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Home >> Lexus >> 2008 >> GX 470 >> Repair and Diagnosis >> Engine Performance >> Engine Control System >> SFI System >> DTC P0110 Intake Air Temperature Circuit; DTC P0112 Intake Air Temperature Circuit Low Input; DTC P0113 Intake Air Temperature Circuit High Input >> Description

DTC P0110 Intake Air Temperature Circuit; DTC P0112 Intake Air Temperature Circuit Low Input; DTC P0113 Intake Air Temperature Circuit High Input: Description

Fig 1: Intake Air Temperature Graph
G04967813Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

The Intake Air Temperature (IAT) sensor, built into the Mass Air Flow (MAF) meter, monitors the intake air temperature. The IAT sensor has a thermistor that varies its resistance depending on the intake air temperature. When the intake 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 IAT sensor is connected to the ECM. The 5 V power source voltage in the ECM is applied to the IAT sensor from terminal THA via resistor R.

The resistor R and the IAT sensor are connected in series. When the resistance value of the IAT sensor changes in accordance with changes in the intake air temperature, the voltage at terminal THA (THAR) also changes. Based on this signal, the ECM increases the fuel injection volume to improve driveability during cold engine operation.

DTC DETECTION CONDITION CHART

DTC No. DTC Detection Condition Trouble Area
P0110 Open or short in IAT sensor circuit for 0.5 seconds
  • Open or short in Intake Air Temperature (IAT) sensor circuit
  • Intake Air Temperature (IAT) sensor (built into Mass Air Flow [MAF] meter)
  • ECM
P0112 Short in IAT sensor circuit for 0.5 seconds
  • Short in IAT sensor circuit
  • IAT sensor (built into MAF meter)
  • ECM
P0113 Open in IAT sensor circuit for 0.5 seconds
  • Open in IAT sensor circuit
  • IAT sensor (built into MAF meter)
  • ECM

HINT:

After confirming DTC "P0110, P0112 or P0113", use the Techstream to confirm the intake air temperature in the "Powertrain/Engine and ECT/Data List/All Data/Intake Air".

TEMPERATURE DISPLAYED CHART

Temperature Displayed Malfunction
-40°C (-40°F) Open circuit
140°C (284°F) Short circuit