Skip the auto shop - Our mechanics make house calls

Q: What value should the MAF signal be at idle?

asked by on

I'm testing the mass air flow sensor, what is the known good spec for the signal to the ECU at idle?

My car has 212000 miles.
My car has an automatic transmission.

Here is a breakdown of the wiring color codes, and the associated voltages on each, for engine running and ignition on. The signal from the mass airflow sensor should steadily sweep from 1.9 to 5 volts as you press and release the gas pedal.

TERMINAL

B/Y (Power supply) G/O (Burn-off) G/B (Air flow mass) G/Y (Ground) B/O (Ground)

IGNITION ON

B/Y - Approx. 12V G/O - 0V G/B - 1.0 - 2.0V G/Y - Approx. 0V B/O - Approx. 0V

ENGINE RUNNING

B/Y - Approx. 12V G/O - 0V G/B - 1.9 - 5.0V G/Y - Approx. 0V B/O - Approx. 0V

Was this answer helpful?

Need advice from certified mechanic? Get help now!

Over 1000 mechanics are ready to answer your question.
The statements expressed above are only for informational purposes and should be independently verified. Please see our terms of service for more details

Get an instant quote for your car

Our certified mechanics come to you ・Backed by 12-month, 12,000-mile guarantee・Fair and transparent pricing

Get a quote

What others are asking

Q: Rough idle with DTC P0171, engine stalls unless MAF sensor is unplugged - 2007 Volvo S40 2.4i

Your mass air sensor has most likely gone bad and/or is not giving correct data to the computer. Replace the sensor, clear the codes, and retest this.

Q: Car deck

Hi, thank you for writing in. I am assuming you are talking about the radio. When installing a new radio, it really depends on what brand/type of radio you will putting in. A lot of manufacturers will have a plug...

Q: Why does my car shut off after driving it for a while?it wont start back up until it cools down even though its not overheating

This may be a sign of a faulty ignition coil. Ignition coils are coated with a varnish-like insulation that becomes brittle over time after being stretched then contracted repeatedly. The insulation develops small fractures that open when heated and close...

Related articles

How Do Power Car Windows Increase Passenger Safety?
Power windows are responsible for approximately 2,000 emergency room visits every year. When a power window closes, it exerts enough force to bruise or break bones, crush fingers, or restrict an airway. Though...
How Long Does a Heater Control Valve Last?
Keeping the right amount of coolant in a car is essential in keeping the engine at the right temperature. Failing to have the right amount of coolant or even bad elements...
Rules of the Road For Iowa Drivers
Driving on the roads requires knowledge of the rules, many of which are based on common sense and courtesy. However, even though you know the rules in...