Mass Airflow (MAF) Sensor
- Start and warm engine to operating temperature. Measure CO content. If CO content is more than 6 percent, it is too far out of range to be adjusted with mass airflow sensor adjuster screw (if equipped). Inspect filament wire. If wire is broken, replace MAF sensor.
- Turn ignition off. Unplug connector from mass airflow sensor. Check for continuity between harness connector terminal No. 1 and ground. See Fig 1
. If continuity does not exist, repair Black wire between terminal No. 1 and ground terminal on intake manifold.
- Measure resistance between pins No. 3 and 6 on MAF sensor. Resistance should be about 380 ohms. If resistance is not as specified, turn adjuster screw (if equipped) until this resistance can be obtained. If this reading cannot be obtained, replace mass airflow sensor.
- Reconnect wiring to mass airflow sensor. Turn ignition on. Check for battery voltage at terminal No. 5 (Brown/White wire) of harness connector. If battery voltage does not exist, repair Brown/White wire between connector and pin No. 87B (Brown/White wire) of system main relay.
- Turn ignition off. Check for continuity between MAF sensor harness connector pin No. 2 (Blue/White wire) and ECM pin No. 6 (Blue/White wire). If continuity does not exist, repair Blue/White wire.
- Clear codes. Drive vehicle. Measure CO level. If code resets, temporarily substitute known good mass airflow sensor. If code still resets, temporarily substitute known good ECM. Retest system.
Courtesy of SAAB-SCANIA OF AMERICA, INC.