This article was reviewed by Jason Shackelford and by wikiHow staff writer, Eric McClure. Jason Shackelford is the Owner of Stingray Auto Repair, a family owned and operated auto repair shop with locations in Seattle and Redmond, Washington. He has over 24 years of experience in auto repair and services, and every single technician on Jason’s team has more than 10 years of experience.
This article has been fact-checked, ensuring the accuracy of any cited facts and confirming the authority of its sources.
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A combustion engine relies on a delicate mixture of spark, gas, and air to run properly. But how does your engine know if it’s getting enough air or not? That’s the role of the mass air flow sensor (or MAF sensor). You can replace or clean an MAF sensor no problem, but it’s important to reset the sensor when you’re done working on it so that your engine control module (or ECM, basically your engine’s computer) knows to recalibrate the sensor readings. In this article, we’ll show you how!
Things You Should Know
- Reset the MAF sensor by idling your engine without the sensor installed for at least 10 seconds.
- You can also reset the MAF sensor by removing the negative battery terminal and waiting 10 minutes.
- You may be able to drive without the MAF sensor, but it’s bad for your engine to drive without the sensor for too long.
Steps
Resetting the MAF Sensor by Idling
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Remove the MAF sensor with a screwdriver and take it out of the engine bay. With your engine off, locate the sensor in your engine bay (it’s usually between the air filter and the engine manifold). Gently unplug the wires leading into the sensor. Then, grab a screwdriver and remove the fasteners holding the sensor in place to remove it.[1]
- On some newer, modern MAF sensors, you can press a small reset button instead of idling. This is relatively rare though, and you’ll likely need to reset it manually via idling or removing the battery terminal.
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Turn your vehicle on for at least 10 seconds. With the sensor removed, put the key in your ignition and turn the car on. Wait at least 10 seconds for the air to flow through your intake and engine without the sensor attached.[2]
- Your engine’s computer (the engine control module, or ECM) will realize that the sensor is missing and automatically reset its settings. When you reinstall the module, your ECM will realize there’s a module now and take new readings.
- If you want to be 100% positive the ECM gets a clean reading, you can let the vehicle run for 1-2 minutes.
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Shut the engine off and clean or replace the MAF sensor. Pop your hood again and either install the new MAF sensor, or clean the old sensor and reinstall it. Installing a new sensor is easy. Simply plug the wires back into the color-coded ports and screw it in place where you removed the old one.[3]
- To clean the sensor, purchase a mass air flow sensor cleaning spray and follow the instructions on the label. Typically, you just spray the body of the sensor and wait before wiping it clean.
- Install the mass air flow sensor the same way you removed the old one.
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Turn the vehicle back on and reset any computer codes. With the new sensor installed, hop back in the driver’s seat and turn the vehicle back on. Give it a minute to warm up and confirm that your engine isn’t shaking, rattling, or making noise. If you need to reset anything on your computer screen, follow the instructions on the prompts.[4]
- You may have a check engine light pop on depending on your make and model. Either manually reset the check engine light, or complete a drive cycle to clear the error.
Resetting the MAF Sensor by Disconnecting the Battery
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Remove your old MAF sensor with a screwdriver and remove it. Turn your car off and pop the hood. Unplug all of the wires that connect to your MAF sensor and then use a screwdriver to remove the fasteners holding it in place. Take the old sensor out of the engine bay.[5]
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Disconnect the battery’s negative terminal for 10 minutes. Pop the cover on the negative terminal on the battery. Grab a wrench and unscrew the fastener on top of the cable holding it in place. Unscrew the fastener and pull the cable off of the terminal. Press the car horn for a few seconds and then wait at least 10 minutes.[6]
- When you remove the MAF sensor, your vehicle’s engine control module will need to reset. Removing the battery terminal and discharging the battery for 10 minutes will force a full ECM reset.
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Replace or clean your MAF sensor and install it. While you’re waiting the 10 minutes for the battery terminal to finish discharging, you’ve got time to work your magic. Either clean the old sensor if you think it’s still got some life left in it or install your new MAF sensor the same way you removed the old one.[7]
- Use a mass air flow sensor cleaning spray to clean out your MAF sensor before reinstalling it.
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Reconnect the battery, start the car, and clear any error codes. Put the cable back on the terminal and install the fastener on top with your wrench. Then, turn the ignition to start the car and confirm that the engine is running smoothly. If you have any error messages on your computer screen, clear them by following the prompts.[8]
- You may need to reset the check engine light or complete a full drive cycle.
Expert Q&A
Video
Tips
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Don’t want to deal with the headache of replacing or cleaning your MAF sensor? Have a mechanic do it. This is one of the cheaper and easier repairs out there, and it shouldn’t run you more than $120 to $300.[10]Thanks
References
- ↑ https://www.carsdirect.com/car-repair/how-to-tell-if-you-have-a-faulty-mass-airflow-sensor
- ↑ https://carsneedcare.com/how-to-reset-mass-air-flow-sensor/
- ↑ https://www.carsdirect.com/car-repair/how-to-tell-if-you-have-a-faulty-mass-airflow-sensor
- ↑ https://carsneedcare.com/how-to-reset-mass-air-flow-sensor/
- ↑ https://www.carsdirect.com/car-repair/how-to-tell-if-you-have-a-faulty-mass-airflow-sensor
- ↑ https://carsneedcare.com/how-to-reset-mass-air-flow-sensor/
- ↑ https://www.carsdirect.com/car-repair/how-to-tell-if-you-have-a-faulty-mass-airflow-sensor
- ↑ https://carsneedcare.com/how-to-reset-mass-air-flow-sensor/
- ↑ https://autoguysland.com/what-happens-if-you-disconnect-mass-air-flow-sensor/