Escalade, Suburban, Tahoe, Yukon, Denali, DenaliXL, YukonXL 1999-2005

Crankshaft Position Sensor

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Crankshaft Position System Variation Learn Procedure



The crankshaft position system variation compensating values are stored in the PCM non-volatile memory after a learn procedure has been performed. If the actual crankshaft position system variation is not within the crankshaft position system variation compensating values stored in the PCM, DTC P0300 may set. Refer to Diagnostic Aids for DTC P0300. The Crankshaft Position System Variation Learn Procedure should be performed if any of the following conditions are true:



DTC P1336 is set.
 
The PCM has been replaced.
 
The engine has been replaced.
 
The crankshaft has been replaced.
 
The crankshaft harmonic balancer has been replaced.
 
The crankshaft position sensor has been replaced.
 


CAUTION
The scan tool crankshaft position system variation learn function will be inhibited if engine coolant temperature is less than 70C (158F). Allow the engine to warm to at least 70C (158F) before attempting the crankshaft position system variation learn procedure. The scan tool crankshaft position system variation learn function will be inhibited if any Powertrain DTCs other than DTC P1336 are set before or during the crankshaft position system variation learn procedure. Diagnose and repair any DTCs if set. Refer to applicable DTCs. The crankshaft position system variation learn function will be inhibited if the PCM detects a malfunction involving the camshaft position signal circuit, the 3X reference circuit, or the 24X reference circuit. If a malfunction has been indicated, refer to the following list to diagnoses the system or sensor.



DTC P0336 Crankshaft Position (CKP) Sensor Circuit.
 
DTC P0341 Camshaft Position (CMP) Sensor Performance.
 
DTC P1374 Crankshaft Position (CKP) High to Low Resolution Frequency Correlation.
 

The scan tool crankshaft position system variation learn function will not be enabled until engine coolant temperature reaches 158F (70C). Selecting the crankshaft position system variation learn procedure on the scan tool will command the PCM to enable CKP system variation learn fuel cutoff and allow the crankshaft position system variation compensating values to be stored in the PCM. The PCM must detect an engine speed of 5150 RPM (CKP system variation learn fuel cutoff) during the crankshaft position system variation learn procedure to store the crankshaft position system variation compensating values and complete the procedure.


CAUTION
Set the vehicle parking brake and block the drive wheels when performing the Crankshaft Position System Variation Learning Procedure in order to prevent personal injury. Release the throttle when the engine reaches the second fuel cut off. Leaving the throttle open during the fuel cut off will allow the engine to decel at an even rate. Once the learn procedure is completed, the PCM will return the engine control to the operator and the engine will respond to the throttle position.

  1. Set the parking brake.
  2.  
  3. Block the drive wheels.
  4.  
  5. Ensure the hood is closed.
  6.  
  7. Start the engine and allow engine coolant temperature to reach at least 70C (158F).
  8.  
  9. Turn off the ignition switch.
  10.  
  11. Select and enable the crankshaft position variation learn procedure with the scan tool.
  12.  
  13. Start the vehicle.
  14.  
  15. Apply and hold the service brake pedal firmly.
  16.  
  17. Ensure the transaxle is in park.
  18.  
  19. Increase accelerator pedal position and hold until the fuel cutoff is reached at 5150 RPM. Release the accelerator pedal after the second fuel cutoff has been reached.
  20.  
  21. The crankshaft position system variation compensating values are learned when the RPM decreases back to idle. If the procedure terminates.
  22.  
  23. Observe DTC status for DTC P1336.
  24.  
  25. If the scan tool indicates that DTC P1336 ran and passed, the crankshaft position system variation learn procedure is complete. If the scan tool indicates DTC P1336 failed or not run, determine if other DTCs have set. If DTCs other than P1336 are not set, repeat the crankshaft position system variation learn procedure as necessary.
  26.  

Operation



The Crankshaft Position (CKP) sensor senses the crank angle (piston position) of each cylinder and converts it into a pulse signal. The PCM receives this signal and then computes the engine speed and controls the fuel injector timing and ignition timing based on this input.

Removal & Installation




NOTE
Use of a scan tool is required to complete this procedure. Anytime the CKP sensor is replaced, the variation learn procedure must be performed.

4.8L, 5.3L, 6.0L And 6.2L Engines
  1. Raise and safely support the vehicle.
  2.  
  3. Remove the starter.
  4.  
  5. Working through the wheel well opening, unplug the harness connector from the sensor.
  6.  
  7. Clean the area around the sensor to prevent debris from entering the engine.
  8.  
  9. Remove the bolt securing the sensor, then remove it from the engine.
  10.  
  11. Installation is the reverse of removal. Lubricate a new O-ring with clean engine oil. Tighten the bolt to 18 ft. lbs. (25 Nm). Connect the scan tool to the vehicle and perform the CKP sensor variation learn procedure.

    Click image to see an enlarged view

    Fig. CKP sensor mounting-4.8L, 5.3L, 6.0L and 6.2L engines

  12.  

8.1L Engines
  1. Raise and safely support the vehicle.
  2.  
  3. Remove the skid plate, if equipped. Remove any components necessary to ease access to the sensor (ignition coils, etc).
  4.  
  5. Unplug the harness connector from the sensor.
  6.  
  7. Remove the bolt securing the sensor, then remove it from the engine.
  8.  
  9. Installation is the reverse of removal. Lubricate a new O-ring with clean engine oil. Tighten the bolt to 106 inch lbs. (12 Nm). Connect the scan tool to the vehicle and perform the CKP sensor variation learn procedure.
  10.  

Testing



  1. Inspect the CKP sensor for correct installation. Remove the CKP sensor from the engine and inspect the sensor O-ring for damage. If the sensor is loose, incorrectly installed, or damaged, replace the CKP sensor.
  2.  
  3. Engage the CKP sensor harness connector to the CKP sensor.
  4.  
  5. Connect the scan tool to the diagnostic connector.
  6.  
  7. With the ignition ON, engine OFF observe the CKP Active counter parameter on the scan tool.
  8.  
  9. Pass a flat steel object across the tip of the sensor repeatedly. The CKP Active counter parameter should increment with each pass of the steel object.
  10.  
  11. If the parameter does not increment, replace the CKP sensor.
  12.  

 
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