Originally posted by 97LT1Z28
1. Set the parking brake and make sure you are in Park or have the shifter in neutral.
2. Block the wheels.
3. Close the hood.
4. Start the motor and allow the engine coolant temperature to reach at least 158°F (70°C). I always let it get just a little above that.
5. Toggle the key off then back to on.
6. Make sure you still have a "No Codes Present" status.
7. Select and enable the CKP Variation Learn procedure with the scanner. It is usually under Codes and Engine data, Engine Data 1, then Procedures.
8. Start the engine again.
9. Press and hold the brake pedal. You must keep the brake pedal engaged throughout the entire process until the scanner indicates that the CKP variation has been learned.
10. The scanner will now tell you to rev the motor until fuel cutoff is reached (usually 4,050 RPM but can vary a little). So press the loud pedal steadily but slowly until the CKP System Variation Learn fuel cutoff is reached at 4,050 RPM. Listen closely you will hear 2 consecutive and quick fuel cutoffs. As soon as you hear the second one, let off the loud pedal completely.
The crankshaft position system variation compensating values are learned when the RPM decreases back to idle. If the scanner still says "Waiting for Full Throttle" or if the procedure terminates, you likely have not made sure that all the above criteria are met.
BTW, DTC P1336 will not clear from memory automatically or if the learn procedure was unsuccessful. If it was succesful, then you must clear the codes again manually.
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