Intake Air Temperature Sensor
2021 Honda Civic · 1.5L I4 Turbo
Sensor Type
thermistor
Waveform Type
dc-variable
Location
Integrated into Mass Air Flow sensor assembly in air intake duct between air filter and turbocharger inlet
Pins
2-pin connector
Timebase
1s/div
Voltage Scale
1V/div
Trigger
Free run
Wiring
Yellow/White (signal) and Green/White (ground) - shared ground with other sensors
Expected Voltage Range
At Idle
1.8V to 2.5V
At Higher RPM
1.5V to 2V
Expected Pattern
Steady DC voltage inversely proportional to intake air temperature, negative temperature coefficient
Known-Good Waveform
At ambient temperature (68°F), expect 2.0-2.5V. Under boost or hot soak conditions, voltage decreases to 1.5-1.8V. Signal should be rock-steady with minimal noise, changing only gradually with temperature variations during driving.
Common Failure Patterns
Voltage fixed at 4.9-5.0V
Cause: Open circuit in IAT sensor element or broken wire
Diagnostic Tips
On turbo Civics, IAT sensor failure often accompanies MAF contamination from oiled aftermarket air filters. Check for oil residue. Resistance should be approximately 2.5kΩ at 68°F. IAT directly affects boost control and knock management.
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