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

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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.

A: Here is a breakdown of the wiring color cod...

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

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