Toyota Corolla (E120) 2002–2008 Repair Manual / Diagnostics / Sfi system / Intake air temperature circuit / Circuit description
Toyota Corolla (E120): Circuit description
The intake air temperature (iat) sensor, mounted on the mass air flow (maf) sensor, 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 temperature is high, the resistance drops. The variations in resistance are reflected 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 intake air temperature sensor from terminal tha (thar) via 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 (thar) also changes. Based on this signal, the ecm increases the fuel injection volume to improve the drive ability during cold engine operation.
|
Dtc no. |
Proceed to |
Dtc detection condition |
Trouble area |
| P0110 | Step 1 | Open or short in intake air temperature sensor circuit for 0.5 Seconds |
|
| P0112 | Step 4 | Short in intake air temperature sensor circuit for 0.5 Seconds | |
| P0113 | Step 2 | Open in intake air temperature sensor circuit for 0.5 Seconds |
Hint
: after confirming dtc p0110, p0112 or p0113, confirm the intake air temperature in the ”diagnosis / enhanced obd ii / data list / all” using the hand–held tester or the obd ii scan tool.
Monitor description
The ecm monitors the sensor voltage and uses this value to calculate the intake air temperature. When the sensor output voltage deviates from the normal operating range, the ecm interprets this as a fault in the iat sensor and sets a dtc.
Example: when the sensor voltage output equal to –40 c (–40 °F) or more than 140 c (284 °F).
Monitor strategy
Typical enabling conditions
Typical malfunction thresholds
Component operating range
Wiring diagram
Other materials:
Using the storage features
List of storage features
1 Glove box
2 Bottle holders
3 Console box
4 Cup holders
CAUTION
■Items that should not be left in the storage spaces
Do not leave glasses, lighters or spray cans in the storage spaces, as this
may cause the following when cabin temperature becomes high: ...
Rear suspension
Preparation
Sst
Recomended tools
Equipment
Tire & wheel
Preparation
Equipment
...
Initialization
1. Reset memory
Caution:
perform the reset memory (at initialization) when replacing the automatic
transaxle assy, engine
assy or ecm.
Notice:
hand–held tester only
Turn the ignition switch off.
connect the hand–held tester to the dlc3.
turn the ignition switch to th ...