GM Cadillac Deville_Fleetwood_ELD_Seville 1990-1998

Camshaft Position Sensor

Print

OPERATION



The Camshaft Position (CMP) sensor works in conjunction with a single tooth reluctor wheel on the Bank 2 intake camshaft. The PCM pulls up the CMP sensor signal circuit to 12 volts and monitors this voltage. As the reluctor wheel tooth rotates past the sensor, the sensor's internal circuitry pulls the signal circuit to ground, creating a square wave signal used by the PCM. The reluctor wheel tooth covers 180 degrees of the camshaft circumference. This causes the CMP signal voltage to transition once per crankshaft revolution. This signal, when combined with the CKP sensor signal, enables the PCM to determine exactly which cylinder is on a firing strike. The PCM can then properly synchronize the ignition system, fuel injectors and knock control. Note that as long as the CKP signal is available, the engine can start even if there is no CMP sensor signal. The PCM will default to non-sequential fuel injector operation.

TESTING



The PCM also monitors the CKP sensor system for malfunctions.

For any test that requires probing the PCM harness connector or a component harness connector, use the connector test adapter kit (J 35616-A). Using this kit will prevent damage to the harness connector terminals.

  1. Check for the following conditions:
    1. Poor connections at the PCM or at the component.-Inspect the harness connectors for backed out terminals, improper mating, broken locks, improperly formed or damaged terminals, and poor terminal to wire connection
    2.  
    3. Misrouted harness.-Inspect the harness to ensure that it is not routed too close to high voltage wires such as spark plug leads, or too close to high current devices such as the alternator, motors, solenoids etc.
    4.  
    5. Damaged harness.-Inspect the wiring harness for damage. If the harness appears to be OK, observe the scan tool while moving related connectors and wiring harnesses. A change in the display may help to locate the fault.
    6.  
    7. If the sensor signal is only affected when the harness is moved at a component, and there is no problem with the harness or connections, the component may be faulty.
    8.  

  2.  
  3. Check the sensor for proper installation.-A sensor that is loose or not fully seated (causing an excessive air gap between the sensor and the reluctor wheel) may cause a DTC to set.
  4.  

REMOVAL & INSTALLATION



  1. Disconnect the wiring harness from the Camshaft Position (CMP) Sensor.]
  2.  
  3. Remove the A/C Low Pressure ling bracket.
  4.  
  5. Remove the fastening bolt for the CMP sensor.
  6.  
  7. Remove the CMP sensor and the O-ring seal from the camshaft cover.
  8.  

To install:

  1. Thoroughly clean the mating surfaces of the CMP sensor and the camshaft cover.
  2.  
  3. Install the CMP sensor with a new O ring seal, into the camshaft cover.
  4.  
  5. Install the fastening bolt for the CMP sensor.
  6.  
  7. Install the A/C Low Pressure line bracket.
  8.  
  9. Attach the wiring harness to the CMP sensor. Be sure to route the cable correctly.
  10.  



Click image to see an enlarged view

Fig. Location of the Camshaft Position (CMP ) Sensor-3.0L engine

 
label.common.footer.alt.autozoneLogo