Engine
What is a Mass Air Flow (MAF) Sensor?
Measures exactly how much air enters the engine.
Simplified animation — not to scale.
In plain English
A small electronic sensor in the intake pipe, just after the air filter, that uses a heated wire or film to measure the weight and flow of incoming air.
A simple analogy
"It is the engine's breathalyser — it tells the brain exactly how much air it just inhaled so it can pour in the right amount of fuel."
How it works
The ECU uses the MAF reading to calculate the precise amount of fuel to inject so the mixture is perfect. Contamination from oil mist or dirt makes the readings drift, throwing the whole fuelling off.
Signs of trouble
- ⚠Poor fuel economy
- ⚠Hesitation, jerking or lack of power
- ⚠Rough idle or stalling
- ⚠Check engine light with MAF-related codes
Rough UK cost
£80–£330
Parts: £50–£250
Labour: £30–£80
Always get a written quote. Prices vary by car, region, and parts brand.
Heads up: Carautonomy is for general guidance only. If your car is showing warning lights or behaving oddly, get it looked at by a qualified mechanic.