P0103 — Mass or Volume Air Flow Circuit High Input

What it means

The MAF signal has stayed above the allowed maximum, so the control module calculates more incoming air than the engine actually gets and injects too much fuel. Typical symptoms are black smoke, a strong fuel smell, rough idle and high consumption. Long term this loads the catalytic converter and can foul the spark plugs.

Likely causes (most common first)

1. Faulty mass air flow sensor with drifted or shorted signal
2. Short to voltage in the sensor signal wire or a chafed harness
3. Water or moisture in the sensor connector
4. Incorrect or non-matching replacement sensor fitted
5. Intake system modification changing air velocity at the sensor
6. Faulty engine control module (rare)

Can you drive with it?

Short distances are possible, but the over-rich mixture damages the catalytic converter, so do not postpone the repair.