Engine Coolant Temperature Sensor
- A malfunction in Engine Coolant Temperature (ECT) sensor circuit can set a DTC. For testing procedures and specifications, perform appropriate diagnostic test. See DIAGNOSTIC TROUBLE CODE DEFINITIONS
in SELF-DIAGNOSTICS - 3.2L CTS article.
- Disconnect ECT sensor harness connector. Using DVOM, measure resistance of ECT sensor at specified temperatures. See Fig 1
. Resistance should be high when engine is cold and drop as engine warms. With vehicle sitting overnight, Intake Air Temperature (IAT) sensor and ECT sensor should have close to the same resistance reading. If resistance is not within specification, replace ECT sensor. See ENGINE COOLANT TEMPERATURE SENSOR
under SENSORS in REMOVAL & INSTALLATION article.
Courtesy of GENERAL MOTORS CORP.