Mechanical Inspection

Camshaft Position Actuators

Fig 1: Locating Intake Camshaft Position Actuator Inner Rotor Hub & Outer Housing
Courtesy of GENERAL MOTORS CORP.
CAUTION: When removing, handling or installing this component wear protective gloves. The sharp edges on the component may be very sharp and may cause injury.
NOTE: DO NOT clamp the component in any clamping device such as a vise or gripping tool. Clamping the component can cause external and internal damage that can affect engine and/or component performance.
1. Inspect the intake camshaft position actuator to ensure the internal lock pin is engaged and the camshaft position actuator is parked in the home position. Attempt to rotate the inner rotor hub (1) within the outer housing (2).

   If the intake camshaft position actuator can be turned in either direction the camshaft position actuator must be replaced.

Fig 2: Locating Intake Camshaft Position Actuator External Housing Locking Pin Cover
Courtesy of GENERAL MOTORS CORP.
2. Locate the internal hub oil passage for the locking pin by observing the external housing locking pin cover (1). The oil passage in the hub for the locking pin is inline with the location of the locking pin cover.
Fig 3: Locating Intake Camshaft Position Actuator Internal Lock Pin
Courtesy of GENERAL MOTORS CORP.
3. Inspect the intake camshaft position actuator for smooth and even movement. Using a pre-bent hex key, smaller than the oil passage, depress the internal lock pin through the oil passage (1) located within the hub of the camshaft position actuator. While viewing the intake camshaft position actuator from the front and with the lock pin depressed, the outer housing should be manually moved in the clockwise direction from the inner rotor hub.
Fig 4: Rotating Intake Camshaft Position Actuator Outer Housing Clockwise
Courtesy of GENERAL MOTORS CORP.
4. Remove the hex key from the oil passage and manually return the outer housing clockwise back to the home position. Ensure the lock pin engages when the outer housing returns to the home position.
5. If the intake camshaft position actuator does not move, the movement is not smooth and even, or the lock pin does not engage in the home position replace the intake camshaft position actuator.
Fig 5: Locating Exhaust Camshaft Position Actuator Inner Rotor Hub & Outer Housing
Courtesy of GENERAL MOTORS CORP.
6. Inspect the exhaust camshaft position actuator to ensure the internal lock pin is engaged and the camshaft position actuator is parked in the home position. Attempt to rotate the inner rotor hub (1) within the outer housing (2).

   If the exhaust camshaft position actuator can be turned in either direction the camshaft position actuator must be replaced.

Fig 6: Locating Exhaust Camshaft Position Actuator External Housing Locking Pin Cover
Courtesy of GENERAL MOTORS CORP.
7. Locate the internal hub oil passage for the locking pin by observing the external housing locking pin cover (1). The oil passage in the hub for the locking pin is inline with the location of the locking pin cover.
Fig 7: Locating Exhaust Camshaft Position Actuator Internal Lock Pin
Courtesy of GENERAL MOTORS CORP.
8. Inspect the exhaust camshaft position actuators for smooth and even movement. The exhaust camshaft position actuator has return springs and the inspection will require additional assistance to perform. Using a pre-bent hex key, smaller than the oil passage, depress the internal lock pin through the oil passage (1) located within the hub of the camshaft position actuator. While viewing the exhaust camshaft position actuator from the front and with the lock pin depressed, the outer housing should be manually moved in the clockwise direction from the inner rotor hub.
Fig 8: Rotating Exhaust Camshaft Position Actuator Outer Housing Clockwise
Courtesy of GENERAL MOTORS CORP.
9. Remove the hex key from the oil passage and allow the outer housing to move counter clockwise back to the home position. Ensure the return springs bring the outer housing back to the home position and the lock pin engages.
10. If the exhaust camshaft position actuator does not move, the movement is not smooth and even, the return springs do not return the outer housing to the home position, or the lock pin does not engage in the home position replace the exhaust camshaft position actuator.

Camshaft Position Actuator Oil Control Valve

Fig 9: Inspecting Camshaft Position Actuator Oil Control Valve For Smooth Spool Valve Movement
Courtesy of GENERAL MOTORS CORP.
NOTE: DO NOT clamp the component in any clamping device such as a vise or gripping tool. Clamping the component can cause external and internal damage that can affect engine and/or component performance.
1. Inspect the camshaft position actuator oil control valves for smooth and even movement of the spool valve within the camshaft position actuator oil control valve body.
Fig 10: Inspecting Camshaft Position Actuator Oil Control Valve For Proper Spool Valve Movement
Courtesy of GENERAL MOTORS CORP.
2. Inspect the camshaft position actuator oil control valves for proper movement of the spool valve. The valve should move a distance (2) of 4.35 mm (0.1713 in). Measure from the underside of the spool valve head. The home position is 2.25 mm (0.0886 in) above (1) the hex and the fully extended position measures 6.60 mm (0.2598 in) above (3) the hex.
Fig 11: Inspecting Camshaft Position Actuator Oil Control Valve For Proper Spool Valve Return
Courtesy of GENERAL MOTORS CORP.
3. Inspect the camshaft position actuator oil control valves for proper return of the spool valve to the home position by the internal spring.