Subject: | Service Information on Resetting Crankshaft Adaptives and Performing Crankshaft
Position Relearn Procedure |
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 be first 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.
New Parts Installed
| Required Procedures
|
Powertrain Control Module (PCM)
| Crankshaft Learning Procedure
|
Crankshaft
| Crankshaft Adaptives Reset Procedure Crankshaft Learning Procedure
|
Crankshaft Position (CKP) Sensor
| Crankshaft Adaptives Rest Procedure Crankshaft Learning Procedure
|
Engine Assembly
| Crankshaft Adaptives Rest Procedure Crankshaft Learning Procedure
|
PCM Installed from One Vehicle to Another
| Crankshaft Adaptives Rest Procedure Crankshaft Learning Procedure
|
Procedure
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.
• | Select Dynamic Display (#3) from the Main Menu |
• | Select View Serial Data (#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.
|