VOLVO
ECM-641A - Camshaft control, exhaust. Faulty signal
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:
8 modelsC70 Cabriolet (1998–2005), S40 (2004–2013), S60 (2001–2009), S80 (1999–2006), V50 (2004–2013), V70 (2000–2008), V70 XC / XC70 (2001–2007), XC90 (2003–)
Show models by year and engine (15)
- Volvo C70 Cabriolet (1998–2005)2003–2005
- Volvo S40 (2004–2013)2004Engine B5254T3 only
- 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)2002Engine B5204T5, B5234T7, B5244T3, B6294T only
- Volvo S80 (1999–2006)2003Engine B5204T5, B5234T7, B5244T3, B5254T2, B6294T only
- Volvo S80 (1999–2006)2004Engine B5204T5, B5234T7, B5254T2, B6294T only
- Volvo V50 (2004–2013)2004Engine B5254T3 only
- Volvo V70 (2000–2008)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)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 engine control module checks that the exhaust camshaft is in the position requested in relation to the crankshaft. The deviation allowed before the fault code is set varies with engine conditions. The fault shows up as poor performance, hesitation under throttle and starting problems.
Possible causes
- Faulty control of the exhaust camshaft
- Low oil pressure
- Oil of poor quality
- Broken reset valve
- Mechanical fault in the VVT unit
- Valve that sticks
What you can do
- 1A blown fuse in the supply to the exhaust camshaft reset valve can cause the fault code, so check that first
- 2Check the engine oil level and quality. If these are in order, a workshop should check the oil pressure
- 3With a diagnostic tool, read the actual exhaust camshaft position and target value in live data while the engine is revved
- 4Start the camshaft control quick test in the diagnostic tool and see whether the exhaust camshaft follows different targets
- 5Have a workshop remove the reset valve, clean it and check the oil passages. Replace the valve if the fault remains
Symptoms you may notice5
- Malfunction indicator lamp (MIL) lit
- The engine’s fault indicator (Check engine) lights up or behaves abnormally
- Starting problems, with the starter motor cranking slowly
- Lack of power and poor performance
- The engine hesitates, surges or runs unevenly
What the fault can affect1
- Control of the exhaust camshaft is switched off
General guidance for car owners. Diagnosis on the car can point to a different cause.