Symptoms of a Bad or Failing Mass Airflow Sensor

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Cost of Replacing a Bad or Failing Mass Airflow Sensor

Common signs of problems with a mass airflow sensor include running rich at idle or lean under load, decrease in fuel efficiency, and rough idles. Our certified technicians can come to you and diagnose the problem. You will receive a $30 credit towards any follow-up repairs that result from the diagnostic. Following are example prices for Mass Airflow Sensor Replacement. Click on the button below to get an upfront quote for your car.

Cars Estimate Parts Cost Labor Cost Savings Average Dealer Price
2014 Hyundai Sonata $301 $230.94 $70.00 11% $338.44
2008 Nissan Altima $243 $172.86 $70.00 13% $280.36
2004 Saab 9-3 $167 $97.24 $70.00 18% $204.74
2009 Mercedes-Benz E320 $700 $630.08 $70.00 5% $737.58
2006 Mercedes-Benz R500 $309 $238.85 $70.00 10% $346.35
2003 Mercedes-Benz CL55 AMG $309 $238.85 $70.00 10% $346.35
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How to Diagnose a Bad or Failing Mass Airflow Sensor?

mass airflow sensor

Mass Airflow Sensors (MAF) have the responsibility of reporting the amount of air entering the engine to the Powertrain Control Module (PCM). The PCM uses this input to calculate engine load.

There are several designs of MAF sensors, but the most common by far is the hot wire MAF sensor. The hot wire MAF has two sensing wires. One wire is heated and the other is not. The microprocessor (computer) inside the MAF determines the amount of air entering the engine by how much current is required to keep the hot wire about 200 ℉ hotter than the cold wire. Whenever the temperature difference between the two sensing wires changes, the MAF will either increase or decrease the current to the heated wire. This equates to more air into the engine or less air into the engine.

There are a number of driveability issues that arise from faulty MAF sensors.

1. Runs rich at idle or lean under load

These symptoms indicate a MAF that has a contaminated hot wire. The contamination can come in the form of spider webs, potting compound from the MAF sensor itself, dirt that gets attached to oil on the MAF from an over-oiled aftermarket air filter, and more. Anything that acts like insulation to the hot wire will cause this type of issue. The fix is as simple as cleaning the MAF sensor with an approved cleaner, which the technicians at YourMechanic can do for you if they determine that this is the root problem.

2. Constantly runs rich or lean

A MAF sensor that continuously over-reports or under-reports airflow into the engine will cause an engine to run rich or lean. If the engine control system is working correctly, you will probably never notice this except for a change in fuel economy. A trained technician will have to look at fuel trim status with the use of a scan tool to verify this. A MAF sensor that behaves like this will require replacement. Before replacing the sensor, however, the rest of the circuit should be checked for proper operation. If the circuit has an issue, replacing the sensor will not solve your problem.

3. Rough idle or stalls

A completely failed MAF sensor will not send any airflow information to the PCM. This prevents the PCM from accurately controlling fuel, which will result in an engine that either will idle roughly or not at all. Obviously, replacing the MAF sensor is needed in this case.

Sensors
MAF (Mass Air Flow) sensors
fuel economy

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Recent Mass Airflow Sensor Replacement reviews

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YourMechanic Mass Airflow Sensor Replacement Service

Average Rating

4.7/5

Number of Reviews

124

Rating Summary
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Matthew

30 years of experience
268 reviews
Matthew
30 years of experience
Awesome technician. Technician was punctual, very knowledgeable, went above and beyond to ensure the repairs were completed.
2007 CADILLAC ESCALADE EXT - MASS AIRFLOW SENSOR - NEWPORT NEWS, VIRGINIA

Peter

40 years of experience
972 reviews
Peter
40 years of experience
He was on time for our appointment and had it taken care of within the hour. Quality and great communication throughout the process. Thank You Peter!!!
2015 NISSAN QUEST - MASS AIRFLOW SENSOR - ANTHEM, ARIZONA

Joel

18 years of experience
501 reviews
Joel
18 years of experience
I love the convince of using YourMechanic, and I am very pleased with the mechanic, Joel, that YM sent . He is very knowledgeable,,honest,and friendly.
2004 KIA OPTIMA - MASS AIRFLOW SENSOR - ORANGE PARK, FLORIDA

Breck

17 years of experience
314 reviews
Breck
17 years of experience
We always request Breck. He has been taking care of us for a couple of years now and we trust him completely!
2011 NISSAN FRONTIER - MASS AIRFLOW SENSOR REPLACEMENT - HOUSTON, TEXAS

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