VOLVO
ECM-640D - Turbocharger (TC) control system. Signal too low
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)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, 2007–2009Engine B5254T2 only
- Volvo XC90 (2003–)2005–2006Engine B5254T2, B6294T only
What does this fault code mean?
The engine control module checks the boost pressure by comparing the measured value from the boost pressure sensor, taken before the throttle, with the calculated value after the throttle. The fault code is set when the relationship between the two becomes wrong while turbo control is active. The signal is too low compared with the calculated value, so the measured boost pressure is below what the module expects.
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
- Faulty software in the engine control module
What you can do
- 1Check that the boost pressure sensor is correctly fitted and has not come loose
- 2Look for air leaks between the turbocharger and the throttle unit, especially in the hoses. Check for loose clamps and damaged hoses
- 3The crankcase ventilation non-return valve should sit in place and be free of any damage
- 4If no fault is found in the checks above, the boost pressure sensor is probably damaged and needs replacing. Have a workshop do this
- 5Have a workshop check whether the engine control module needs a software update, 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.