Air Flow Meter/Sensor: Testing and Inspection

DTC 23 - MASS AIR FLOW SENSOR





Diagnosis
- The Mass Air Flow Sensor signal is abnormal.
- The harness connector between Engine Control Module (ECM) and Mass Air Flow Sensor is in short or open.

Trouble Symptom
- Erroneous idling.
- Engine stalls.
- Poor driving performance

1. Check input signal for ECM.
a. Turn Ignition Switch to "ON".





b. Measure voltage between ECM and body.

Connector & Terminal / Specified Voltage:
(E3O) No. 5 - Body / 0 - 0.3 Volts
(E31) No. 1 - Body / 0 Volts

c. Start Engine, and idle it.
d. Measure voltage between ECM and body while Engine is idling.

Connector & Terminal / Specified Voltage:
(E3O) No. 5 - Body / 0.8 - 1.2 Volts
(E31) No. 1 - Body / 0 Volts

2. Check power supply to Mass Air Flow Sensor.
a. Turn Ignition Switch to "OFF".
b. Disconnect connector from Mass Air Flow Sensor.
c. Turn Ignition Switch to "ON".





d. Measure voltage between Mass Air Flow Sensor connector and body.

Connector & Terminal / Specified Voltage:
(E25) No. 1 - Body / 1O - 13 Volts

3. Check harness connector between ECM and Mass Air Flow Sensor.
a. Turn Ignition Switch to "OFF".
b. Disconnect connector from ECM.





c. Measure resistance of harness connector between ECM and Mass Air Flow Sensor.

Connector & Terminal / Specified Resistance:
(E3O) No. 5 - (E25) No. 2 / 10 Ohms, maximum
(E30) No. 22 - (E25) No. 3 / 10 Ohms, maximum
(E25) No. 3 - Body / 10 Ohms, maximum





d. Measure resistance of harness connector between ECM and body to make sure that circuit does not short.

Connector & Terminal / Specified Resistance:
(E3O) No. 5 - Body / 1 M-Ohm, minimum
(E31) No. 1 - Body / 1 M-Ohm, minimum