VOLVO
ECM-126B - Boost pressure sensor. Signal missing
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 modelsS60 (2001–2009), S80 (1999–2006), V70 (2000–2008), V70 XC / XC70 (2001–2007), XC90 (2003–)
Show models by year and engine (14)
- 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)2005–2006Engine B5204T5, B5244T4, B5254T2, B6294S2, B6294T 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 (2000–2008)2008Engine B5254T2 only
- Volvo V70 XC / XC70 (2001–2007)2005All engines except: D5244T
- Volvo V70 XC / XC70 (2001–2007)2006Engine B5244T4, B5254T2 only
- Volvo V70 XC / XC70 (2001–2007)2007Engine B5254T2 only
- Volvo XC90 (2003–)2005–2006Engine B5254T2, B6294T only
- Volvo XC90 (2003–)2007–2012Engine B5254T2 only
- Volvo XC90 (2003–)2013–2014Engine B5254T9 only
- Volvo XC90 (2003–)2015
What does this fault code mean?
The engine control module (ECM) compares the signal from the boost pressure sensor with a value it calculates from the atmospheric pressure sensor. Even though the fault says the signal is missing, the signal itself is within its normal range, only lower than expected. The fault is checked with the ignition on and the engine running, and it can limit boost pressure so the car feels weaker.
Possible causes
- Contact resistance or oxidation in the boost pressure sensor connector
- Loose boost pressure sensor
- Damaged boost pressure sensor
What you can do
- 1Read the fault code, clear it and test drive the car to see whether it returns
- 2Check that the boost pressure sensor connector is fully seated and free from corrosion and oxidation
- 3Check that the boost pressure sensor is properly fitted and that there are no air leaks in the hoses around it
- 4If you have a diagnostic tool: compare boost pressure in live data with atmospheric pressure, ignition on and engine off; the two values should be close
- 5If the connector and sensor look fine, have a workshop with diagnostic equipment check the sensor signal
Symptoms you may notice2
- Engine warning lamp comes on
- Noticeably reduced performance
What the fault can affect1
- Boost pressure is limited
General guidance for car owners. Diagnosis on the car can point to a different cause.