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 ): Testing and Inspection

Note: Applies to Engine Coolant Temperature Sensor (ECTS) and Intake Air Temperature Sensor (IATS).

- The IATS should be tested in air; the ECTS can be tested in water.
- The temperature of the component should be measured with an accurately calibrated thermometer. Be sure that the temperature of the component has stabilized. Using a DMM set to ohms measure the resistance across the connector blades.

Temperature Chart:





- Compare the reading obtained to chart; the resistance should be within the band.
- If the reading falls outside the band, recheck temperature and resistance measurement. Check each pin to the component case, the resistance should be very high (infinity).
- Replace components which fall outside of the tolerance.