Engine Is Cold Too Long

WHEN MONITORED
With the engine temperature between -20°F and +21 2°F at start up, coolant sensor operating, the engine running for at least 12 minutes, and the vehicle speed above 28 mph.

SET CONDITION
All monitoring conditions are met and the engine temperature does not reach 1 74°F after 20 minutes.

THEORY OF OPERATION

The engine thermostat is designed to maintain the engine at or near the design temperature to promote maximum efficiency.

PROBABLE CAUSES
- Extreme cold outside temperature
- Failed thermostat
- Coolant sensor out of calibration