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DTC P0111 Intake Air Temperature Sensor 1 Circuit Range / Performance: Description

Fig 1: Temperature Versus Resistance Graph
G05751472Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

The intake air temperature sensor, in the mass airflow meter, monitors the intake air temperature The intake air temperature sensor has a built-in thermistor with a resistance that varies according to the temperature of the intake air When the intake air temperature is low, the resistance of the thermistor increases When the temperature is high, the resistance drops These variations in resistance are transmitted to the ECM as voltage changes (see Fig 1).

The intake air temperature sensor is powered by a 5 V supply from the THA terminal of the ECM, via resistor R.

Resistor R and the intake air temperature sensor are connected in series When the resistance value of the intake air temperature sensor changes, according to changes in the intake air temperature, the voltage at terminal THA also varies. Based on this signal, the ECM increases the fuel injection volume when the engine is cold to improve driveability

DTC DETECTION CONDITION CHART

DTC No. DTC Detection Condition Trouble Area
P0111 When either of the following conditions is met (2 trip detection logic)
  • The intake air temperature rise is small, from the previous trip warm-up to the following trip
  • When the change in the intake air temperature after engine start is less than the threshold value
  • Mass air flow meter