GM Cadillac Deville_Fleetwood_ELD_Seville 1990-1998

Crankshaft Position Sensor



The Crankshaft Position (CKP) sensor works in conjunction with a 58 tooth reluctor wheel on the crankshaft. The PCM pulls up the CKP sensor signal circuit to 12 volts and monitors this voltage. As each 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 teeth are 6 degrees apart. Having only 58 teeth leaves a 12 degree span that I s uncut. This creates a signature pattern that enables the PCM to determine crankshaft position. The PCM can determine which two cylinders are approaching top dead center based on the signal is used to determine which of the two cylinders I on a firing stroke. The PCM can then properly synchronize the ignition system, Fuel injectors and knock control. This sensor is also used to detect misfire.

The PCM also monitors the CKP sensor system for malfunctions.


Diagnostic Aids -check for:

Incorrect harness routing.
An intermittent may be caused by a poor connection, rubbed through wire insulation or a wire broken inside the insulation.
Check for a poor connection or damaged harness: Inspect the PCM harness connectors for backed out terminals, improper mating, broken locks, improperly formed or damaged terminals, poor terminal to wire connections and damaged harnesses.
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.
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.


  1. Disconnect the wiring harness from the Crankshaft Position (CKP) sensor.
  3. Remove the fastening bolt for the CKP sensor.
  5. Remove the CKP sensor and the O-ring seal from the engine block.

To install:

  1. Thoroughly clean the mating surfaces of the CKP sensor and the engine bock.
  3. Install the CKP sensor with a new O-ring seal, into the engine block.
  5. Install he fastening bolt for the CKP sensor
  7. Attach the wiring harness to the CKP sensor. Be sure to route the cable correctly

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Fig. The location of the Crankshaft Position Sensor (CKP)-3.0L engine

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Fig. Location of the CKP sensor connector-3.0L engine