P0103Mass or Volume Air Flow Sensor A Circuit High
- Generic OBD-II code · Powertrain
- Turns on the check-engine light
- Matters for the ITP
- Can trigger limp mode
- Needs a drive cycle to confirm a fix
- How the car detects it
- The mass air flow sensor (MAF) sits between the air filter and the throttle or compressor and measures how much air the engine draws in; fuel quantity, load and ignition are calculated from it. Most are hot-film or hot-wire sensors that output either a voltage or, on GM, Saab and newer Ford systems, a frequency. P0103 means the signal is above its electrical upper limit. Documented limits: GM petrol 14,500 Hz or more, GM diesel above 12,500 Hz, Saab 9-4X above about 15,150 Hz, Ford analogue above 4.785 V (checked only below 4,000 rpm so that high load is not mistaken for a fault). Typical causes are a signal wire shorted to a voltage source, failed sensor electronics or interference from a harness routed too close to ignition coils, relays or motors. GM and Saab need two trips; the engine switches to a calculated air mass.
- What you may notice
- Check engine light on
- Substitute value mode, lack of power
- Rich mixture possible (smoke, consumption)
- Rough idle, hesitation
- Likely causes
- LikelySignal wire shorted to voltage or to the supply wire
- LikelySensor electronics failed
- PossibleInterference from harness routed near ignition coils, relays or motors
- RareWater in the connector or on the element
- Inspection (ITP)
- Matters for the ITP. While the check-engine light is on, the car fails the emissions check.
- Repair
- Easy · Often possible to do yourself.Typical cost: €20 – €300
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.