Code E034: Mass Airflow Sensor Circuit: Notes

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.