VOLVO
ECM-640C - Turbocharger (TC) control system. Signal too high
System
Engine Control Module (ECM)
Volvo models this fault code applies to
Applies to the following models:
9 modelsC30 (2007–2013), C70 (2006–2013), 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 (23)
- Volvo C30 (2007–2013)2007Engine B5254T3 only
- Volvo C30 (2007–2013)2008–2013Engine B5254T7 only
- Volvo C70 (2006–2013)2006–2007Engine B5254T3 only
- Volvo C70 (2006–2013)2008–2013Engine B5254T7 only
- Volvo S40 (2004–2013)2005–2007Engine B5254T3 only
- Volvo S40 (2004–2013)2008Engine B5254T3, B5254T7 only
- Volvo S40 (2004–2013)2009–2012Engine B5254T7 only
- Volvo S60 (2001–2009)2003–2004Engine B5254T2 only
- Volvo S60 (2001–2009)2005–2006Engine B5204T5, B5244T4, B5244T5, B5254T2, B5254T4 only
- Volvo S60 (2001–2009)2007Engine B5204T5, B5244T5, B5254T2, B5254T4 only
- Volvo S60 (2001–2009)2008–2009Engine B5204T5, B5244T5, B5254T2 only
- Volvo S80 (1999–2006)2003–2004Engine B5254T2 only
- Volvo S80 (1999–2006)2005–2006Engine B5204T5, B5244T4, B5254T2, B6294S2, B6294T only
- Volvo V50 (2004–2013)2005–2007Engine B5254T3 only
- Volvo V50 (2004–2013)2008–2012Engine B5254T7 only
- Volvo V70 (2000–2008)2003–2004, 2008Engine B5254T2 only
- Volvo V70 (2000–2008)2005Engine B5204T5, B5244T4, B5244T5, B5254T2, B5254T4 only
- Volvo V70 (2000–2008)2006–2007Engine B5204T5, B5244T5, B5254T2, B5254T4 only
- Volvo V70 XC / XC70 (2001–2007)2003–2004, 2007Engine B5254T2 only
- Volvo V70 XC / XC70 (2001–2007)2005All engines except: D5244T
- Volvo V70 XC / XC70 (2001–2007)2006Engine B5244T4, B5254T2 only
- Volvo XC90 (2003–)2003–2004, 2007–2011Engine B5254T2 only
- Volvo XC90 (2003–)2005–2006Engine B5254T2, B6294T only
What does this fault code mean?
The engine control module compares the measured boost pressure, taken before the throttle, with the calculated boost pressure after the throttle. If the ratio between the two becomes incorrect, the fault code is set. This means the signal from the boost pressure system is too high compared with the calculated value.
Possible causes
- Damaged boost pressure sensor
- Loose boost pressure sensor
- Air leak between the turbocharger and the throttle unit
- Large air leak in the intake manifold after the throttle unit
- Damaged non-return valve to the crankcase ventilation
- Software fault in the engine control module
What you can do
- 1Check that the boost pressure sensor is fully seated and has not come loose, and that its connector is clean and undamaged
- 2Look for air leaks in the intake system, especially the hose between the turbocharger and the throttle unit. Check for loose clamps and cracks
- 3Check that the crankcase ventilation non-return valve is fitted correctly and has no damage
- 4If no leak and no loose sensor is found, the boost pressure sensor is probably damaged. Have a workshop replace it and check the fault
- 5Have a workshop check whether a software update is available for the engine control module, since old software can cause this code
Symptoms you may notice1
- Poor performance
What the fault can affect1
- Boost pressure becomes lower than normal
General guidance for car owners. Diagnosis on the car can point to a different cause.