ECM - Crankshaft Learned On Replacement PCMs Set to No
BULLETIN NO.: 96-T-39ISSUE DATE: June, 1996
GROUP/SEQ. NO.: Engine-10
CORPORATION NO.: 686003
SUBJECT:
Service Information on Resetting Crankshaft Adaptives and Performing Crankshaft Position Relearn Procedure
MODELS AFFECTED:
1996 Saturns
PURPOSE:
Service powertrain control modules (PCMs) are shipped with the "Crankshaft Learned" parameter set to "NO." This will cause the Service (Wrench) telltale to flash after installation of the PCM into the vehicle. The Service (Wrench) telltale flashes to remind the service technician to perform the "Crankshaft Learning Procedure" found in the "1996 Revised Powertrain Controls Service Manual" and this bulletin. After performing the "Crankshaft Learning Procedure," the PCM will set the "Crankshaft Learned" parameter to "YES" and the Service (Wrench) telltale will stop flashing.
When a crankshaft position (CKP) sensor, crankshaft or engine assembly have been replaced, or when a PCM is removed from one vehicle and installed in another vehicle, or when diagnostic procedures require crankshaft re-learning, the "Crankshaft Adaptives Reset Procedure"in this bulletin must first be performed. The "Crankshaft Adaptives Reset Procedure" resets the PCM "Crankshaft Learned" parameter to "NO," causing the Service (Wrench) telltale to flash. The "Crankshaft Learned" parameter must be set to "NO," before the "Crankshaft Learning Procedure" can be performed.
PROCEDURES
Crankshaft Adaptives Reset Procedure (Using the Service Stall System):
IMPORTANT:
This procedure is required prior to performing the "Crankshaft Learning Procedure" unless a new PCM has been installed.
^ Key On, Engine Off
^ Identify the Vehicle
^ Select Dynamic Display (# 3) from the Main Menu
^ Select View Serial Data (# 1)
^ Select PCM/EC (# 1)
^ Select Vehicle ID Table (# 2)
^ Press F7 to select Reset Adaptives (bottom of screen)
^ Select Reset Crankshaft Adaptives (# 2)
^ Turn the ignition key Off for ten seconds
Crankshaft Learning Procedure:
IMPORTANT:
This procedure is required when a PCM is replaced and also after "Crankshaft Adaptives Reset Procedure" has been performed.
IMPORTANT:
Any misfire diagnostic trouble code (DTC) or misfire condition must be cleared before proceeding with the crank learning procedure. The PCM will abort the learning procedure if any misfire is detected.
^ Start the engine and allow it to idle
^ The Service (Wrench) telltale will begin to flash
^ Raise engine speed to between 3000 and 4000 RPM
^ Hold engine speed between 3000 and 4000 RPM until the Service (Wrench) telltale goes out (approximately 10 seconds)
^ If the Service (Wrench) telltale has not turned Off after a few seconds, misfire is still present and must be diagnosed before attempting the crankshaft learning procedure again.
IMPORTANT:
After resetting crankshaft adaptives, the misfire table can be selected on the service stall system, in order to view the status of the crank learned parameter. The crank learned parameter will switch from NO to YES if the crank has been learned successfully.