Solstice 2006-2008, Sky 2007-2008

Variable Camshaft Timing Oil Control Solenoid



The Camshaft Position (CMP) actuator system is controlled by the control module. The control module sends a pulse width modulated 12-volt signal to each CMP actuator solenoid to control the amount of engine oil flow to a camshaft actuator passage. There are 2 different passages for oil to flow through, a passage for camshaft advance and a passage for camshaft retard. The camshaft actuator is attached to each camshaft and is hydraulically operated to change the angle of each camshaft relative to Crankshaft Position (CKP). Engine Oil Pressure (EOP), viscosity, temperature, and engine oil level can affect camshaft actuator performance. The control module calculates the optimum camshaft position through the following inputs:

Engine speed
Manifold Absolute Pressure (MAP)
Throttle position indicated angle
Engine load
Barometric Pressure (BARO)

A locking pin keeps the CMP actuators in the parked position to avoid valve train noise upon engine start-up. The parked position is 0 degrees of camshaft actuation. The locking pin will release the actuator after the EOP is sufficient to overcome the locking pin spring pressure. The exhaust CMP actuators also have return springs. The return springs are necessary to assist the CMP actuators to return to the parked position due to the rotational inertia of the valve train components upon engine shutdown. The control module uses the following inputs before assuming control of the CMP actuator:

Engine Coolant Temperature (ECT)
Closed loop fuel control
Engine oil temperature (EOT
Engine oil level
CMP actuator solenoid circuit state
Ignition 1 signal voltage

Removal & Installation

  1. Remove the intake manifold cover.
  3. Disconnect the engine harness electrical connectors from the Camshaft Position (CMP) actuator solenoid valves.
  5. Remove the exhaust CMP actuator solenoid valve bolt and valve, if required.
  7. Remove the intake CMP actuator solenoid valve bolt and valve, if required.
  9. Inspect the solenoid valve O-ring seals for damage, replace as necessary.

To Install:

  1. Lubricate the solenoid valve O-ring seals with clean engine oil.
  3. Install the intake CMP actuator solenoid valves and bolts, tighten to 89 inch. lbs. (10 Nm).
  5. Connect the engine harness electrical connector to the appropriate CMP actuator solenoid valves.
  7. Install the intake manifold cover.


  1. Ignition OFF, disconnect the Camshaft Position (CMP) actuator solenoid harness connector at the CMP actuator solenoid.
    Ensure component is tested at 20°C (68°F).

  3. Test for 4.6-7.5 ohms of resistance between the high control terminal no. A and the low reference terminal no. B of the CMP actuator solenoid.
  5. If the resistance is not within the specified range, replace the CMP actuator solenoid.

    Click image to see an enlarged view

    Fig. Camshaft Position (CMP) actuator solenoid -intake Electrical connector

    Click image to see an enlarged view

    Fig. Camshaft Position (CMP) actuator solenoid - exhaust Electrical connector