If your 2006 GMC Envoy XL is suffering from erratic shifting, getting stuck in gear, or throwing transmission codes, you’ve come to the right place. As a technician with over two decades of experience under the hood, I’ve seen countless drivers frustrated by these exact issues. Often, the root cause isn’t a catastrophic mechanical failure but a faulty Transmission Control Module (TCM). This VIN-programmed T42 TCM, part number 24256960, is the definitive, reliable solution to restore the crisp, predictable performance your vehicle had when it was new.
The TCM is the brain of your automatic transmission, constantly communicating with the engine computer to manage shift points, torque converter lockup, and line pressure. When it fails, the symptoms can range from annoying to debilitating. This module is expertly pre-programmed to your vehicle’s specific VIN, ensuring it works perfectly right out of the box. You get the latest GM software updates without the hassle, time, and expense of a dealership visit for programming. It’s a true plug-and-play fix.
A Technician’s Notebook
I remember a customer with a 2008 Silverado who was at his wit’s end. He’d spent a small fortune replacing shift solenoids and the valve body, chasing a persistent P0753 (Shift Solenoid ‘A’ Electrical) code and harsh 1-2 shifts. The truck would drive fine for a day, then fall right back into limp mode. After checking his work, I suspected the TCM. The internal drivers that fire the solenoids can weaken over time, causing intermittent faults that mimic a bad solenoid. We installed one of these pre-programmed T42 modules, and the problem vanished instantly. It’s a classic case where throwing parts at the transmission itself was a waste of money; the electronic controller was the culprit all along.
Is Your Vehicle Exhibiting These Telltale Signs?
A failing TCM can manifest in several ways. If you’re experiencing any of the following, this module is likely the solution you need. In my shop, these symptoms are the classic indicators of a T42 module failure.
- ✔ Harsh, slamming shifts or delayed gear engagement.
- ✔ Vehicle is stuck in ‘limp mode’ (usually second or third gear) with no upshifting.
- ✔ Check Engine Light or Transmission Warning Light is illuminated.
- ✔ Diagnostic Trouble Codes (DTCs) are present, such as P0700, P0750, P0753, P0758, or other solenoid-related faults.
- ✔ Poor acceleration and a noticeable drop in fuel economy.
- ✔ Complete loss of communication with the transmission module (no gear indicator display).
Your 30-Minute Path to Smooth Shifting
One of the best features of this part is its straightforward installation. For most DIYers with basic tools, this is a job you can complete in your driveway in under 30 minutes. The location of the 2006 Envoy XL Transmission Control Module is on the left-hand (driver’s side) of the engine compartment.
- Safety First: Disconnect the negative terminal from your vehicle’s battery to prevent electrical shorts and help reset the system.
- Locate the Module: Find the TCM in your engine bay. On the Envoy XL, it’s typically on the LH side. On other GM models, it might be next to the battery, under the air cleaner box, or on a frame rail. It’s a silver box with several large electrical connectors.
- Disconnect and Remove: Carefully unplug the electrical connectors. There are usually retaining clips that need to be released. Then, unbolt the module from its mounting bracket.
- Install the New TCM: Bolt the new, pre-programmed module into place. Securely plug in the electrical connectors until they click.
- Final Steps: Reconnect the negative battery terminal. While the system often resets, it’s best practice to use a basic OBD-II scan tool to clear any stored DTCs. Start the vehicle and enjoy your smooth-shifting transmission!
Verified Fitment for Your General Motors Vehicle
This T42 TCM is a direct replacement for a wide range of GM cars, trucks, and SUVs equipped with 4-speed automatic transmissions like the 4L60E, 4L65E, and 4L70E. It is compatible with part numbers 24256960, 24252114, 24234503, and many more.
