Restore Smooth Shifting to Your GM Vehicle
If you’re dealing with the headaches of a faulty transmission—erratic shifting, a car that won’t shift out of gear, or a persistent check engine light—you’re not alone. As a technician with over two decades of experience, I’ve seen countless GM trucks and SUVs sidelined by a failed Transmission Control Module (TCM). The TCM is the brain of your automatic transmission, and when it fails, it can make your vehicle unpredictable and unsafe to drive. This T42 TCM, corresponding to part number 24243921, is the definitive solution for your 2006 Envoy XL TCM and a wide range of other GM models, designed to restore factory performance and reliability.
The biggest hurdle with electronic module replacement has always been the expensive and time-consuming trip to the dealership for programming. We eliminate that step entirely. By providing your vehicle’s VIN at checkout, we program the module with the latest GM software updates specifically for your vehicle. This means it arrives at your door ready for a true plug-and-play installation, getting you back on the road faster and saving you hundreds of dollars in dealer fees.
From the Diagnostic Bay
I recently had a 2007 Chevy Trailblazer (which shares its platform with the Envoy) come into the shop. The customer was frustrated; he’d already replaced two shift solenoids based on some generic advice, but the transmission was still shifting hard from 1st to 2nd and occasionally throwing a P0700 code. After a quick scan and checking the wiring, my experience pointed straight to the TCM. These T42 modules are notorious for internal solder joint failures after years of heat cycles. We installed one of our pre-programmed units, and the problem was solved in under 20 minutes. The customer was thrilled to have his truck driving like new again without another expensive guess. This isn’t just a part; it’s a permanent fix for a known issue.
Is Your Envoy Exhibiting These Telltale Signs?
A failing TCM will give you clear warnings. If you’re experiencing any of the following, it’s highly likely your module is the culprit. This part is a direct fix for these common issues and associated Diagnostic Trouble Codes (DTCs).
- ✔ Harsh, slamming, or delayed gear shifts.
- ✔ Vehicle is stuck in “limp mode” (usually second or third gear).
- ✔ Check Engine Light or Transmission Warning Light is on.
- ✔ Common DTCs stored, such as P0700 (Transmission Control System Malfunction), P0750-P0758 (Shift Solenoid Errors).
- ✔ Failure to upshift or downshift properly.
- ✔ A sudden, noticeable drop in fuel economy.
- ✔ Complete loss of communication with the transmission module.
DIY Installation: A 30-Minute Fix
You don’t need to be a professional mechanic to replace this module. With basic hand tools, you can complete this job in your own driveway. The location varies slightly by model, but it’s always accessible in the engine bay.
- Safety First: Disconnect the negative terminal from your vehicle’s battery to prevent any electrical shorts and to help reset the system.
- Locate the Module: On the 2006 Envoy XL TCM, it’s typically found in the left-hand (driver’s side) of the engine compartment. On other models, it may be next to the battery or under the air cleaner box.
- Disconnect and Remove: Carefully unplug the electrical connectors. They have locking tabs that need to be released. Then, unbolt the module from its mounting bracket.
- Install the New Module: Bolt the new, pre-programmed TCM into place and securely reconnect the electrical harnesses. Ensure they click into place.
- Final Steps: Reconnect the battery terminal. While the module is plug-and-play, it’s good practice to use a basic OBD2 scanner to clear any old fault codes from the vehicle’s memory.
Verified Vehicle Compatibility List
This T42 TCM is a direct replacement for a wide array of General Motors vehicles equipped with 4-speed automatic transmissions like the 4L60E, 4L65E, and 4L70E. It is interchangeable with numerous part numbers, including 24252114, 24234503, 24243901, and more. Please verify your model and options below.
- ENVOY XL: 2006 (8 cylinder, LH engine compartment)
- ENVOY: 2006-09 (8 cylinder, LH engine compartment)
- TRAILBLAZER / TRAILBLAZER EXT: 2006-09 (8 cylinder, LH engine compartment)
- CHEVROLET SILVERADO / GMC SIERRA 1500/2500: 2007-2013 (Located next to battery)
- CHEVROLET TAHOE / GMC YUKON: 2007-2009 (Located next to battery)
- CHEVROLET EXPRESS / GMC SAVANA VANS: 2006-2014 (RH engine compartment)
- CADILLAC DTS: 2006-2011 (RH front engine compartment)
- BUICK LACROSSE / ALLURE / LUCERNE: 2006-2011
- PONTIAC G6 / GRAND PRIX: 2006-2010
- CHEVROLET IMPALA / MONTE CARLO: 2006-2011
- …and many more models including the Cobalt, HHR, Saturn Vue, Hummer H3, and Saab 9-7X.
Frequently Asked Questions
What does ‘VIN Programmed’ actually mean for me?
It means the module arrives ready to install right out of the box. We use your Vehicle Identification Number (VIN) to load the correct factory software for your specific vehicle’s configuration. This allows the TCM to communicate perfectly with your engine and other systems, ensuring proper shift points and performance without needing a trip to the dealer.
Do I need any special tools for installation?
No special tools are required. Basic hand tools like a socket set and a screwdriver are typically all you need. The most important part is ensuring the battery is disconnected before you begin.
Will this fix my transmission codes like P0700?
Yes. In the vast majority of cases, a faulty TCM is the root cause of a P0700 code, as well as various shift solenoid codes. Replacing the module with this pre-programmed unit is the direct and proper repair for these electronic failures.
Is there a core charge for my old part?
No, there is absolutely no core charge. You can keep your old part or dispose of it at your convenience without the hassle of shipping it back to us.
What kind of warranty is included?
We stand behind our products. This transmission control module comes with a comprehensive one-year warranty, giving you peace of mind and protection for your investment.