GM Full-Size Trucks 1988-1998 Repair Information

Crankshaft Position (CKP) Sensor

Print

OPERATION



The Crankshaft Position (CKP) sensor is a hall-effect type sensor that monitors crankshaft position and speed. There are four teeth 90¡ apart on the front crankshaft sprocket that induce a pulse in the sensor which is transmitted to the ECM.

TESTING



See Figure 1

  1. Check the sensor wiring, the wiring harness and the terminals for damage and repair as necessary.
  2.  
  3. Disconnect the CKP sensor harness. Connect an Digital Volt Ohm Meter (DVOM) attach the negative lead of the meter to battery ground and the positive lead to CKP harness terminal C. The voltage should be between 4.8-5.2 volts.
  4.  
  5. If not as specified, repair or replace the fuse and/or wiring.
  6.  
  7. Connect an LED test light between the battery positive terminal and CKP terminal B.
  8.  
  9. With the ignition ON and the engine off, verify that the test light illuminates.
  10.  
  11. If not as specified, repair or replace the wiring.
  12.  



Click image to see an enlarged view

Fig. Fig. 1: Crankshaft Position (CKP) sensor wiring diagram-6.5L diesel engine

  1. Turn the ignition OFF and disconnect the test light.
  2.  
  3. Next, connect suitable jumper wires between the CKP sensor and CKP sensor harness. Connect a DVOM to the jumper wire corresponding to CKP terminal A and battery ground.
  4.  
  5. Crank the engine and verify that the voltage is 4 volts or more.
  6.  
  7. If it is not as specified, the CKP sensor may be faulty.
  8.  

REMOVAL & INSTALLATION



See Figure 2

  1. Disconnect the negative battery cable.
  2.  
  3. Detach the sensor harness connector at the sensor.
  4.  
  5. Unfasten the retaining bolt, then remove the sensor from the front cover. Inspect the sensor O-ring for wear, cracks or leakage and replace if necessary.
  6.  

To install:
  1. Lubricate the O-ring with clean engine oil, then place on the sensor. Install the sensor into the front cover.
  2.  
  3. Install the sensor retaining bolt. Tighten the bolt to 17 ft. lbs. (25 Nm).
  4.  
  5. Attach the sensor harness connector.
  6.  
  7. Connect the negative battery cable.
  8.  



Click image to see an enlarged view

Fig. Fig. 2: Location of the CKP sensor mounting-6.5L diesel engine

 
label.common.footer.alt.autozoneLogo