Crank Sensor Relearn?

I'm going to have my Crank Sensor done in about two weeks. I was told by the GM dealer that I had to bring the car back in for a re-learn after the Sensor is installed. My mechanic who is doing the work said the computer will set off the SES light and then go off after a few cycles i.e. relearning itself. Any one know what the FSM says or from experience?

what year is your car? (add it to your signature).

later PCMs need a CASE learn (Crank Angle Sensor Esomthing). I had to do this after swapping motors. You should also do it after swapping Crank or Cam sensors. It is an automated procedure that takes about 5 seconds. It is not something you can do at home without a computer/programmer that can put the PCM into CASE learn mode.

It teaches the PCM about the precision of the timing chain and the cam position sensor relative to the crank position sensor for more accurate ignition timing control.

It is debatable whether it's necessary if the PCM hasn't tripped an error code for it, but I think it's a good practice to do after anything relative to the cam or crank sensors have changed.

98. I cant seem to get my sig to show up!

https://rivperformance.editboard.com/faq

Yep, Mine was turned off! Thanks!

Samuel, the PCM might tolerate the swap without lighting the SES light, and I think that other scanners besides the GM dealers' unit can access the learn procedure... If so, the manual says this:

Important:
Begin the crankshaft position system variation learn procedure with the ignition switch OFF. Do not turn ON the ignition switch or start the vehicle unless instructed to do so by the scan tool.

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. Clear DTCs before attempting to perform the crankshaft position system variation learn procedure. If any DTCs reset, the DTCs must be diagnosed and repaired before the crankshaft position system variation learn procedure can be sucessfully completed.

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 18X reference circuit.............

# Start the engine and allow engine coolant temperature to reach at least 70°C (158°F).
# Turn OFF the ignition switch, THEN
# Select and enable the crankshaft position variation learn procedure with the scan tool.
# Start the vehicle
# Ensure that the transaxle is in Park.
# Apply and hold the service brake pedal firmly.
# Increase accelerator pedal position until CKP system variation learn fuel cutoff is reached. CKP system variation learn fuel cutoff is reached at 5150 RPM. Immediately release the accelerator pedal when fuel cutoff is reached.
# The crankshaft position system variation compensating values are learned when RPM decreases back to idle.
# Observe DTC status for DTC P1336.
# 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, check for other DTCs. If no DTCs other than P1336 are set, repeat the crankshaft position system variation learn procedure as necessary.

.

Thanks Much!

If bothering with the crank relearn, definitely look to see if someone nearby has a DHP or HPT software before going to the dealer and spending $$$. unless of course, you have a hookup at the dealer