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Home >> Hummer >> 2008 >> H2 4D Utility Pickup >> Repair and Diagnosis >> Engine Performance >> System >> Engine Controls And Fuel - 6.2L - DTC P1255 To DTC P2635 >> DTC P1258 >> Circuit/System Description
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Circuit/System Description

The engine control module (ECM) uses the engine coolant temperature (ECT) sensor to monitor the engine for an over-termperature condition. This condition occurs when the coolant temperature is above a calibrated value for a calibrated length of time. The ECM will disable half of the cylinders by turning OFF the fuel injectors. By disabling half of cylinders, the ECM is able to reduce the temperature of the coolant.