Description & Operation
The Camshaft Position Sensor (CMP) sensor contains a hall effect device referred to as a sync signal generator. A rotating target wheel (tone wheel) for the CMP is located at the front of the camshaft for the right cylinder head. This sync signal generator detects notches located on a tone wheel. As the tone wheel rotates, the notches pass through the sync signal generator. The signal from the CMP sensor is used in conjunction with the Crankshaft Position Sensor (CKP) to differentiate between fuel injection and spark events. It is also used to synchronize the fuel injectors with their respective cylinders.
When the leading edge of the target wheel notch enters the tip of the CMP, the interruption of magnetic field causes the voltage to switch high, resulting in a sync signal of approximately 5 volts. When the trailing edge of the target wheel notch leaves the tip of the CMP, the change of the magnetic field causes the sync signal voltage to switch to 0 volts.
Removal & Installation
- Raise and safely support the vehicle.
- Disconnect the CMP electrical connector.
- Remove the CMP sensor mounting bolts.
- Carefully twist the sensor from the cylinder.
- Check the condition of the sensor O-ring.
- Clean out the machined hole in the cylinder head.
- Apply a small amount of clean engine oil to the sensor O-ring.
- Install the CMP sensor into the cylinder head with a slight rocking and twisting action.
- Install the mounting bolt and tighten to 106 inch lbs. (12 Nm).
- Connect the electrical connector.
- Lower the vehicle.
- Using a diagnostic scan tool, check for the presence of any Diagnostic Trouble Codes (DTCs). Record and address these codes as necessary.
Turn the ignition
and disconnect the Camshaft Position (CMP) Sensor harness connector.
NOTEIf any of the test results fall outside of the specification, stop and repair the affected component.
- With the Ignition on, and engine not running, measure the voltage on the (F856) 5-volt Supply circuit in the CMP Sensor harness connector. Is the voltage between 4.5 and 5.2 volts-
- If it is, measure the voltage on the (K44) CMP Signal circuit in the CMP Sensor harness connector. The voltage should be between 4.5 and 5.0 volts.
If it is, turn the ignition off and disconnect the C2 ECM harness connector.
CAUTIONDo not probe the ECM harness connectors. Probing the ECM harness connectors will damage the ECM terminals resulting in poor terminal to pin connection. Install Miller Special Tool No. 8815 to perform diagnosis.
- Measure the resistance of the (K900) Sensor ground circuit from the CMP Sensor harness connector to the appropriate terminal of special tool No. 8815. If the resistance is below 5.0 ohms, proceed to the next step, otherwise repair the open ground in the K900 sensor.
Measure the resistance between the (K44) CMP Signal circuit and the (F856) 5-volt Supply circuit in the CMP Sensor harness connector. If the resistance is below 5.0 ohms, repair the short between the (K44) CMP Signal circuit and the (F856) 5-volt Supply circuit.
NOTEInspect the Camshaft sprocket for damage per the Service Information. If a problem is found repair as necessary.