this fault code applies to
This fault code has different meanings depending on model, model year or engine. Select the meaning that applies to your car.
Applies to the following models:
6 modelsC70 Cabriolet (1998–2005), S60 (2001–2009), S80 (1999–2006), V70 (2000–2008), V70 XC / XC70 (2001–2007), XC90 (2003–)
Show models by year and engine (17)
- Volvo C70 Cabriolet (1998–2005)2003–2005
- Volvo S60 (2001–2009)2001All engines except: B5244S, B5244S2, D5244T
- Volvo S60 (2001–2009)2002Engine B5204T5, B5234T3, B5234T7, B5244T3 only
- Volvo S60 (2001–2009)2003Engine B5204T5, B5234T3, B5234T7, B5244T3, B5254T2 only
- Volvo S60 (2001–2009)2004Engine B5204T5, B5234T3, B5234T7, B5254T2, B5254T4 only
- Volvo S80 (1999–2006)1999–2000All engines except: B5244S, B5244S2, D5252T MSA 15.8
- Volvo S80 (1999–2006)2001Engine B5204T5, B5234T7, B5244T3, B6284T, B6294S only
- Volvo S80 (1999–2006)2002Engine B5204T5, B5234T7, B5244T3, B6294S2, B6294T only
- Volvo S80 (1999–2006)2003Engine B5204T5, B5234T7, B5244T3, B5254T2, B6294S2, B6294T only
- Volvo S80 (1999–2006)2004Engine B5204T5, B5234T7, B5254T2, B6294S2, B6294T only
- Volvo V70 (2000–2008)2000All engines except: D5252T MSA 15.8
- Volvo V70 (2000–2008)2001–2002Engine B5204T5, B5234T3, B5234T7, B5244T3 only
- Volvo V70 (2000–2008)2003Engine B5204T5, B5234T3, B5234T7, B5244T3, B5254T2 only
- Volvo V70 (2000–2008)2004Engine B5204T5, B5234T3, B5234T7, B5254T2, B5254T4 only
- Volvo V70 XC / XC70 (2001–2007)2001–2002
- Volvo V70 XC / XC70 (2001–2007)2003–2004All engines except: D5244T
- Volvo XC90 (2003–)2003–2004All engines except: D5244T
What does this fault code mean?
The signal from the rear knock sensor is too low. The control module checks it against limits that depend on engine speed and load. The fault is stored as intermittent and may not be active at the moment.
Possible causes
- Contact resistance in the connectors
- Open circuit in the signal wire
- Defective knock sensor
- Short circuit between the knock sensor signal wires
What you can do
- 1If you have a diagnostic tool: read the fault status for the rear knock sensor; "No fault found" means the fault is not active at the moment
- 2Check the rear knock sensor connection: fastened, clean and free from oxidation
- 3Check that the connector locks properly and is not loose
- 4Check that the knock sensor is firmly tightened
- 5If the fault remains and the connection is sound, have a workshop replace the knock sensor with diagnostic equipment
Symptoms you may notice1
- No noticeable symptoms for the driver
What the fault can affect2
- Ignition timing is retarded for safety reasons
- Boost pressure is lowered
General guidance for car owners. Diagnosis on the car can point to a different cause.