Operation CHARM: Car repair manuals for everyone.
Manuals through 2025 now available!

Our trusted friends have launched a new website named LEMON, which has newer manuals. It also contains all the CHARM manuals.

LEMON is the spiritual successor to CHARM, I recommend you try it!

Link: lemon-manuals.la or lemon-manuals.org.ua

(Some people have issue connecting. LEMON is investigating. For now, use Firefox or change your DNS server)

Or, hide this message: temporarily or permanently

Air Temperature Sensor ( Ambient / Intake ): Description and Operation

Intake Air Thermosensor:






PURPOSE
Measure temperature of intake air and provide ECU with signal used in regulating fuel injection quantity, idle speed, and ignition timing.

LOCATION
In intake manifold runner.

OPERATION
Thermosensor is a negative temperature coefficient thermistor. This means as temperature increases, resistance decreases. Cold air is more dense than warm air. The ECU measures thermosensor resistance via a reference voltage to calculate intake air temperature.

TEMPERATURE / RESISTANCE (K OHMS)

68°F (20°C) / 2.2K - 2.7K
176°F (80°C) / 0.29K - 0.35K