DTC Confirmation Test
NOTE:
For best results, perform test with ambient temperature at 14°F (-10°C) or more and engine coolant temperature 14-140°F (-10-60°C).
Malfunction is detected when engine coolant temperature does not reach a specified temperature, even though engine has been running for a specified time. Possible causes are:
- Stuck open thermostat.
- Thermostat seal leaking.
- Defective Engine Coolant Temperature (ECT) sensor.
To set DTC, replace thermostat using an OEM thermostat. Turn ignition on. Select COOLAN TEMP/S in DATA MONITOR with scan tool and observe engine coolant temperature. Ensure engine coolant temperature is less than 140°F (60°C). Drive vehicle at 50-75 MPH for 10 consecutive minutes. If first trip DTC is detected, go to PROCEDURE .