P0103

Note: The MAF sensor is a combined MAF sensor and IAT sensor.

DTC P0103
Mass air flow sensor fault Drive cycle A:Signal out of range - above maximum.

Possible causes by suggested order of priority:
- MAFS contaminated.
- Open circuit - C636/23 (UG) to C149/5 (UG).
- Open circuit - C636/9 (RB) to C149/3 (RB).
- 5V MAFS supply voltage C149/4 (R) to C149/3 (RB).
- 12V MAFS supply voltage C149/2 (NK) to C149/3 (RB).
- Connectors C149, ECM C636 (B).
- Fuse F2 Engine Compartment Fusebox.
- MAFS faulty.

MAFS contaminated.
- Visually inspect the metal and plastic mesh on the upstream side of the airflow meter.
- If this mesh is contaminated then this is a good indication that the sensor film is also contaminated.
- MAFS Fault - Contaminated hot film sensor.

Open circuit - C636/23 (UG) to C149/5 (UG).
- Check resistance > 1M Ohm

Open circuit - C636/9 (RB) to C149/3 (RB).
- Check resistance > 1M Ohm

5V MAFS supply voltage C149/4 (R) to C149/3 (RB).
- 5V MAFS supply voltage C149/4 (R) to C149/3 (RB).
Between 4.5V and 5.5V.
- If the voltage is too high a short circuit to battery or faulty ECM should be suspected.
- If the voltage is too low an open circuit or connector problem should be suspected.

12V MAFS supply voltage C149/2 (NK) to C149/3 (RB).
- 12V MAFS supply voltage C149/2 (NK) to C149/3 (RB)..
Between 11.5V and 15.0V.
- If the voltage is not present check F2 Engine Compartment Fusebox and open circuit C149/2 (NK) to C570/5 (NK).

Connectors C149, ECM C636 (B).
- Check for connector not correctly latched, backed out pins, damaged pins, corroded pins

Fuse F2 Engine Compartment Fusebox.
- Check for fuse not correctly inserted, fuse blown, fuse connections loose, damaged or corroded.
- Certain diagnostics may also perform further checks to try and narrow down the fault. Eg Check if other circuits fed by the same fuse are also experiencing problems

MAFS faulty.
- Check MAFS by substituting with known good unit.
- MAFS Fault.