Circuit Description
The camshaft position (CMP) actuator system is comprised of 4 CMP actuator solenoids, 4 oil control valves, and 4 CMP actuators. The engine control module (ECM) sends an electrical signal to the CMP actuator solenoids through the control circuits when a camshaft timing change is desired. The ground circuits of the CMP actuator solenoids are used as a return. The CMP actuator solenoid uses electromagnetic force to pull on the plunger of the oil control valve. The oil control valve will port the pressurized engine oil to either the advancing or retarding chambers of the CMP actuator. The CMP actuator, in turn, changes the CMP relative to the crankshaft position (CKP).
| Camshaft position relative to crankshaft position | Crankshaft position when the intake or exhaust valve begins to open with camshaft actuators in park | Crankshaft position when the intake or exhaust valve begins to open with camshaft actuators at full travel |
|---|---|---|
| Intake Camshafts | 133° ATDC (CMP actuator position is at 0° on scan tool) | 93° ATDC (CMP actuator position is at 40° on scan tool) |
| Exhaust Camshafts | 117° BTDC (CMP actuator position is at 0° on scan tool) | 67° BTDC (CMP actuator position is at 50° on scan tool) |
If the desired CMP does not match the actual CMP for a calibrated amount of time, DTC P0011, P0014, P0021 or P0024 will set.