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Home >> Chevrolet >> 2013 >> Tahoe LS, RWD >> Repair and Diagnosis >> External Pages >> Different car >> Section 2022 (Engine Controls/Fuel - 5.3L, 6.0L, 6.2L - DTC P0442 To DTC P3449 And Diagnostic Information And Procedures) >> Diagnostic Information and Procedures >> Cylinder Deactivation (Active Fuel Management) System Diagnosis >> Circuit Description

Circuit Description

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To provide maximum fuel economy under light load driving conditions, the engine control module (ECM) will command the valve lifter oil manifold (VLOM) solenoids ON, to deactivate engine cylinders 1 and 7 on the left bank, and cylinders 4 and 6 on the right bank. The VLOM consists of 4 electrically operated normally closed solenoids, which directs pressurized engine oil to 8 deactivating valve lifters. All 4 VLOM solenoids are connected in parallel to a fused ignition circuit supplied by the powertrain relay. The control circuit for each solenoid is connected to an individual low side driver internal to the ECM. When enabling conditions for V4 mode are met, the ECM will command each low side driver to turn ON, in engine firing order sequence.