KlaroFault codeP0104
MODERATEMass or Volume Air flow Circuit Intermittent
What this code means
Mass or Volume Air flow Circuit Intermittent.
P0104 is a generic code: it means the same thing on every make. P0104 belongs to family P01xx — Fuel and air metering. Its page explains how to read a code and groups all its codes by part.
Type of fault
The signal drops out or jumps from time to time. This is typical of a poor contact: a loose or corroded connector, or a chafed wire that touches intermittently, often triggered by vibration or heat. The fault may disappear and come back; checking the wiring with the engine running is often revealing.
Mass airflow sensor (airflow meter)
The airflow sensor sits in the intake duct between the air filter and the throttle. A heated wire or film measures how much air enters the engine, and the control unit uses it to calculate how much fuel to inject.
What you notice
Hesitation, lack of power, rough idle, stalling, black smoke on diesels or higher consumption. The control unit may replace the reading with an estimate, so the engine runs, but less well.
How to check it
Check the air filter and the duct for leaks after the sensor: any air that enters unmeasured skews it. Cleaning the sensing element with a dedicated spray fixes some cases. In Klaro, the airflow reading at idle should be steady and increase smoothly with revs; a value that hardly moves or jumps is a clue.
Watch it live in Klaro
With an OBD2 adapter plugged in, these live readings show the part at work, when your car reports them:
- Mass air flow
- Intake manifold pressure
- Short term fuel trim bank 1
- Long term fuel trim bank 1
What to do
Have it checked this week. The car remains usable, but the fault will not clear itself and will fail the roadworthiness test.
Clearing a code switches the light off but repairs nothing: if the fault remains, the code comes back. Clearing a fault code yourself →
How to read this code
- PPowertrain
- 0standardised code
- 1Fuel and air metering
- 04P0104
