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MAF sensor replacement in my Audi A3

For a short while now, my Audi A3 has issues with fuel consumption, sluggish response, low performance, jerky driving and black smoke out the exhaust on the car. That on top of my existing Turbo problems is a frustrating combination.

Driving home I received a fault code light on my car, scanning with VCDS received an Intermittent error with the MAF sensor readings.

Whilst not a true diagnostic, I figured it might just be easier purchasing a replacement MAF sensor on my car and fitting it to rule it out. So I purchased a replacement MAF sensor from Darkside Developments, and received it within a couple of days through Royal Mail. Fitting to my car took less than 30 mins. This isn’t a full guide, as it was something I did on my lunch at work, just something to give people pointers.

Fitting the Mass Air Flow sensor to my Audi A3

Not sure if this is the actual text book procedure, so feel free to adjust for yourself and do the steps what work for you. This is intended to help others with changing their Mass Air Flow sensor in their Audi A3 if they don’t have a step by step guide on what to do.

Tools for changing the Mass Air Flow Sensor in Audi A3
Not many tools needed

In order to change the Mass Air flow sensor the way I did it you need nothing more than 3 tools

  • Screwdriver (mine is an interchangeable bit, Phillips and Flat)
  • Pliers (for the spring clamps)
  • 10mm Spanner (for the battery connectors)
Battery removal to clear memory
Disconnect battery terminals
  • Using a 10mm Spanner, undo the negative and positive battery terminals on the car, then remove the battery
Battery removed Audi A3
Battery terminals exposed
  • In order to clear any learned settings in the ECU, and discharge any remaining current, I touched the terminals together to short them out. The only reason I did this step, was as noted, I read somewhere that it’s recommended because the ECU learns and stores the values it reads. So my disconnecting the battery, it forces the car to relearn them. No idea if it works.
Undoing the air intake spring hose clamp
Undo the spring hose clamp
  • Loosen the spring hose clamp and slide it to the right to allow you to undo the MAF from the pipe. Loosen it by squeezing the metal tabs together to expand it
MAF sensor connection on Audi A3
Terminal disconnection
  • I’ll admit, these thing are buggers. The first time I disconnected it, came off easy, tried this time it was awkward. Normally pushing in the connector and lifting it should remove it. Go slow, the release tab locks inwards at the bottom. I’ll double check this, but I believe the removal should be push down and pry outwards slyly to remove it. If you know the correct method, feel free to comment and I’ll update this post. Plenty of these get snapped due to incorrect removal.
  • EDIT – To release the tab, press the top portion in whilst pulling upwards
Screws for Air Filter housing Audi A3
The screws to undo and remove the air filter housing
  • Undo the screw on the air filter housing, pictured with the yellow arrows.
  • After you have disconnected the electrical connector, intake housing, intake pipe, and the vacuum pipe (pictured between the upper most yellow arrows). You should be able to simply lift off the housing and remove it
  • If you look at the Mass Air Flow sensor on the Audi A3 once removed, you will find two screws. You need to undo these aswell
Old MAF sensor removed
The old mass air flow sensor removed
  • After you have undone the two screws on the Audi A3, the old mass air flow sensor will pull out. It’s held in with a large rubber O-ring so it will be quite stiff
Replacement MAF sensor in protective packaging
Replacement MAF sensor
  • This was the replacement Mass Air Flow sensor that I received for the car. It’s security sealed, so once opened it can’t be returned. I recommend comparing it side by side with your old one before you open this, so that in the very least you’re making sure you have the right one for the car.

MAF sensor covers

Protective covers on new sensor

  • When you receive the new Mass Air Flow sensor, it will have protective covers that you will need to remove to stop dirt ingress that can damage the sensor. I recommend removing one side at a time, and only do it just before you insert it to minimise exposure to the air.
  • Simply reinsert the way the old one was fitted (important, make note of the directional arrow which should point towards the car) when refitting.
  • Insert the screws and tighten it up, then reassemble all the components back on the car
Mileage of maf sensor changed SO57RMX
Mileage when the MAF sensor was replaced
  • This is nothing more than a note of when I replaced my Mass Air Flow sensor on my Audi A3. If it had failed, this was the mileage

Steps after fitting a new Mass Air Flow sensor to the Audi A3

If you’ve done the same stpes I’ve done above, you normally need to do the following

  • Start the car, and let it idle for 5 mins. It will probably run rough and then smooth out
  • Recalibrate the steering system (Traction light and Yellow Steering Wheel light). You do this with the following procedure
    • Turn the wheel full lock left
    • Turn the wheel full lock right
    • Centre the steering wheel
    • Drive approx 50-100 yards, the lights should then go out

Did the Mass Air Flow sensor replacement work?

Unsure. My car has had multiple problems with the Turbocharger, and I think there’s been a knock on effect with my car systems. I’m still receiving a communication message related to the readings. So I may possibly have a wiring fault somewhere with the connector. I also believe I’ve got other problems which could potentially cause the same message like an Air Intake leak, or a blocked EGR manifold. All these will be reviewed at when I replace my Turbocharger to make sure they’re covered. At the very least, I have kept my old Mass Air Flow sensor as a spare, and also had a replacement MAF fitted to the car (which cost me £116) that rules this out from future problems.