VOLVO
ECM-123C - 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)2006–2007Engine B5254T3 only
- Volvo S40 (2004–2013)2008Engine B5254T3, B5254T7 only
- Volvo S40 (2004–2013)2009–2012Engine B5254T7 only
- Volvo V50 (2004–2013)2006–2007Engine B5254T3 only
- Volvo V50 (2004–2013)2008–2012Engine B5254T7 only
What does this fault code mean?
The measured air quantity sits above the expected value by too wide a margin, while the lambda adaptation is outside its normal range, so the code is set. The usual reasons are leaks, a blockage or a faulty air mass sensor.
Possible causes
- Oxidation and contact resistance in the air mass sensor connector
- Leakage in the intake air path
- A blocked intake system
- Faulty mass air flow sensor
What you can do
- 1Clear the code and road test to see whether it returns
- 2Look at the mass air flow sensor connector for oxidation, play and contact resistance
- 3Check the hoses between the mass air flow sensor and the throttle for leaks
- 4Clean the throttle housing if it is contaminated and see whether the fault clears
- 5If the fault remains, have a workshop check the mass air flow sensor
Symptoms you may notice1
- Malfunction indicator lamp on
What the fault can affect3
- Boost pressure is calculated rather than measured
- Rear oxygen sensor regulation is off
- Misfire diagnosis is disabled
General guidance for car owners. Diagnosis on the car can point to a different cause.