GMC Camshaft Position (CMP) Sensor replacing?

The camshaft position sensor is a magnetic or hall effect sensor. It sends a signal to the computer relaying information about shaft speed, position and acceleration or deceleration. This information determines when the fuel/air mixture needs to be ignited and how much mixture is needed for the engine.

See all 3 sections of camshaft sensor:----
OPERATION
TESTING
REMOVAL & INSTALLATION.

OPERATION

See Figure 1

The VCM uses the camshaft signal to determine the position of the No. 1 cylinder piston during its power stroke. The signal is used by the VCM to calculate fuel injection mode of operation. If the cam signal is lost while the engine is running, the fuel injection system will shift to a calculated fuel injected mode based on the last fuel injection pulse, and the engine will continue to run.

Fig. Fig. 1: Camshaft Position (CMP) sensor location-1996-99 2.2L engines

TESTING

See Figures 2, 3, 4 and 5

Fig. Fig. 2: Typical Camshaft Position (CMP) wiring schematic-4.3L engines (wire color, terminal identification/location may vary on certain models)

1. Remove the ECM fuse to prevent the engine from starting. Removal of the ECM fuse does not disable the sensor power supply and allows testing of this sensor safely.
2. Disconnect the CMP sensor wiring harness and attach suitable jumper wires between the CMP sensor and CMP sensor harness. Connect a DC volt meter to the jumper wires corresponding to CMP IGN or PWR terminal and sensor ground.
3. With the ignition ON and the engine off, verify that the voltage is approximately battery voltage. The supply voltage should be slightly less than battery voltage.
4. If not as specified, repair or replace the fuse and/or wiring.
5. Connect a DC volt meter to the jumper wires corresponding to CMP signal terminal and sensor ground.
6. Place a socket and breaker bar or the crankshaft pulley bolt and rotate the engine slowly by hand. Observe the volt meter and verify that the voltage signal varies from approximately zero volts to slightly less than supply voltage. The voltage will switch on when the target passes the sensor and will show little or no voltage when the target is past the sensor.
7. If it is not as specified, the CMP sensor may be faulty.

Fig. Fig. 3: Common Camshaft Position (CMP) sensor wiring schematic-2.2L engines (wire color, terminal identification/location may vary on certain models)

Fig. Fig. 4: Attach suitable jumper wires between the CMP sensor and CMP sensor harness. Connect a DC volt meter to the jumper wires corresponding to IGN and sensor ground terminals and note the reading

Fig. Fig. 5: Connect the volt meter to the jumper wire corresponding to signal and sensor ground terminals, rotate the engine and observe the volt meter and verify that the voltage signal varies from approximately zero volts to slightly less than supply voltage

REMOVAL & INSTALLATION

2.2L Engines

See Figures 6 and 7

1. Disconnect the negative battery cable.
2. Raise the vehicle and support it with safety stands.
3. Remove the right hand tire assembly.
4. Unplug the sensor harness connector at the sensor.
5. Unfasten the retaining bolt, then remove the sensor from the camshaft housing.

Fig. Fig. 6: The Camshaft Position (CMP) sensor is located on the passenger side of the engine and is accessible after removing the right front tire-2.2L engine

Fig. Fig. 7: Unplug CMP sensor electrical connection and unfasten the sensor retainer, then remove the sensor from its bore in the block-2.2L engine

To install:

6. Place the sensor into position.
7. Install the CMP sensor retaining bolt, then tighten to 88 inch lbs. (10 Nm).
8. Attach the sensor harness connector.
9. Istall the tire assembly and lower the vehicle.
10. Connect the negative battery cable.

4.3L Engines

Models equipped with a distributor ignition (DI) or high voltage switch (HVS) system

The Camshaft Position (CMP) sensor is located in the distributor assembly.

1. Disconnect the negative battery cable.
2. Unplug the electrical connection from the CMP sensor.
3. Remove the distributor cap and rotor.
4. Unfasten the CMP sensor retainer(s).

If equipped, the square cut hole in the vane wheel must be aligned with the sensor in order for the sensor to be removed.

5. Remove the sensor from the distributor.

To install:

6. If equipped, line up the square cut hole in the vane wheel with the sensor and install the sensor.
7. Install the sensor and its retainers. Do not overtighten the retainers as the plastic base may strip.
8. Install the rotor and cap, then attach all necessary electrical connections.
9. Connect the negative battery cable.

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This details will help you.Thanks.

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