What is a mass air flow sensor?
For most modern automobile engines, the mass air flow sensor is the most important electronic input for the onboard computer to make decisions about air-fuel ratio. The sensor sits in the air induction system, usually right after the air filter. Using a heated wire or a vane meter, the sensor measures the rate and density of the air moving into the engine. This helps the onboard 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 poorly running car — if it runs at all. The car may misfire, idle roughly, surge, or unexpectedly stall. This is due to a poor air-fuel ratio. When the sensor does not read correctly, the computer believes there is either more or less air being ingested than there really is. 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. Typically, when a mass air flow sensor is failing the engine will not stay running, or will run so poorly that the engine or exhaust components are further damaged — especially the catalytic converter. Since postponing service usually results in a higher repair bill, Openbay recommends making an appointment with a quality mechanic who specializes in engine diagnostics as soon as possible. This repair is not overly complicated, so expect the car to be ready on the same day.
What is the typical cost for Mass Air Flow Sensor Replacement?
- Estimated part(s) cost $100–$150
- Estimated labor cost $20–$50
The biggest factor in the repair bill for a mass air flow sensor is the make of the vehicle. Many mass air flow sensors will cost around $100–$150, however some will reach upwards of $400 — especially in higher end German makes. Most of these sensors sit on the air induction system, so installation will not be very expensive, usually around $20–$50. Again, with some German cars, you should expect a higher labor bill, possibly in the $100 range.
Keep in mind, pricing will vary by location and your vehicle make and model. 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