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:
Front suspension arm sub–assy lower no.1 Lh
Replacement
Hint: components:
1. Remove front wheel
2. Disconnect front stabilizer link assy lh (lh (a/t) position)
3. Disconnect front stabilizer link assy rh (lh (a/t) position)
Hint:
remove the rh side by the same procedures as the lh side.
4. Separate front suspension arm sub–assy lowe ...
Removal and installation of fuel control parts
Place for removing and installing of fuel system parts
work in a place with good air ventilation and without anything
flammable such as welder, grinder,
drill, electric motor or stove in the surroundings.
Never work in a place such as a pit or nearby a pit, as there is a ...
Replacement
1. Remove combination meter assembly
2. Disconnect brake master cylinder push rod clevis
remove the clip and push rod clevis pin and wave washer, and
disconnect the push rod clevis from
the brake pedal.
3. Remove brake pedal support sub–assy
Remove the bolt from the bra ...