How to Replace a Mass Air Flow Sensor

Easy step by step guide on how to replace an automotive mass air flow sensor P0100, P0101, P0102, P0103 and P0104, though appearances may vary, the process is similar for most vehicles.

Difficulty Scale: 3 of 10

Begin with the vehicle on level ground, parking brake on, engine off.

Step 1 - When 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.

Mass Air Flow Sensor
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Step 2 - Release the safety clip and gently pull the connector from the sensor.

Remove Electrical Connector
Step 3 - A clamp is used to attach the sensor to the air intake tube, use a screwdriver or small socket and loosen the clamp.

Loosen or Remove Clamp
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Step 4 - Next, undo the inlet clip on both sides. There are many methods of holding the MAF in place, the principle is the same.

Undo Mounting Clips
Step 5 - Once all mounting clips or bolts have been undone, lift the sensor and remove it from the engine bay.

Remove Mass Air Flow Sensor
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Step 6 - After the sensor has been removed, inspect internal parts and electrical connector for damage.

Mass Air Flow Removed
Step 7 - Then, compare the old sensor to the replacement unit, they should match identically. (Note: remove dust caps before installation.)

New Mass Air Flow Sensor
Step 8 - Gently reinstall the sensor into the inlet and outlet tubes, ensuring a proper seal between the sensor and the tube.

Reinstalling Mass Air Flow Sensor
Step 9 - After connecting the sensor to both inlet and outlet tubes, tighten the clamp and attach the clips.

Reinstall Clamp and Tighten
Step 10 - Then, reattach the sensor electrical connector ensuring a small click, when completely connected.

Reinstall Electrical Connector
Step 11 - Once the sensor has been replaced, attach a code reader to the ALDL connector.

Attach Code Reader
Step 12 - Turn the ignition key to the "ON" position and follow the prompts to clear any codes in the system.

Clear Codes
Helpful Information

After starting the engine post sensor replacement, the sensor instantly calibrates itself so there is no learn time required. This sensor is subject to debris and contamination which can be avoided by cleaning the sensor (Note: Some sensors are located inside the air filter housing, not all cars are equipped with a mass air flow sensor, consult a repair manual for exact component location.)

Best Practices

  • Clean the air intake tube and connection points to ensure proper installation.
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