Circuit Description

While engine is warming, PCM reads Engine Coolant Temperature (ECT) sensor to determine how long it takes coolant to reach temperature required for closed loop operation. PCM compares actual time required to a predetermined time.

Conditions required to set DTC are:

• No MAP, IAT, ECT, TP, Misfire, Injector or VSS DTCs set.
• Start-up ECT less than 84°F (29°C).
• Start-up IAT greater than 50°F (10°C).
• Accumulated airflow is greater than 1500 grams.
• Engine run time is more than 90 seconds.