GM S-Series Pick-ups and SUV's 1994-1999 Repair Guide

Crankshaft Position (CKP) Sensor

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OPERATION



The Crankshaft Position (CKP) sensor provides a signal through the ignition module which the VCM uses as a reference to calculate rpm and crankshaft position.

TESTING



4.3L Engines

See Figures 1 and 2

  1. Disconnect the CKP sensor harness. Connect an LED test light between battery ground and CKP harness terminal A .
  2.  
  3. With the ignition ON and the engine off, verify that the test light illuminates.
  4.  
  5. If not as specified, repair or replace the fuse and/or wiring.
  6.  
  7. Carefully connect the test light between CKP harness terminal A and B . Verify that the test light illuminates.
  8.  



Click image to see an enlarged view

Fig. Fig. 1: Typical Crankshaft Position (CKP) sensor wiring diagram-late model 4.3L engines (wire color, terminal identification/location may vary on certain models)



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Fig. Fig. 2: Typical Crankshaft Position (CKP) sensor wiring diagram-late model 4.3L engines (wire color, terminal identification/location may vary on certain models)

  1. If not as specified, repair the CKP harness ground circuit (terminal B ).
  2.  
  3. Turn the ignition OFF and disconnect the test light.
  4.  
  5. Next, connect suitable jumper wires between the CKP sensor and CKP sensor harness. Connect a duty cycle meter to the jumper wire corresponding to CKP terminal C and battery ground.
  6.  
  7. Crank the engine and verify that the duty cycle signal is between 40-60%.
  8.  
  9. If it is not as specified, the CKP sensor may be faulty.
  10.  
  11. Next, connect a AC volt meter to the jumper wire corresponding to CKP terminal C and battery ground.
  12.  
  13. Crank the engine and verify that the AC voltage signal is at least 10.0 volts.
  14.  
  15. If not as specified the CKP sensor may be faulty.
  16.  

2.2L Engine

See Figures and 3 and 4

  1. Turn the ignition key OFF .
  2.  
  3. Unplug the sensor electrical harness and check the terminals for corrosion and damage.
  4.  
  5. Check the sensor wiring harness wires for continuity and repair as necessary.
  6.  
  7. Attach the sensor harness making sure it is firmly engaged.
  8.  
  9. Using a Digital Volt Ohm Meter (DVOM) set on the DC scale, backprobe the sensor signal terminal (terminal A) with the positive lead of the meter and backprobe the sensor ground terminal (terminal B) with the negative lead of the meter.
  10.  
  11. Have an assistant crank the engine and observe the meter.
  12.  
  13. You should have approximately a 5 volt reference signal pulse. If not the sensor may be defective.
  14.  



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



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Fig. Fig. 4: Attach suitable jumper wires between the CKP sensor and CKP sensor harness. A DC volt meter can then be attached to the necessary terminals to test the sensor as the engine is being cranked

REMOVAL & INSTALLATION



See Figures 5, 6, 7, 8 and 9



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Fig. Fig. 5: View of the Crankshaft Position Sensor (CKP) location-1996-99 4.3L engines



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Fig. Fig. 6: View of the Crankshaft Position Sensor (CKP) location-1996-99 2.2L engines



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Fig. Fig. 7: The Crankshaft Position (CKP) sensor is located on the passenger side of the engine block below the coil pack and is accessible when the vehicle is raised and supported with jackstands-2.2L engines

  1. Disconnect the negative battery cable.
  2.  
  3. Raise the vehicle and support it with jackstands.
  4.  
  5. If equipped on 4.3L engines, remove the steering linkage shield to access the sensor.
  6.  
  7. Unplug the sensor harness connector at the sensor.
  8.  
  9. Unfasten the retaining bolt, then remove the sensor from the front cover on 4.3L engines, or from below the coil pack on 2.2L engines. Inspect the sensor O-ring for wear, cracks or leakage and replace if necessary.
  10.  



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Fig. Fig. 8: Unfasten the Crankshaft Position (CKP) sensor retaining bolt-2.2L engine shown



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Fig. Fig. 9: After the Crankshaft Position (CKP) sensor retaining bolt has been removed, grasp the sensor and pull it from its bore in the engine block using a slight twisting motion-2.2L engine shown

To install:
  1. Lubricate the O-ring with clean engine oil, then place it on the sensor. Install the sensor into the front cover (4.3L) or below the coil pack (2.2L).
  2.  
  3. Install the sensor and tighten the retaining bolt.
  4.  
  5. Attach the sensor harness connector.
  6.  
  7. If removed, install the steering linkage shield.
  8.  
  9. Lower the vehicle.
  10.  
  11. Connect the negative battery cable.
  12.  

 
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