How does a MAF sensor work?
The Importance of Air Flow Meters
Installed in the intake pipe between the air filter housing and the intake manifold, most MAF sensors work on the hot wire principle. Put simply, a MAF has two sensing wires. One is heated by an electrical current, the other is not. As air flows across the heated wire, it cools down. When the temperature difference between the two sensing wires changes, the MAF sensor automatically increases or decreases the current to the heated wire to compensate. The current is then changed to a frequency or a voltage that is sent to the ECU and interpreted as air flow. The quantity of air entering the engine is adjusted accordingly.
When a MAF sensor fails, the engine will not know the right amount of fuel to add, causing several common signs:
- Check engine light
- Engine runs rich at idle or lean under load
- Engine runs rich or lean: caused by the MAF
- Rough idle or stalls
- Excessive vibrations when stationary
- RPMs changing noticeably without driver input
How to install mass air flow sensor
|
|
|
|
|
|---|---|---|---|
Step1When replacing a mass air flow sensor, first locate the sensor which is positioned in the air intake tube between the air filter housing and throttle body |
Step2Release the safety clip and gently pull the connector from the sensor |
Step3A clamp is used to attach the sensor to the air intake tube, use a screwdriver or small socket and loosen the clamp |
Step4Next, undo the inlet clip on both sides. There are many methods of holding the MAF in place, the principle is the same |
|
|
|
|
|
|---|---|---|---|
Step5Once all mounting clips or bolts have been undone, lift the sensor and remove it from the engine bay |
Step6After the sensor has been removed, inspect internal parts and electrical connector for damage |
Step7Compare the old sensor to the replacement unit, they should match identically, remove dust caps before installation |
Step8Gently reinstall the sensor into the inlet and outlet tubes, ensuring a proper seal between the sensor and the tube |
|
|
|
|
|
|---|---|---|---|
Step9After connecting the sensor to both inlet and outlet tubes, tighten the clamp and attach the clips |
Step10Reattach the sensor electrical connector ensuring a small click, when completely connected |
Step11Once the sensor has been replaced, attach a code reader to the ALDL connector |
Step12Turn the ignition key to the "ON" position and follow the prompts to clear any codes in the system |
