June 30, 2008
Part Two of a Two-Part Series
Last month in AW 55-50 Differences between Manufacturers - Part 1 we explained the variety of operating modes the different manufacturers use to control AW 55-50 units in their vehicles. Knowing the modes and when they are activated is the first step in making an accurate diagnosis. A symptom reported by a customer may be normal, intended operation for one brand of vehicle and a legitimate problem in another. As part of your diagnosis, you should also be aware that every manufacturer has at least one transmission control module (TCM) reflash or replacement bulletin to address various transmission concerns.
If there is a problem and you complete a repair, the next challenge is to understand and correctly use the different relearn procedures. No matter which type of vehicle you are working on, it is imperative that the adaptive relearn procedures be performed to avoid shift feel and engagement feel problems.
Performing the adaptive learn procedure on a Volvo requires a VADIS (Volvo factory scanner) to put the TCM in the "Control Module Adaptation" mode. Some vehicles do not have this function available and will need to have the TCM software reflashed so that the control module adaptation mode will work. The TCM will not go into adaptation mode unless the transmission oil temperature is between 150°F and 230°F. The TCM will not adapt in Geartronic or Winter Mode. While the TCM is in the Adaptation Mode, the orange triangle in the center of the instrument cluster will flash when the adaptation has been completed for a particular shift.
To Adapt the Up Shifts:
To Adapt the Down Shifts:
To Adapt the Garage Shifts:
To Adapt the Neutral Control Function:
Note: Not every Volvo has the Neutral Control Function.
Once all of the adapts have been learned, turn off the ignition and the TCM will exit the adaptation mode.
For more precise information see Volvo Tech Bulletin # 43-27 for 2001 S60,V70,V70VC, and XC90 2.5T.For all other Volvos using the AW55-50 transmission, see Volvo Tech Bulletin # 43-20.
To clear the shift adapts, a Consult Scan Tool (Nissan factory scanner) must be used. The EEPROM in the TCM is erased and reset to the default settings during a process that Nissan refers to as "TCM Initialization". During this initialization the up shift, down shift, engagement, and torque reduction adapts are relearned.
At this time, no aftermarket scan tool is capable of performing the TCM Initialization, nor is there a manual reset procedure.
Nissan Service Bulletin # NTB05-026
TCM Reprogramming Needed When Replacing A 5-Speed A/T. This bulletin applies to 2004-05 Maxima and 2005 Altima with 5- speed automatic transaxle.
Resetting the Shift Adapts
The Chevrolet Equinox and the Pontiac Torrent require a scan tool to initiate the relearn procedure once the transmission oil temperature reaches 150°F. Clear the old shift adapts and initiate the relearn procedure with the Tech 2 or equivalent scan tool, then the adapts can be relearned as follows:
The Tech 2 will work on Saturn vehicles too. There is a manual relearn procedure that can be used on the Saturn if a scan tool is not available. With the key off, "brain dead" the TCM by disconnecting both battery cables, (remove the negative cable first), and connecting them together. Turn on the headlights and press on the brake pedal to drain the power from the TCM. If you turned the key on to drain the TCM, make sure that you turn the key off before reconnecting the battery. Reconnect the battery (positive 1st, negative last). By draining the power from the TCM, the adaptive learn is cleared to the default level.
Now you can perform the relearn procedures as shown above. It is always a good idea to check to see if the computer has the latest software upgrades. On GM vehicles this is made easy for the aftermarket technician. All you will need is the software calibration number, which can be retrieved by your scanner, and the vehicle VIN#. Go to the FREE GM calibration web site; plug in the VIN# of the vehicle you are working on and all of the software upgrades that are available for that vehicle will appear. Check to see if your calibration # is current. The web address is: http://calid.gm.com.
A Tech 2 or equivalent scan tool must be used to clear the shift adapts in the EEPROM of the TCM, (Saab refers to this procedure as zeroing the adapts). The EEPROM cannot be erased by disconnecting the power from the TCM. The Saab service information says that relearning the shift adapts can be accomplished with a 10-15 minute test drive under varying driving conditions, although they have a specific procedure set down for relearning the up shift, down shift, engagement, and manual down shift adapts.
Resetting the Adapts
Using a Tech 2 or equivalent scan tool, zero out the shift adapts in the EEPROM. The transmission temperature must be 65–110°C for the TCM to relearn the adapts. DO NOT stall test the transaxle to warm it up!
Engagement Relearn Procedure
Up Shift and Down Shift Relearn Procedure
There is a shifting adaptation procedure in the factory manual for those instances where the normal drive does not produce satisfactory results. Always perform the engagement adaptation first, and then perform the shift adaptation procedure as follows:
Manual Shifting From 2nd to 1st Adaptation Relearn Procedure
The AW 55-50 is everywhere and this unit will show up in your shop. As always, builders must learn the proper build techniques for the unit itself. The additional challenge for this unit is to pay careful attention to the specific program and control influences each manufacturer has applied.
Jeff Parlee is Director of Product Support at Valve Body Xpress and a member of the Sonnax TASC Force® (Technical Automotive Specialties Committee), a group of recognized industry technical specialists, transmission rebuilders and Sonnax Industries Inc. technicians.
June 30, 2008
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