Code 23 - Mass Airflow Sensor
NOTE:
Refer to illustration for connector and terminal identification. See Figure
-Figure
.
- Ensure ECM is connected. Turn ignition on. Measure voltage between ECM connector E30, terminal No. 5 (backprobe) and ground. Voltage should be 0-.3 volt. Measure voltage between ECM connector E31, terminal No. 1 and ground. No voltage should be present.
- Start and idle engine. About .8-1.2 volts should now be present between ECM connector E30, terminal No. 5 and ground. Zero voltage should be present between ECM connector E31, terminal No. 1 and ground. If voltages are to specification, repair ECM harness connector or replace ECM. If voltages are not to specification, go to next step.
- Turn ignition off. Disconnect MAF sensor connector. Turn ignition on. Measure voltage between MAF sensor connector terminal No. 1 (Yellow/Green wire) and ground. If voltage is 10-13 volts, go to next step. If voltage is not 10-13 volts, repair or replace MAF harness or connector.
- Turn ignition off. Disconnect ECM connector. Measure resistance between ECM connector E30, terminal No. 5 and MAF connector terminal No. 2 (Black/Blue wire), between ECM connector E30, terminal No. 22 and MAF connector terminal No. 3 (Black/Red wire), and between MAF connector terminal No. 3 (Black/Red wire) and ground. A maximum of 10 ohms should be present in all cases. If more than 10 ohms is present in any case, repair harness as necessary.
- Measure resistance between ECM connector E30, terminal No. 5 and ground, and between ECM connector E31, terminal No. 1 and ground. A minimum of one megohm should be present in both cases. If resistances are to specification, replace MAF sensor. If resistances are not to specification, repair or replace harness.