Toyota Celica 2005 Repair Manual page 574

DTC P0110
DTC P0112
DTC P0113
CIRCUIT DESCRIPTION
Fig. 1
30
20
10
1
0.1
20
0
− 20
(32) (68)
(− 4)
Temp. °C (°F)
DTC No. Proceed to
P0110 Step 1
P0112 Step 4
P0113 Step 2
HINT:
After confirming DTC "P0110, P0112 or P0113", use the hand−held tester or the OBD II scan tool to confirm
the intake air temperature in the "DIAGNOSIS / ENHANCED OBD II / DATA LIST / ALL".
Temperature Displayed
140°C ( 284°F ) or more
2005 CELICA (RM1131U)
DIAGNOSTICS
Intake Air Temperature Circuit
Intake Air Temperature Circuit Low Input
Intake Air Temperature Circuit High Input
Acceptable
40 60 80 100
(104) (140) (176) (212)
A15475
DTC Detection Condition
Open or short in intake air
temperature sensor circuit for
0.5 sec.
Short in intake air tempera-
ture sensor circuit for 0.5 sec.
Open in intake air tempera-
ture sensor circuit for 0.5 sec.
−40°C (−40°F)
− ENGINE (2ZZ−GE)
The intake air temperature (IAT) sensor, mounted on the mass
air flow (MAF) meter, monitors the intake air temperature. The
IAT sensor has a thermistor that varies its resistance depending
on the temperature of the intake air. When the air temperature
is low, the resistance in the thermistor increases. When the tem-
perature is high, the resistance drops. The resistance varies as
voltage changes to the ECM terminal. (See Fig. 1).
The intake air temperature sensor is connected to the ECM.
The 5 V power source voltage in the ECM is applied to the in-
take air temperature sensor from terminal THA (THAR) via re-
sistor 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 (THAR)
also changes. Based on this signal, the ECM increases the fuel
injection volume to improve the driveability during cold engine
operation.
S Open or short in intake air temperature sensor circuit
S Intake air temperature sensor (built in mass air flow meter)
S ECM
573
Trouble Area
Malfunction
Open circuit
Short circuit
DI−375
DI37Z−18