Toyota 1 MZ–FE Manual page 451

DTC P0110 Intake Air Temp Circuit Malfunction
CIRCUIT DESCRIPTION
The intake air temp. sensor is built into the air flow meter and
senses the intake air temperature.
A thermistor built in the sensor changes the resistance value
according to the intake air temperature.
The lower the intake air temperature, the greater the thermistor
resistance value, and the higher the intake air temperature, the
lower the thermistor resistance value (See Fig. 1.).
The intake air temperature sensor is connected to the ECM
(See next page). The 5V power source voltage in the ECM is
applied to the intake air temperature sensor from the terminal
THA via a resistor R.
That is, the resistor R and the intake air temperature sensor are
connected in series. When the resistance value of the intake air
temperature sensor changes in accordance with changes in
the intake air temperature, the potential at terminal THA also
changes. Based on this–signal, the ECM increases the fuel
injection volume to improve driveability during cold engine
operation.
If the ECM records the diagnostic trouble code "P0110", it
operates the fail safe function in which the intake temperature
is assumed to be 20 C (68 F). Intake Air Ter
Diagnostic Trouble Code Detecting Condition
DTC No.
Open or short in intake air temp. sensor circuit.
P0110
Hint; After confirming DTC P01 10 use the OBDII scan tool or TOYOTA hand–held tester to confirm the
intake air temperature from "CURRENT DATA".
1MZ–FE ENGINE
Temperature Displayed
– 40 C (–40 F)
120 C (248 F) or more
– CIRCUIT INSPECTION
(Reference )
Intake Air Temp.
°C (° F)
Trouble Area
Open or short in intake air temp. sensor circuit.
Intake air temp. sensor
ECM
Malfunction
Open circuit
Short circuit
EG2–451
Resistance Voltage
(kW) M