Mass Air Flow Sensor (MAF)

What is a Mass Air Flow Sensor (MAF)?

The Mass Air Flow Sensor (MAF) measures the levels of air entering the engine through the intake system. The readings from the sensor are passed to the ECU (Engine Control Unit aka the car's brain!). The ECU will use this information so that it can calibrate the amount of fuel that it needs to inject via the fuel injectors.

The fuel/air levels are constantly tweaked by the ECU based on the input from the MAF sensor. If for some reason the MAF sensor is not sending the correct readings then the engine will behave erratically as it will be operating with an incorrect fuel / air mix.

MAF sensors are prone to error when they get dirty. As a car ages there can be a build up on the sensor which can degrade its performance and affect the data it sends to the ECU. The sensor can be cleaned (quite often as a DIY job) to improve accuracy but sometimes they also fail and need replacing.

What problems can be caused by a faulty Mass Air Flow Sensor (MAF)?

Engine doesn't start up and/or cuts out when running

Engine is misfiring

Engine does not sound or feel normal

Check Engine warning light showing on dashboard

Engine is running rough

Fuel consumption seems above normal range

How much does it cost to replace the Mass Air Flow Sensor (MAF)?

MAFs can cost anywhere from £100 to £500 for the sensor unit. Whilst they can be expensive they're generally easy to fit and will need an hour or less of labour to do so.

193 problems that mention the Mass Air Flow Sensor (MAF)

Showing the latest 10, see more problems here

2
responses

Flat spot for a few seconds when starting off

Flat spot lack of acceleration on tack off

2006 Vauxhall Corsa sxi cdti
Posted: Oct 3, 2021

2
responses

Engine bay sound

Have an unsettling sound like wind through a pipe on accelerating and decelerating. (sputters a bit when decelerating). Sound not there when idling and when the clutch is pressed down/disengaged. Can...

2010 Vauxhall Insignia 1.8 petrol
Posted: Sep 26, 2021

3
responses

Intermittent cutting out at junctions / traffic lights

Normally once engine warm I come to a stop engine cuts out and battery light illuminates on dashboard, will start again with no issues

2010 Seat Leon 1.6 cr tdi Dsg
Posted: Sep 23, 2021

4
responses

Power loss

Hi, Latter part of last year noticed when pulling away loss of power from 1000 to 1500 rpm on reaching 2000 rpm she was off like a shot. On taking the MOT it failed on binding handbrake osr so thought...

2007 Vauxhall Antara 2ltr CDTI SE
Posted: Sep 20, 2021

2
responses

Jerky missfire, engine cuts out.

When the engine is warm and doing around 2000 - 2500 rpm in 2 or 3rd gear the engine "misses". No backfire it just seems that the engine stops for a brief second causing terrible kangarooing type moti...

2010 Kia ProCeed 1.4 crdi 3 door
Posted: Aug 24, 2021

1
response

Stuttering at slow speeds

Stuttering when accelerating in the lower gears

2017 Vauxhall Meriva 1.4
Posted: Aug 18, 2021

3
responses

Chugging when driving

The car seemed to cough a couple of times now it's chugging in every gear when driving and loss of power engine management light is on

2008 Vauxhall Astra 1.8 sri
Posted: Aug 12, 2021