VOLVO
ECM-643A - Camshaft position, exhaust. Signal too low
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:
5 modelsC70 Cabriolet (1998–2005), S60 (2001–2009), S80 (1999–2006), V70 (2000–2008), V70 XC / XC70 (2001–2007)
Show models by year and engine (9)
- Volvo C70 Cabriolet (1998–2005)2003–2005
- Volvo S60 (2001–2009)2002–2003Engine B5204T5, B5234T3, B5234T7, B5244T3 only
- Volvo S60 (2001–2009)2004Engine B5204T5, B5234T3, B5234T7 only
- Volvo S80 (1999–2006)2002–2003Engine B5204T5, B5234T7, B5244T3 only
- Volvo S80 (1999–2006)2004Engine B5204T5, B5234T7 only
- Volvo V70 (2000–2008)2002–2003Engine B5204T5, B5234T3, B5234T7, B5244T3 only
- Volvo V70 (2000–2008)2004Engine B5204T5, B5234T3, B5234T7 only
- Volvo V70 XC / XC70 (2001–2007)2002
- Volvo V70 XC / XC70 (2001–2007)2003–2004Engine B5234T7 only
What does this fault code mean?
The engine control module has registered that the signal for the exhaust camshaft position is too low. The fault may be caused by poor oil quality, incorrectly adjusted camshafts, a timing belt that has jumped over the teeth, or a mechanical fault in the VVT unit.
Possible causes
- Poor oil quality
- Incorrectly adjusted camshafts
- The timing belt has jumped over the teeth
- Defective reset valve
- Mechanical fault in the VVT unit
What you can do
- 1Start the engine and let it warm up. Read the camshaft adaptation at idle with a diagnostic tool. A value outside the normal range points to a permanent fault
- 2Check the engine oil level and quality, and look for contamination in the oil
- 3If the camshafts are incorrectly adjusted, a workshop needs to adjust them to the crankshaft
- 4Have a workshop check that the timing belt has not jumped over the teeth
Symptoms you may notice1
- The malfunction indicator lamp (MIL) lights
General guidance for car owners. Diagnosis on the car can point to a different cause.