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Home >> Buick >> 2003 >> Century Custom >> Repair and Diagnosis >> Engine Performance >> System >> Engine Controls Self-Diagnostics - 3.1L Engine >> Programming >> CKP System Variation Learn Procedure
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CKP System Variation Learn Procedure

NOTE: For additional diagnostic information, refer to DTC P1336: CRANKSHAFT POSITION SYSTEM VARIATION NOT LEARNED  under DIAGNOSTIC TESTS.
  1. Connect scan tool to DLC.
  2. Monitor the Powertrain Control Module (PCM) for DTCs. If other DTCs are set, except DTCs P1336, refer to DIAGNOSTIC TROUBLE CODE DEFINITIONS  for the applicable DTC that set.
  3. Using a scan tool, select the CRANKSHAFT POSITION VARIATION LEARN procedure.
  4. Observe the fuel cut-off specifications for the engine that you are performing the learn procedure on.
  5. The scan tool instructs you to perform the following:
    • Block the drive wheels.
    • Apply the vehicles parking brake.
    • Cycle the ignition switch from OFF to RUN position.
    • Apply and hold the brake pedal.
    • Start and idle the engine.
    • Place the vehicle's automatic transmission in Park, or the manual transmission in Neutral.
    • The scan tool monitors certain component signals to determine if all the conditions are met to continue with the procedure. The scan tool only displays the condition that inhibits the procedure. The scan tool monitors the following components:
      1. CKP sensors activity  - If there is a CKP sensor condition, refer to the applicable DTC that set.
      2. Camshaft Position Sensor activity  - If there is a Camshaft Position Sensor (CMP) sensor condition, refer to the applicable DTC that set.
      3. Engine Coolant Temperature  - If the Engine Coolant Temperature (ECT) is not warm enough, idle the engine until the ECT reaches the correct temperature.
  6. Enable the crankshaft position system variation learn procedure using the scan tool.
    7. NOTE: While the learn procedure is in progress, release the throttle immediately when the engine starts to decelerate. The engine control is returned to the operator and the engine responds to throttle position after the learn procedure is complete.
  7. Slowly increase the engine speed to the RPM that you observed.
  8. Immediately release the throttle when fuel cut-off is reached.
  9. The scan tool displays LEARN STATUS: LEARNED THIS IGNITION. If the scan tool does NOT display this message and no additional DTCs set, go to appropriate article in ENGINES. If a DTC set, refer to Diagnostic Trouble Code (DTC) List for the applicable DTC that set. If any other DTCs set, go to DIAGNOSTIC TROUBLE CODE DEFINITIONS  for the applicable DTC that set.
  10. Turn ignition switch to OFF position for 30 seconds after the learn procedure is completed successfully.
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