While there are speed density systems (like Chryslers and Jeeps in the 90s and early 2000s) that don’t use a MAF sensor, the mass air flow (MAF) sensor is one of the most important parts of the fuel management systems that use this type of sensor.
Most MAF sensors either have a “hot wire” or a “hot film” that is maintained at a certain temperature by the electronic circuit in the sensor. As incoming air attempts to cool the sensor, the electronics instantly increase current flow through the sensing element to maintain the programmed temperature, and the amount of current required to maintain the temperature of that hot wire or film is converted to a number the ECM can use to determine how many grams of air per second are passing through the sensor, which also measures the temperature of the incoming air.
When the film or the hot wire are coated with anything that prevents the air from directly affecting the sensor’s ability to tell the ECM the truth about airflow, the fuel management system won’t be able to maintain the proper air-fuel ratio. If you aren’t experiencing any driveability issues (sluggish performance, fuel management related trouble codes, etc.), the sensor probably doesn’t need cleaning anyway.
Cleaning your mass air flow sensor is actually a pretty simple task that you can do by yourself. Here are a few tips that can make the entire process easier:
To begin with, use a bright light or take a high resolution picture of the sensing elements (if you can) with your cell phone so you can zoom in and see if the sensor even needs cleaning. If you’ve been using a good air filter and usually drive in town, it probably won’t need cleaning, anyway.
You’ll save yourself a lot of time and effort later on by preparing everything you need before you begin. Depending on how the sensor is attached, you’ll need a Torx or a hex socket and ratchet to remove it. Prepare a screwdriver, old or disposable towels, and a mass air flow sensor cleaner.
Pro Tip: Some MAF sensors are bolted to their housings with “tamper proof” Torx bits. The head of one of the Torx bits will be filled with sealer to discourage removing the sensor.
Before you can clean your mass air flow sensor, don’t forget to let the engine cool down first. Turn your engine off, and wait for about 10 minutes until the engine is nice and cool.
This is a good practice even though the air cleaner and MAF sensor housing isn’t likely to burn you even if the engine is still hot. The MAF sensor cools off very rapidly too.
Protect yourself by wearing the proper safety gear. Wear safety glasses and thick work gloves to protect your eyes and skin from oil, fumes, and other debris while working. MAF sensor cleaners are also highly flammable, so be sure to work in a well-ventilated area away from open flames.
Caution: Chemicals like MAF sensor cleaner, brake parts cleaner, carburetor cleaner, etc. can go through your skin if you aren’t wearing gloves. Always wear proper protective equipment.
The MAF sensor’s exact location can vary depending on your vehicle’s year, make, and model, but it is usually located between the air filter and throttle body or, in some cases, it may even be bolted directly to the throttle body itself. If you aren’t sure where it is, consult your owner’s manual or ask a mechanic for help.
To remove the MAF sensor, you’ll have to unplug it from your vehicle’s electrical system first. Gently unplug the connector, which usually has a head that you have to squeeze, to remove it from the sensor.
Some connectors have a plastic lock that is a different color from the rest of the connector and it will need to be moved to a different position before the connector catch can be released.
Once the MAF sensor is unplugged, you can now remove it from your vehicle. Use a screwdriver or other suitable tool (a Torx bit, for example) to loosen the screws and brackets holding it in place.
Lay an old towel on your workbench and place the MAF sensor on it for cleaning. That way, you’re less likely to damage the sensor or stain the table.
Don’t do this in the kitchen for obvious reasons. Besides, you won’t be holding the sensor in your bare hand if you chose not to wear gloves. Further, the towel will mitigate splattering when the aerosol is applied.
Before you apply the cleaner to the sensor, be sure to read the instructions on the packaging. You usually have to spray it on the sensor around 10 to 15 times. Don’t forget to clean the sides, housing, connectors, and terminals too.
Be careful not to get any cleaner on the hot wires or plate if your vehicle has a hot wire MAF sensor.
MAF cleaners usually dry pretty quickly, so you don’t have to wait too long for the sensor to dry. Follow the wait time indicated in the cleaner’s instructions.
Don’t try to wipe it with a dry cloth, or you might end up damaging its parts. Just let it air-dry for a few minutes.
Once the MAF sensor is completely dry, all that’s left to do is to reinstall it in your vehicle. Screw the MAF sensor back into the brackets, and then reattach its connector. After a few minutes, you can go ahead and start your engine. It should run smoothly with the check engine light turned off.
While others might recommend using isopropyl or rubbing alcohol, we strongly advise against it. MAF sensors have delicate wires or plates, which means you can easily damage them by using the wrong cleaner. Other types of cleaners like brake cleaners can leave unwanted residue and damage the sensor. Safely clean your MAF sensor by only using cleaners specifically formulated for MAF sensors.
It’s a good idea to make cleaning the MAF sensor part of your routine maintenance. However, if you maintain your air filter replacement intervals, it’s usually not needed.
Every time you change the air filter, you can go ahead and give the MAF sensor a quick clean. If your scan tool picks up on a diagnostic trouble code related to the MAF, it’s also a good idea to clean the sensor.
Aside from an illuminated check engine light, a dirty MAF sensor can prevent your vehicle from accelerating properly, which can be dangerous when you’re driving on highways.
Rough idling, engine hesitation, and surging are also common. You’re also likely to notice black smoke flowing out of your tailpipes. Unless you want to deal with all that, you should clean your MAF sensor every now and then.
It depends. Mass air flow sensors can cost anywhere from $10 to $1000, but the final price can vary depending on your vehicle’s year, make, and model. This doesn’t include labor costs, which can range from $50 to $220 per hour. Avoid all these fees by regularly cleaning your MAF sensor.
Any information provided on this Website is for informational purposes only and is not intended to replace consultation with a professional mechanic. The accuracy and timeliness of the information may change from the time of publication.