DTC P0125: ECT INSUFFICIENT TEMPERATURE FOR CLOSED LOOP OPERATION Isuzu Amigo II

Note. For circuit reference (Схема №5)

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

1. No MAP, IAT, ECT, TP, Misfire, Injector or VSS DTCs set.
2. Start-up IAT greater than 84°F (29°C).
3. Accumulated airflow is greater than 1500 grams.
4. Engine run time is more than 90 seconds.
5. On warm start-up, coolant and intake air temperature of 50°F (10°C), closed loop operation temperature of 84°F (29°C) not reached within 2 minutes of start-up.
6. On cold start-up, coolant temperature of 20°F (-10°C) and intake air temperature of 50°F (10°C), closed loop operation temperature of 84°F (29°C) not reached within 5 minutes of start-up.

Diagnostic Aids

Check coolant level. Ensure thermostat and cooling fans are operating properly. Check for high resistance in wiring related to ECT sensor. Check for skewed ECT sensor by comparing actual coolant temperature with scan tool display, and replace ECT sensor if temperatures are not close. Check for faulty connections or damaged harness. If connections and harness appear okay, observe scan tool while moving all related harnesses and connectors. A change in scan tool display may indicate fault location.