Toyota 2GR-FE Manual page 289

DTC P0100
DTC P0102
DTC P0103
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.
Open or short in Mass Air Flow (MAF) meter circuit for 3
P0100
seconds
Open in Mass Air Flow (MAF) meter circuit for 3
P0102
seconds
Short in Mass Air Flow (MAF) meter circuit for 3
P0103
seconds
2GR-FE ENGINE CONTROL SYSTEM – SFI SYSTEM
Mass or Volume Air Flow Circuit
Mass or Volume Air Flow Circuit Low Input
Mass or Volume Air Flow Circuit High Input
+B
Power Transistor
Platinum Hot Wire (Heater)
B
A
Output Voltage
Temperature Sensor (Thermistor)
DTC Detection Condition
Platinum Hot Wire (Heater)
Trouble Area
• Open or short in MAF meter circuit
• MAF meter
• ECM
• Open in MAF meter circuit
• Short in MAF meter circuit
• MAF meter
• ECM
• Short in MAF meter circuit (+B circuit)
• MAF meter
• ECM
ES–133
ES
A140749E04