Mass Air Flow Sensor Replacement

What is a mass air flow sensor?

For most of the modern engines on the road, the mass air flow sensor is the most important electronic input for the onboard computer to make decisions on air-fuel ration. The sensor sits in the air induction system usually right after the air filter. Using a heated wire or possibly a vane meter the sensor measures the rate and density of the air moving into the engine. This helps the on board computer to shorten or lengthen the fuel injector open time to meet the ideal ratio of 14.7 parts air to 1 part fuel.

What are the symptoms of a faulty mass air flow sensor?

A really crappy running car, if it runs at all. The car may misfire, idle poorly, surge, and unexpectedly stall. This is due to the poor air-fuel ratio. When the sensor does not read correctly, either the computer believes there is more or less air ingested by the car than in reality. The oxygen sensor in the exhaust stream can send information to the computer to help correct the imbalance, but these adjustments will only go so far.

How severe is a faulty mass air flow sensor?

Critical. Most of the time if our mass air flow sensor is failing, the engine will not stay running or run so poorly that the engine is further damaged, especially the catalytic converter . Best to find a good mechanic one who specializes in engine diagnostics and set an appointment for as soon as possible. Postponing will only result in a higher repair bill This repair is not overly complicated, so expect the car to be ready same day.

What is the typical cost to replace a mass air flow sensor?

  • Estimated part(s) cost = $100 - $150
  • Estimated labor cost= $20 - $50
  • Estimated total cost = $120 - $200

The biggest factor in the repair bill for a mass air flow sensor is the make of the car. Many mass air flow sensors will cost around $100 to $150, however some will reach upwards of $400, especially in nicer German makes. Most of these sensors sit on the air induction system, so installation will not run very high, usually $20 to $50. Again some German cars will be the exception, so expect a higher labor bill, somewhere in the $100 range.

Keep in mind, pricing will vary by location and your vehicle make and model. If you're not already, save time by using Openbay to compare pricing and book an appointment with a qualified repair shop in your area.

Service article written by an ASE Master Technician