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Home >> Chevrolet >> 2002 >> Blazer 4D Utility, 4WD, Part Time >> Repair and Diagnosis >> External Pages >> Different car >> Section 907 (Engine Cooling System) >> Diagnostic Information and Procedures >> DTC P1258: Coolant Temperature High >> Circuit Description

Circuit Description

WARNING: This page is about a different car, the 2003 GMC Sonoma, 2003 GMC Jimmy, 2003 Chevrolet S10 Pickup, and 2003 Chevrolet Blazer. However, it is still accessible from the selected car via links, so may be relevant.

The PCM uses the ECT sensor to monitor the engine for an over temperature condition. This condition occurs when the coolant temperature is above 132°C (270°F). When an over temperature condition is present, DTC P1258 will set. The PCM will alternately disable 4 injectors. By alternately disabling 4 injectors, the PCM is able to reduce the temperature of the coolant.

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