| WARNING | Read service precautions before proceeding with service procedure. See SERVICE PRECAUTIONS . |
Circuit Description
Mass Airflow (MAF) meter uses a platinum hot wire which is maintained at a constant temperature by controlling the current flow through the hot wire. Current flow is then measured as an output voltage. MAF meter may also be referred to as airflow meter. DTC is set when ECM detects MAF meter output is greater than 2.91 volts with Throttle Position (TP) sensor VTA circuit signal voltage of .42-.86 volt with engine coolant temperature greater than 158°F (70°C) for more than 10 seconds with engine speed of 1500 RPM or less, or MAF meter output is less than one volt with TP sensor VTA circuit signal voltage of 3 volts or more for more than 10 seconds with engine speed of 2100 RPM or more. Possible cause is defective MAF meter.
Diagnostic Aids
Using Toyota hand-held tester or scan tool, read FREEZE FRAME data. Freeze frame data records engine conditions when malfunction is detected.