Toyota 2GR-FE Manual page 300

ES–144
DTC
DTC
DTC
DESCRIPTION
ES
The Intake Air Temperature (IAT) sensor, mounted on the Mass Air Flow (MAF) meter, monitors the IAT.
The IAT sensor has a built-in thermistor with a resistance that varies according to the temperature of the
intake air. When the IAT drops, the resistance of the thermistor increases. When the temperature rises,
the resistance drops. These variations in resistance are transmitted to the ECM as voltage changes (See
Fig. 1).
The IAT sensor is powered by a 5 V supply from the THA terminal of the ECM, via resistor R.
Resistor R and the IAT sensor are connected in series. When the resistance value of the IAT sensor
changes, according to changes in the IAT, the voltage at terminal THA also varies. Based on this signal,
the ECM increases the fuel injection volume when the engine is cold to improve driveability.
HINT:
When any of DTCs P0110, P0112 and P0113 are set, the ECM enters fail-safe mode. During fail-safe
mode, the IAT is estimated to be 20°C (68°F) by the ECM. Fail-safe mode continues until a pass condition
is detected.
DTC No.
P0110
P0112
P0113
2GR-FE ENGINE CONTROL SYSTEM – SFI SYSTEM
P0110 Intake Air Temperature Circuit Malfunction
P0112 Intake Air Temperature Circuit Low Input
P0113 Intake Air Temperature Circuit High Input
Fig. 1
Resistance
(kΩ)
Proceed to DTC Detection Condition
Open or short in Intake Air Temperature (IAT)
Step 1 sensor circuit for 0.5 seconds
(1 trip detection logic)
Short in Intake Air Temperature (IAT) sensor
Step 4
circuit for 0.5 seconds (1 trip detection logic)
Open in Intake Air Temperature (IAT) sensor
Step 2
circuit for 0.5 seconds (1 trip detection logic)
Acceptable
(°C)
Temperature
(°F)
A067628E20
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Trouble Area
Open or short in IAT sensor circuit
IAT sensor (built into MAF meter)
ECM
Short in IAT sensor circuit
IAT sensor (built into MAF meter)
ECM
Open in IAT sensor circuit
IAT sensor (built into MAF meter)
ECM