Toyota ZZT230 series Repair Manual page 239

Dl-28
DTC P0110
CIRCUIT DESCRIPTION
(flg.1)
m '
5i '
g
J!l '
!!1
lil "
a: u
-20 o 20 40
32 6B liM
(-4)
Temp."C (F")
OTCNo.
Open
P0110 short in intake
or
P0110,
HINT:
After confirming DTC afr
temperature from CURRENT DATA.
Tempare!Ure Displayed
"
C ( -40
-40
140·c
Intake Air Temp. Circuit Malfunction
The intake air temp. sensor is built into the mass 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 flg.1 ).
The air Intake temperature sensor is connected to the ECM (See below). The 5 V power source voltage in the ECM is ap­
plied to the intake air temp. sensor from the terminal
a resistor R.
That is, the resistor R and the intake air temp. sensor are con­
nected in series. When the resistance value of the intake air
temp. sensor changes in accordance with changes in the intake
eo ao 100
air temperature, the potential at terminal THA also changes .
HO
Based on this signal, the ECM increases the fuel injection vol­
fl4741 ume to improve drlveability during cold engine operation.
176 212
If the ECM detects the DTC
0
function in which the intake air temperature Is assumed to be
2 C (68"F)
"
DTC Detecting
Condition
air temp. sensor
circuit
II
use the OBD scan tool or TOYOTA hand-held tester to confirm the intake
" F)
or more
-
"P0110",
or short In
•Open Intake air temp. sensor circuit
• Intake air temp.
sensor
•ECM
Malfunction
Open circuit
Short circuit
THA
tt
operates the fail safe
Trouble Area
(built
Into mass air meter)
flow
via