VOLVO
ECM-136F - Mass air flow (MAF) sensor. Signal too low
System
Engine Control Module (ECM)
Volvo models this fault code applies to
Applies to the following models:
3 modelsC30 (2007–2013), S40 (2004–2013), V50 (2004–2013)
What does this fault code mean?
The ECM continuously checks that the MAF sensor signal is plausible. The fault is set when the signal reads low and departs from the sensor's expected characteristic. An air leak in the intake, contact problems or breaks in the wiring can be behind it.
Possible causes
- Air leak in the intake system
- Play, contact resistance or oxidation in the connections
- Signal wire shorted to ground
- Open circuit in the signal wire
- Open circuit in the voltage supply
- Damaged MAF sensor
What you can do
- 1Read the fault code, clear it and test drive to see whether it returns
- 2Check that the intake system does not leak air, for example in hoses and connections between the MAF sensor and the engine
- 3Check the MAF sensor connector for play, contact resistance and oxidation
- 4With a multimeter, check that the signal wire is not shorted to ground and has no break
- 5If you have a diagnostic tool: read air mass in live data with the engine running and check that it rises when the accelerator pedal is pressed
- 6If no leak or connector fault is found: have a workshop check the MAF sensor
Symptoms you may notice3
- Reduced performance
- The engine feels jerky at steady speed
- The check engine lamp behaves abnormally or lights up
What the fault can affect1
- The engine control uses a calculated air mass
General guidance for car owners. Diagnosis on the car can point to a different cause.