GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Chevrolet 🢒 2001 🢒 Impala 🢒 Engine 🢒 Engine Controls - 3.4L 🢒 Crankshaft Position System Variation Learn

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.

Important: :  The scan tool Crankshaft Position System Variation Learn function will be inhibited if the engine coolant temperature is less than 70°C (158°F). Allow the engine to warm to at least 70°C (158°F) 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 set. Refer to the 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 diagnose the system or the sensor.

   •  DTC P0336
   •  DTC P0341
   •  DTC P1374
The scan tool Crankshaft Position System Variation Learn function will not be enabled until the engine coolant temperature reaches 70° C (158° F).

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 during the Crankshaft Position System Variation Learn Procedure in order to store the crankshaft position system variation compensating values and complete the procedure.

Important: :  Block the drive wheels when performing the Crankshaft Position System Variation Learning Procedure in order to prevent personal injury. Set the vehicle parking brake when instructed by the scan tool. Quickly increase the accelerator pedal position until reaching wide open throttle and hold. During the learn procedure the PCM will automatically control the injector operation. When the RPM has reached a certain level, the PCM will stop the fuel injectors from pulsing, until the learn procedure is finished. When the PCM has learned the crankshaft variation, the fuel injectors will return to normal operation and the engine will begin to accelerate again. Release the throttle when the engine reaches the second fuel cut off. Leaving the throttle open during the fuel cut off learn procedure will allow the engine to decelerate at an even rate.

  1. Block the drive wheels.
  2. Ensure the hood is closed.
  3. Start the engine and allow the engine coolant temperature to reach at least 70°C (158°F).
  4. Turn OFF the ignition.
  5. Select and enable the Crankshaft Position System Variation Learn Procedure with the scan tool.
  6. Set the parking brake when instructed by the scan tool.
  7. Start the vehicle.
  8. Apply and hold the service brake pedal firmly.
  9. Ensure the transaxle is in Park.
  10. Steadily increase the accelerator pedal until the fuel cutoff is reached at 5150 RPM and hold. Release the accelerator pedal after the second fuel cutoff has been reached.
  11. The crankshaft position system variation compensating values are learned when the RPM decreases back to idle.
  12. Observe the DTC status for DTC P1336.
  13. 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.