Note. For component location, see appropriate illustration in THEORY & OPERATION article.
Circuit Description
MAF meter uses a platinum hot wire maintained at a constant temperature. Airflow past meter affects temperature and current flow through MAF meter. DTC is set when ECM detects either throttle valve is fully closed and MAF meter output is more than 2.2 volts for more than 10 seconds with engine speed of 900 RPM or less, or VTA circuit signal is .63 volt or more and MAF meter output is less than 1.06 volts for more than 10 seconds with engine speed of 1500 RPM or more. ECM will operate in fail-safe mode if DTC P0101 is set. Possible cause is
- Defective MAF meter.
Diagnostic Aids
After confirming DTC P0101, use scan tool to access CURRENT DATA to confirm mass airflow ratio. If ratio is 0.0 gm/sec., VG circuit may be open or shorted or power source circuit may be open. If ratio is 271.0 gm/sec. or more, E2G circuit may be open. Using scan tool, read freeze frame data. Freeze frame records engine conditions when malfunction is detected.