Code E034: Mass Airflow Sensor Circuit: Notes

WARNING: This page is about a different car, the 1990 Buick Riviera and 1990 Buick Reatta. However, it is still accessible from the selected car via links, so may be relevant.

The Mass Airflow (MAF) sensor measures the flow of air which passes through it in a given time. The ECM uses this information to monitor operating condition of engine for fuel delivery calculations. A large quantity of air movement indicates acceleration, while a small quantity indicates deceleration or idle.

The MAF sensor produces a frequency signal, which cannot be easily measured. The sensor can be diagnosed using procedures in this chart. Code E034 will set, when either of the following sets of conditions exists:

Engine running.
No MAF sensor signal for 250 milliseconds.
Above conditions present for more than 4 seconds.

NOTE: Test numbers refer to test numbers on diagnostic chart.

Test Number 1) This step checks to see if ECM recognizes a problem.

Test Number 2) A voltage reading at sensor harness connector terminal "A" of less than 4 volts, or greater than 6 volts, indicates a fault in circuit No. 492 or poor connection.

Test Number 3) Verifies that both ignition voltage and a good ground circuit are available.