DTC 34

Fig. 012 - Wiring Diagram for Code 34 MAF Sensor (Signal Frequency Low). VIN S, VIN W:

CODE 34

MAF SENSOR (SIGNAL FREQUENCY LOW)

2.8L "X" SERIES

FUEL INJECTION (PORT)

The MAF Sensor measures the flow of air entering the engine. The sensor produces a frequency output between 32 and 150 hertz. A large quantity (high frequency) indicates acceleration, and a small quantity (low frequency) indicates deceleration or idle. This information is used by the ECM for fuel control.
Code 34 will set if:
a. Engine running
b. MAF sensor disconnected, faulty relay or MAF signal circuit shorted to ground.
OR
c. Air Flow less than 2 grams per second (low frequency).

Fig. 011 - Chart - Code 34 Mass Air Flow Sensor Circuit:

1. A loose or damaged air duct can set code 34.
2. Checks to see if ECM recognizes a problem. A light off at this point indicates an intermittent problem.
3. Checks to see if 5 volt reference signal from ECM is at MAF sensor harness connector. Less than 1 volt indicates a faulty CKT 492, wiring connector, or ECM.
4. Checks continuity of electrical circuit at MAF sensor.
5. Checks for open in 12 volt supply