Mechanics

Mass Air Flow Sensor MAF Replacement

How to Replace a Mass Air Flow Sensor MAF

The mass air flow sensor or MAF is a vital part to your cars computer system. This device is used to measure the amount of air being processed through the engine at any given second. There are two styles of mass air flow sensors. The more popular type is designed with a "hot wire" that when air travels across it the ohms reading changes. The system computer PCM powertrain control module uses this feedback information and adjusts the fuel and ignition systems accordingly. The other style of mass air flow sensor uses a mechanical door that blocks the air passage when the motor is not running and then opens when the motor is running.

The faster the engine is running the more the door opens. This mechanical style of mass air flow sensor is designed with a rheostat which is connected to the computer. Never the less, both of these mass air flow sensors can wear out or become contaminated. In most cases changing a mass air flow sensor is a relatively an easy job and should only take about twenty minutes. (Note: not all cars are equipped with a mass air flow sensor, consult a repair manual if you are unsure of your cars sensor location).

Before we begin park your car on level ground in park with the emergency brake set. Please wear safety glasses with gloves and protective clothing.


Supplies and Tools Needed to Complete this Job

1. Replacement Mass Air Flow Sensor

2. Screw Driver Set

3. Socket and Ratchet Set

4. Shop Towels

5. Solvent such as Carburetor Cleaner
 

Instructions

Step 1 - Release both the primary and secondary hood latch releases. Raise the car's hood and support it with a prop rod if needed.

Step 2 - Locate the mass air flow sensor in the intake tube or near the air filter housing.

Step 3 - Remove the mounting hose clamps or rings holding the air tube to the sensor, then remove the tube.

Step 4 - Disconnect the electrical connector from the mass air flow sensor

Step 5 - Remove the three or four mounting bolts holding the sensor to the body plate. (Some Ford mass air flow sensors are located inside the air filter housing).

Step 6 - Loosen and remove the mounting screws holding the sensor to the case, if any.

Step 7 - Match up the new mass air flow sensor to the old unit, particularly the electrical connector.

Step 8 - Install the new mass air flow sensor and reassemble.

Note: When the engine first starts with a new mass air flow sensor it might not run correctly, allow time for the system to recalibrate, about five minutes of engine run time.


Best Practices

  • Always clean the air intake tube and connection points to ensure proper installation.
     
If further assistance is needed, our certified car repair technicians are ready to answer your car questions. Also, gain manufacturer specific instructions and information by clicking - Auto Repair Manual


Related Car Repair Information

AUTHOR


Written by
Co-Founder and CEO of 2CarPros.com
35 years in the automotive repair field, ASE Master Technician, Advanced Electrical and Mechanical Theory.


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Article first published (Updated 2013-08-16)