Intake Air Temperature Sensor
2017 Toyota Corolla · 1.8L I4
Sensor Type
thermistor
Waveform Type
dc-variable
Location
Integrated into MAF sensor housing on air intake tube between air filter and throttle body
Pins
2-pin connector
Timebase
1s/div
Voltage Scale
1V/div
Trigger
Not applicable for DC measurement
Wiring
Light blue wire (signal to ECM terminal THA), Black wire (sensor ground E2)
Expected Voltage Range
At Idle
1.5V to 3.5V
At Higher RPM
1.2V to 3V
Expected Pattern
Steady DC voltage inversely proportional to intake air temperature, negative temperature coefficient
Known-Good Waveform
At ambient temperature of 68°F, expect 2.0-2.5V signal. As intake air heats up during operation or in hot engine bay, voltage decreases to 1.5-2.0V. Signal should remain stable without noise or erratic fluctuations during acceleration.
Common Failure Patterns
Voltage stuck at 4.5-5.0V constantly
Cause: Open circuit in IAT sensor element or wiring, corroded connector pins at MAF sensor
Voltage reads near 0V
Cause: Short to ground in sensor circuit or failed thermistor
Related DTCs: P0112
Intermittent voltage spikes or dropouts
Cause: Contaminated MAF sensor affecting IAT element, loose connector at MAF housing
Related DTCs: P0113
Diagnostic Tips
IAT is built into the MAF sensor assembly on 2ZR-FE engines - replacement requires entire MAF unit. Check for oil contamination from over-oiled aftermarket air filters which commonly affects this sensor.
Related Diagnostic Trouble Codes
P0110P0111P0112P0113P0114
Always confirm waveform data with your vehicle's OEM service manual before diagnosing.
Free, no signup. View all waveforms for this vehicle