OBD-II · Engine and powertrain (P)
P0103
Mass air flow circuit high input
What it means
The MAF signal voltage or frequency is above the circuit threshold, rather than simply indicating high engine air flow.
Symptoms
- hesitation or flat spots when accelerating
- reduced power, sometimes limp mode
- rough idle or stalling
- black smoke on diesels
- engine warning light
Likely causes, most likely first
| No. | Cause |
|---|---|
| 01 | signal short to voltage |
| 02 | failed MAF sensor electronics |
| 03 | poor sensor ground |
| 04 | chafed wiring or damaged connector |
| 05 | incorrect electrical sensor specification |
What to check, step by step
- 01Inspect the MAF connector and wiring for damage, corrosion or a loose plug
- 02Check the sensor supply and ground with a meter
- 03Read the MAF value in live data: with the key on and engine off it should be near zero, and it should rise smoothly with rpm
- 04Unplug the MAF with the engine idling: if the engine runs better unplugged, the sensor is suspect
- 05Replace the sensor with an OE-quality part if the wiring is good (cheap copies often read wrong)