Valve Lifter Oil Solenoid Valve
The cylinder deactivation system uses an electro-hydraulic actuator device called the valve lifter oil solenoid. The valve lifter oil solenoid is bolted to the top of the cylinder head valve covers. Each solenoid controls the application of engine oil pressure to the intake and exhaust valve lifters on the cylinders selected to deactivate. Engine oil pressure is routed to the valve lifter oil solenoid from an internal oil passages.
Both valve lifter oil solenoids are connected in parallel to a fused ignition 1 voltage circuit, supplied by the ignition relay. The ground or control circuit for each solenoid is connected to a low side driver internal to the Engine Control Module (ECM).
When all enabling conditions are met for cylinder deactivation, the ECM will ground each solenoid control circuit in firing order sequence, allowing current to flow through the solenoid windings. With the coil windings energized, the solenoid controls engine oil pressure through the valve lifter. When vehicle-operating conditions require a return to V6 mode, the ECM will turn OFF the control circuit for the solenoids, allowing the solenoid valves to close. With the solenoid valves closed, engine oil pressure in the control ports is exhausted through the body of the solenoids into the engine.
During service, use extreme care in keeping the valve lifter oil solenoid free of any contamination or foreign material.
Cylinder deactivation may be inhibited for many reasons including the following:
- Engine coolant temperature out of range for cylinder activation
- Engine vacuum out of range
- Brake booster vacuum out of range
- Transmission gear incorrect or shift in progress
- Accelerator pedal out of range or rate of pedal application to fast
- Engine oil pressure and temperature out of range
- Engine speed out of range
- Vehicle speed out of range
- Minimum time in V6 mode not met
- Maximum V4 mode time exceeded
- Decel fuel cutoff is active
- Reduced engine power is active
- Torque management is active
- Catalytic converter over temperature protection is active
- Piston protection is active, knock detected
- Cylinder deactivation solenoid driver circuit faults