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Home >> Hummer >> 2008 >> H2 4D Utility Wagon >> Repair and Diagnosis >> External Pages >> Different car >> Section 508 (Engine Controls/Fuel - 5.3L, 6.0L, 6.2L - DTC P0420 To DTC P3449 And Diagnostic Information And Procedures) >> Diagnostic Information and Procedures >> DTC P3401, P3425, P3441, or P3449 >> Circuit/System Description

Circuit/System Description

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The cylinder deactivation system is used to deactivate 4 cylinders of the engine under light load driving conditions. The engine control module (ECM) commands the cylinder deactivation solenoids ON to deactivate engine cylinders 1, 7, 6, and 4, switching to 4 cylinders or V4 mode. The cylinder deactivation solenoids controls the oil flow to the appropriate valve lifters. The engine operates on 8 cylinders or V8 mode, during engine starting, engine idling, and medium to heavy throttle conditions.

Ignition voltage is supplied directly to the 4 cylinder deactivation solenoids. The engine control module (ECM) controls the 4 cylinder deactivation solenoids by grounding the control circuit with a solid state device called a driver.

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