Test Dr-3A - Testing Airflow Sensor (Code 12)
NOTE:
For connector terminal identification, see CONNECTOR IDENTIFICATION
. For appropriate wiring diagram, see WIRING DIAGRAMS
at end of article.
- Using DRB-II, erase faults. Start engine and idle for more than one minute. Read faults. If fault Code 12 displays again, go to step 3). If fault Code 12 does not display again, read airflow sensor value. While monitoring DRB-II display, wiggle airflow sensor wiring harness.
- If airflow sensor value changes, repair wiring harness that caused airflow sensor value to change, and perform TEST VER-2. If airflow sensor value does not change, perform TEST DR-15A.
- Read airflow sensor value. If airflow sensor value is zero Hz (one Hertz is equal to one cycle per second), go to step 5). If airflow sensor value is more than 10 Hz, replace ECU, and perform TEST VER-2. If airflow sensor value is NOT zero or more than 10 Hz, go to next step.
- Turn ignition off. Inspect vacuum hoses and air cleaner assembly for restrictions and leaks. Repair as required, and perform TEST VER-2. If no restrictions or leaks exist, replace airflow sensor, and perform TEST VER-2.
- Disconnect airflow sensor connector. If vehicle is turbocharged, go to next step. If vehicle is non-turbo, measure voltage at airflow sensor 6-pin connector terminal No. 2 (Red wire). If voltage is more than 10 volts, go to step 7). If voltage is less than 10 volts, repair open circuit in Red wire between airflow sensor and MPI control relay, and perform TEST VER-2.
- Measure voltage at airflow sensor 8-pin connector terminal No. 3 (Red wire). If voltage is more than 10 volts, go to next step. If voltage is less than 10 volts, repair open circuit in Red wire between airflow sensor and MPI control relay and perform TEST VER-1.
- On turbocharged vehicles, measure voltage at airflow sensor 8-pin connector terminal No. 2 (Green/Blue wire). On non-turbo vehicles, measure voltage at airflow sensor 6-pin connector terminal No. 1 (Green/Blue wire). On all vehicles, if voltage is less than 4 volts, go to next step. On all vehicles, if voltage is more than 10 volts, replace airflow sensor, and perform TEST VER-2.
- Turn ignition off. Disconnect ECU 24-pin connector. Measure resistance between ECU 24-pin connector terminal No. 10 (Green/Blue wire) and ground. If resistance is more than 10 ohms, go to next step. If resistance is less than 10 ohms, repair short to ground in Green/Blue wire, and perform TEST VER-2.
- Measure resistance of Green/Blue wire between ECU 24-pin connector terminal No. 10 and airflow sensor connector. If resistance is more than 10 ohms, repair open circuit in Green/Blue wire, and perform TEST VER-2. If resistance is less than 10 ohms, replace ECU, and perform TEST VER-2.