Toyota 2GR-FE Manual page 297

DTC P0101
DESCRIPTION
The Mass Air Flow (MAF) meter is a sensor that measures the amount of air flowing through the valve.
The ECM uses this information to determine the fuel injection time and to prove appropriate air-fuel ratio.
Inside the MAF meter, there is a heated platinum wire which is exposed to the flow of intake air.
By applying a specific electrical current to the wire, the ECM heats it to a given temperature. The flow of
incoming air cools both the wire and an internal thermistor, affecting their resistance. To maintain a
constant current value, the ECM varies the voltage applied to these components in the MAF meter. The
voltage level is proportional to the airflow through the sensor, and the ECM uses it to calculate the intake
air volume.
The circuit is constructed so that the platinum hot wire and the temperature sensor provide a bridge
circuit, and the power transistor is controlled so that the potentials of A and B remain equal to maintain the
predetermined temperature.
HINT:
When any of these DTCs are set, the ECM enters fail-safe mode. During fail-safe mode, the ignition
timing is calculated by the ECM, according to the engine RPM and throttle valve position. Fail-safe mode
continues until a pass condition is detected.
Temperature Sensor
(Thermistor)
DTC No.
Test value calculated with engine load and fuel trim are
out of specified threshold under the following conditions
(2 trip detection logic):
P0101
–
–
2GR-FE ENGINE CONTROL SYSTEM – SFI SYSTEM
Mass Air Flow Circuit Range / Performance
Problem
+B
Power Transistor
Platinum Hot Wire (Heater)
A B
Output Voltage
Temperature Sensor (Thermistor)
DTC Detection Condition
Engine load is 30 % or more and constant
Engine coolant temperature is 70°C (158°F) or
higher
Platinum Hot Wire (Heater)
Trouble Area
MAF meter
ES–141
ES
A140749E05