This part will fit these makes and models with these options
ENVOY 08-09 Transmission; (LH engine compartment)
SAVANA 3500 VAN 06-14 Transmission; (RH engine compartment)
VUE 07-08 Transmission; 2.4L, (LH front engine compartment)
G5 07-10 Transmission; (LH strut tower)
SIERRA 1500 PICKUP 07 Transmission; (new style, smooth door skin), (next to battery)
LUCERNE 06-07 Transmission; (4.6L), (LH engine compartment)
VUE 09 Transmission; 2.4L, w/hybrid, LH side front engine compartment, (shift control)
VUE 10 Transmission
TAHOE 08-09 Transmission; (next to battery), w/o auxiliary oil cooler pump
YUKON XL 1500 07-08 Transmission; (next to battery)
AURA 07-09 Transmission; (LH frame rail front)
RENDEZVOUS 06-07 Transmission; (air cleaner box)
SAAB 9-7X 06-09 Transmission; (LH engine compartment)
SAVANA 2500 VAN 06-14 Transmission; (RH engine compartment)
ALLURE 06-09 Transmission; (lower air cleaner housing)
LUCERNE 08-11 Transmission; (LH engine compartment)
RAINIER 06-07 Transmission
SILVERADO 1500 PICKUP 07 Transmission; (new style, smooth door skin), (next to battery)
SILVERADO 1500 PICKUP 09-13 Transmission; (next to battery), w/o hybrid option
YUKON 09 Transmission; (next to battery), w/o auxiliary oil cooler pump
ENVOY 06-07 Transmission; (LH engine compartment), (8 cylinder)
MONTE CARLO 06-07 Transmission; (lower air cleaner housing)
YUKON 08 Transmission; (next to battery), w/o auxiliary oil cooler control
EXPRESS 1500 VAN 06-14 Transmission; (RH engine compartment)
SSR 05-06 Transmission; (front LH frame)
SAVANA 1500 VAN 06-14 Transmission; (RH engine compartment)
SIERRA 1500 PICKUP 09-13 Transmission; (next to battery), w/o hybrid option
EXPRESS 3500 VAN 06-14 Transmission; (RH engine compartment)
ION 06-07 Transmission; (behind LH strut tower)
PURSUIT 06 Transmission; (LH strut tower)
TAHOE 07 Transmission; (next to battery)
ENVOY XL 06 Transmission; (LH engine compartment), (8 cylinder)
EXPRESS 2500 VAN 06-14 Transmission; (RH engine compartment)
IMPALA 06-11 Transmission; (lower air cleaner housing)
MONTANA 06-09 Transmission; (LH strut tower)
TRAILBLAZER 08-09 Transmission; (LH engine compartment)
YUKON 07 Transmission; (next to battery)
G6 06-10 Transmission; (LH strut tower)
HHR 06-11 Transmission; (LH engine compartment)
TRAILBLAZER 06-07 Transmission; (LH engine compartment), (8 cylinder)
AVALANCHE 1500 07-08 Transmission; (next to battery)
COBALT 06-10 Transmission; (LH strut tower)
SIERRA 1500 PICKUP 08 Transmission; (next to battery)
SILVERADO 1500 PICKUP 08 Transmission; (next to battery)
LACROSSE 06-09 Transmission; (lower air cleaner housing)
SIERRA 2500 PICKUP 07 Transmission; new style (smooth door skin), 6.0L, (next to battery)
SILVERADO 2500 PICKUP 07 Transmission; new style (smooth door skin), 6.0L, (next to battery)
COLORADO 08-12 Transmission; (RH rear engine compartment)
SUBURBAN 1500 07-08 Transmission; (next to battery)
VUE 09 Transmission; 2.4L, w/o hybrid; (LH front engine compartment)
CANYON 08-12 Transmission; (RH rear engine compartment)
DTS 06-11 Transmission; (RH front engine compartment)
MALIBU 06-10 Transmission; (LH frame rail)
GRAND PRIX 06-08 Transmission; (lower air cleaner housing)
HUMMER H3 08-10 Transmission; (RH rear engine compartment)
TERRAZA 06-07 Transmission; (LH strut tower)
TRAILBLAZER EXT 06 Transmission; (LH engine compartment), (8 cylinder)
UPLANDER 06-09 Transmission; (LH strut tower)
Frequently Asked Questions
Frequently Asked Questions
What does ‘VIN Programmed’ actually mean?
It means we load your vehicle’s unique 17-digit Vehicle Identification Number (VIN) and the latest GM software onto the module before we ship it. This ensures it communicates perfectly with your specific vehicle’s engine and other systems, eliminating the need for a dealership to program it.
Do I need to send my old TCM back?
No, there is no core charge or need to return your old part. You can keep it or dispose of it, making the repair process simpler and faster for you.
Will this fix my specific transmission code, like P0700?
A P0700 is a general fault code indicating the TCM has requested the check engine light. The true problem lies in the other codes stored within the TCM (like solenoid or pressure switch faults). This module is the direct solution for those internal electronic failures that cause these codes.
Is this a difficult part for a DIYer to install?
Not at all. For most of the vehicles this fits, the TCM is easily accessible in the engine bay. With basic hand tools and our simple instructions, most people can swap the module in under 30 minutes.
Is this the same part as the Engine Control Module (ECM)?
No. This is the Transmission Control Module (TCM), which specifically controls the automatic transmission. The Engine Control Module (ECM), or Powertrain Control Module (PCM) in some vehicles, manages engine functions. They are separate components.