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.

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

Showing the latest 10, see more problems here

1
response

My 2004 touran struggles to start under hot temperatures and idles rough, however on a cold start it fires up nicely and runs how it should

My 2004 touran struggles to start under warm temperatures and idles rough, however on a cold start it fires up nicely and runs how it should the idle is also lumpy and I can also hear a faint thumping...

2004 Volkswagen Touran 1.9 tdi pd105
Posted: Jun 29, 2022

1
response

Engine light came on and mercedes c180 manual transmission became more"heavy" on road, needs more acceleration and fuel consumption increased badly

Electrician says knock sensor have to be replaced. When diagnosed it listed two problems. Mass air flow sensor and knock sensor had electrical fault. Mass air flow sensor was very dirty and had to be ...

2010 Mercedes Benz C Class 1.6l
Posted: Jun 28, 2022

1
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Car tends to cut off when warm

Car drives perfectly fine but if there’s a load on the battery tends to cut off, starts up ok ish but everytime the fan kicks in or even if I put the wipers or just the headlights it stalls. Only ha...

2009 Ford KA 1.2
Posted: Jun 13, 2022

1
response

Engine cuts out when hot.

I have a hyundai getz 2006. Engine runs ok but as soon as it gets hot the engine misfires and dies. Starts fine again but dies when it gets hot again. Does not seem like the engine fan comes on.

2005 Hyundai Getz 1.6
Posted: Jun 6, 2022

1
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Very slow getting up speed

Very little power in first and second gear

2010 Renault Clio Eco2
Posted: Jun 1, 2022

3
responses

Engine

starts and runs well until you to a slight bank or traffic lights it starts to cut out

2004 Nissan X-Trail x trail
Posted: May 28, 2022

1
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Automatic kangoo Engine stalling when starting and losing power when driven

Automatic car. Stalls when starting and loses power when driven

2006 Renault Kangoo 1.6
Posted: May 14, 2022

1
response

Engine shakes

Engine shakes on tick over

2006 Vauxhall Agila 1.0
Posted: May 9, 2022

1
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Cutting out

Have had the throttle replaced and a service, it is greatly improved but finding when it gets really warmed up it will cut out at a junction , no lights come on and is running well .

2009 Skoda Fabia Fabia mark 2
Posted: May 4, 2022

1
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Chugging

My car is jumping like a kangaroo. First it was only doing it in second gear, but now, second and third. Only does it after car been parked up few hours.

2008 Vauxhall Vectra 1.8
Posted: May 3, 2022

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