VOLVO
ECM-123B - Air mass. Signal too high
System
Engine Control Module (ECM)
Volvo models this fault code applies to
Applies to the following models:
4 modelsC30 (2007–2013), C70 (2006–2013), S40 (2004–2013), V50 (2004–2013)
Show models by year and engine (9)
- 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 V50 (2004–2013)2005–2007Engine B5254T3 only
- Volvo V50 (2004–2013)2008–2012Engine B5254T7 only
What does this fault code mean?
The engine control module has found the air mass correction value rising too far, while the lambda adaptation sits outside a set range. The code is then set. The fault may come from poor contact, a leak in the intake, a blocked intake or a damaged air mass sensor.
Possible causes
- Oxidation and contact resistance in the connectors of the mass air flow sensor
- Air leakage in the intake system
- Blocked intake system
- Damaged mass air flow sensor
What you can do
- 1Clean the contacts at the mass air flow sensor connector and check for play, contact resistance and oxidation
- 2Check the hoses and joints between the mass air flow sensor and the throttle unit for leaks and damage
- 3Look for contamination in the throttle housing and clean it if needed
- 4If the fault remains, have a workshop check the mass air flow sensor
Symptoms you may notice1
- The malfunction indicator lamp comes on
What the fault can affect3
- Boost pressure is calculated instead of measured
- Rear oxygen sensor control is switched off
- Misfire detection is switched off
General guidance for car owners. Diagnosis on the car can point to a different cause.