Crankshaft Position System Variation Learn (LF1, LFW)
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Crankshaft Position System Variation Learn (LF1, LFW)
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Note
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The Crankshaft Position System Variation Learn procedure is also required when the following service procedures have been performed, regardless of whether DTC P0315 is set:
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An engine replacement
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A engine control module (ECM) replacement
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A crankshaft balancer replacement
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A crankshaft replacement
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A crankshaft position sensor replacement
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Any engine repairs which disturb the crankshaft to crankshaft position sensor relationship.
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Note
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The ECM monitors certain component signals to determine if all the conditions are met to continue with the crankshaft position System Variation Learn Procedure. The scan tool only displays the condition that inhibits the procedure. The scan tool displays the signals of the following components:
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Crankshaft position sensors activity-If there is a crankshaft position sensor condition, refer to the applicable DTC that set.
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Camshaft position sensor signal activity-If there is a camshaft position sensor signal condition, refer to the applicable DTC that set.
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Engine coolant temperature (ECT)-If the engine coolant temperature is not warm enough, idle the engine until the engine coolant temperature reaches the correct temperature.
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3.
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With a scan tool, select the Crankshaft Position System Variation Learn Procedure and perform the following:
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3.3.
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DO NOT apply brake pedal.
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3.4.
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Cycle ignition from OFF to ON.
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3.5.
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Apply and hold brake pedal for the duration of the procedure.
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3.6.
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Start and idle engine.
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3.7.
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Turn the air conditioning (A/C) OFF.
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3.8.
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The vehicle must remain in Park or Neutral.
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3.9.
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Note
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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.
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Accelerate to wide open throttle (WOT) and release when the fuel cut-off occurs.
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4.
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The scan tool displays Learn Status: Learned this Ignition. If the scan tool indicates that DTC P0315 ran and passed, the crankshaft position variation learn procedure is complete. If the scan tool indicates DTC P0315 failed or did not run, or another DTC is present, refer to
Diagnostic Trouble Code (DTC) List - Vehicle
and perform the appropriate diagnostic procedure.
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5.
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Once the learn procedure has successfully completed, and in order to store the crankshaft position system variation values in the ECM, turn OFF the ignition and verify all vehicle systems are OFF. This may take up to 2 minutes.
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