| CAUTION | If ECM replacement is instructed in following testing, always ensure ECM connectors and ground circuit are okay. If either are suspect, repair and repeat testing to confirm ECM malfunction. |
Circuit Description
MAF sensor uses a platinum hot wire maintained at a constant temperature. Airflow past sensor affects temperature and current flow through sensor. DTC is set when ECM detects an open or short in MAF sensor circuit for more than 3 seconds with engine speed at 4000 RPM or less. ECM will operate in fail-safe mode if DTC P0100 is set. Possible causes are
- MAF open or short circuit.
- MAF sensor.
- ECM.
Note. For information on engine immobilizer system, see COMPUTERIZED ENGINE CONTROLS in THEORY & OPERATION article.