VOLVO
ECM-641F - Camshaft reset valve, 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:
3 modelsS60 (2001–2009), S80 (1999–2006), V70 (2000–2008)
What does this fault code mean?
During fuel cut-off, for example when driving downhill with the throttle closed, the engine control module carries out an adaptation of the exhaust camshaft reset valve. The module then checks that the valve reaches its end positions. If they are not reached, this is treated as a fault and the fault code is stored. The fault can be caused by a faulty signal, a loose camshaft sensor or an incorrect base setting of the timing belt.
Possible causes
- Faulty signal
- Loose camshaft sensor
- Incorrect base setting of the timing belt
What you can do
- 1The markings on the engine show whether the timing belt is correctly positioned relative to the camshafts. If not, a workshop should adjust it
- 2Check that the camshaft sensor connector is secure and clean, since a loose sensor can cause a signal fault
- 3Have a workshop clean the reset valve, since contamination can cause the fault
- 4Replace the reset valve if the fault remains after cleaning. Clear the fault code after the work
Symptoms you may notice3
- Reduced performance
- The engine misfires
- Uneven idle
What the fault can affect1
- The variable exhaust camshaft is switched off
General guidance for car owners. Diagnosis on the car can point to a different cause.