Transmission programming modules: When to reprogram and when to replace

Transmission programming modules: When to reprogram and when to replace

Programming modules have been an essential aspect of the complete repair and service experience (Figure 1) within the automotive industry for quite some time now. Not providing this service shortchanges both the shop and the customer; yes, the repair has been performed, but the vehicle is still not working as well as it could be. Aside from fine-tuning the work performed, programming the latest calibration updates into the vehicle often resolves issues beyond the specific repair completed. When it does, it’s always nice to hear a customer say, “My car never ran so well.”

Figure 1.

When it comes to programming modules that control automotive transmissions, there is a difference between reprogramming and replacing a program, and it is all a matter of clicking the correct button (Figure 2).

Technically Speaking June Figure 3
Figure 2.

To clarify, to “Reprogram” means to update the existing calibration with the latest software available. One such example of needing to “Reprogram” is if a vehicle comes to a shop exhibiting symptoms and/or codes that a TSB is addressing by updating the calibration to the latest software. To “Replace and Program” is to write a completely new and updated calibration. This is needed when fully replacing a transmission with either a new, remanufactured or used transmission.

When it comes to a TEHCM used in a GM 6L80 transmission, for instance, we have discovered that it is not overly sensitive to the VIN. Nor does it seem to be sensitive to GM’s Global Diagnostic System (GDS). Let me explain. This new security protocol was introduced here in the U.S. in 2010 and by 2014 was being used in all platforms. This Global Diagnostic System is often referred to as GM’s “Global A” system. The Body Control Module is the controlling module for the GDS system. It sends an “Identifier” signal over the serial data lines to which GDS compliant modules must respond by comparing module identification to the identification originally programmed into the BCM. If the BCM identifier is not recognized or receives an incorrect identifier from one of the other GDS compliant modules, it will respond by preventing the vehicle from starting. 

Read more stories from our Technically Speaking column series here.

With this brief understanding of what GDS is, the TEHCM used in a 6L80 transmission has not shown itself to be sensitive to this system. We have seen, on rare occasions, code U0101 setting for a Loss of Communication to the TCM, causing the vehicle to not start due to a variety of reasons unrelated to the GDS. What does occur on a regular basis is that when a previously used module is installed, an error message occurs indicating that there is no communication to the module along with a VIN mismatch. In these cases, the PID display remains functional, and the vehicle will start. 

To remedy a used TEHCM that has a program installed into it associated with a different VIN, the option to “Replace and Reprogram” must be selected in the programming process, NOT just “Reprogram.”  This will allow the correct program associated with the VIN of the vehicle to overwrite the existing program and to install the latest updates, completing an optimum repair.

To be a bit more specific, a shop may be tempted to not perform any programming updates when a used TEHCM is installed from a different vehicle, and it seems to drive well. This is not the best way to send the vehicle out, as in most cases the program is not fitted for the vehicle it is in. Additionally, the latest updates are also not installed. This allows for pesky and annoying problems to lurk within the program that could result in repeated transmission failure; or, at least, continuous complaints from the customer about how the transmission doesn’t seem to shift right.   

One of the more common issues that arises when swapping 6L80 TEHCMs is due to a running change made sometime between 2013 to 2014. New instrument clusters now provide Transmission Fluid Temperature data. This means the TEHCM is fitted with a program to provide both Transmission Temp for the TCM and for the Instrument Cluster. A mismatch in TEHCMs will usually show Trans Temp at -40°F. Replacing and reprogramming will resolve this as well. 

Finally, unrelated to this, is the code that indicates a failure of the TCM itself. It is the code for an Internal TCM Temperature Overheat. This code means you need another TEHCM. It literally means it’s toast!

Was this content valuable?

Thanks for your feedback!

You May Also Like

The importance of the follow-up road test after transmission replacement

A 2002 Lexus RX300 equipped with a 3.0-liter V6 engine and U140F transmission was brought into our facility with a few concerns. The customer said that “it has a leak, a grinding noise when taking off from a stop, and it just doesn’t seem to shift right.” They went on to tell us that this

RR Tech Feature Oct

A 2002 Lexus RX300 equipped with a 3.0-liter V6 engine and U140F transmission was brought into our facility with a few concerns. The customer said that “it has a leak, a grinding noise when taking off from a stop, and it just doesn’t seem to shift right.”

Tips and tricks for Chrysler switch valve plug testing

As technicians, we are often faced with build issues that can sometimes be frustrating at first. But with a little ingenuity, these frustrations can be turned around and made simple. Related Articles – GM 8L90 #7 Check-ball: The overheat that saved the day – ETE Reman: Ever expanding – Shift Pointers: Nissan’s no throttle response

GM 8L90 #7 Check-ball: The overheat that saved the day

Beginning in October of 2015, GM removed the #7 Check-ball from the solenoid valve control body in the 8L90 transmission (see Figure 1). This was done in conjunction with the elimination of the Lube Override Enable Valve from the upper valve body as shown in Figure 2. Related Articles – Jatco/Nissan JF011E critical wear areas

Shift Pointers: Nissan’s no throttle response

Nissan vehicles using continuously variable transmissions (CVTs) are notorious for defaulting to a no throttle response when the vehicle is engaged into gear. There are several malfunctions that can cause this protective failsafe feature to be initiated. A brake switch (stop lamp switch) stuck on, a double-footed driver, blown or incorrect brake bulbs, and wheel

Jatco/Nissan JF011E critical wear areas and vacuum test locations

Sonnax has provided the following guide on critical wear areas and vacuum test locations for the Jatco/Nissan JF011E. Technicians working on these models should find this guide helpful. (Ed. Note: This is an extended version of the guide found in our September issue, with three additional pages). Related Articles – Podcast: Talking CVTs with Transtar,

Other Posts

Watch: CVT modules and programming

CVTs usually will require a reset to the basic factory programming after repairing a major component. You can typically use a scan tool to help complete this. Watch the latest video from Transtar, above, for more. Related Articles – Road to AAPEX season 2 finale: Where the road ends and the show begins – Road

Tips for success with the GM transmission fast learn process

This article is about failure, something we all experience from time to time. If you are attempting to perform a fast learn process on a GM eight-, nine-, or 10-speed transmission, you may have that temporary feeling of failure, as this process can bring on frustration quickly. Let’s talk about what the fast learn process

Shift pointers: Tricky sensor situations

Sometimes you’re the windshield and sometimes you’re the bug—a phrase many of us have heard and experienced. It’s inevitable. The idea is to be the windshield as much as possible. Shane from Cottman Transmissions had a helluva day but in the end, he was the windshield. Related Articles – CVT maintenance basics – Mercedes-Benz 722.9

Look for the little details: Three transmission repair case studies

Below are three examples of trucks that came into transmission shops, yet either did not have a transmission problem, or had a simpler issue than it originally seemed. Read on for the stories. Related Articles – Infiniti G37 RE7R01A chassis codes set – Honda Accord BB7A six-speed: P2720 code set after collision – Troubleshooting RFE