If your 2006-2009 GMC Envoy is suffering from erratic shifting, getting stuck in gear, or has the check engine light on with transmission codes, you’ve come to the right place. As a technician with over two decades of experience, I’ve seen firsthand how a failing Transmission Control Module (TCM) can turn a reliable SUV into a source of constant frustration. This isn’t just an inconvenience; it’s a critical failure that compromises your vehicle’s performance and safety. This direct-fit T42 TCM, service part number 24235340, is the definitive solution to restore the crisp, predictable shifting your vehicle had when it was new.
The TCM is the electronic brain of your 4L60E or 4L65E automatic transmission. It constantly analyzes data from engine speed, vehicle speed, and throttle position sensors to command precise gear changes and manage torque converter lockup for optimal fuel efficiency. When it fails, the communication breaks down, leading to the jarring shifts and limp mode you might be experiencing. Our module solves this problem by arriving pre-programmed to your vehicle’s specific VIN, eliminating the need for a costly trip to the dealership for programming.
Case Study: A Tricky Diagnosis
I remember a 2008 Envoy that came into my shop with a maddeningly intermittent issue. The owner complained of harsh 1-2 shifts, but only after the vehicle was fully warmed up. Sometimes it would throw a P0751 (Shift Solenoid ‘A’ Performance/Stuck Off) code, but the solenoid itself tested fine. We checked the wiring and fluid, but found no issues. The problem pointed towards the module’s driver for that solenoid failing under heat. We installed one of our VIN-programmed T42 modules, and the problem vanished instantly. The customer was thrilled to have his smooth-shifting Envoy back without paying dealership diagnostic and programming fees. This is a classic example of how a quality Envoy Transmission Control Module saves time and money.
Is Your Envoy Exhibiting These Telltale Signs?
A failing TCM will give you clear warnings. If you’re noticing any of the following, it’s a strong indicator that your module needs replacement:
- âś” Harsh, banging shifts or delayed gear engagement.
- âś” The vehicle is stuck in a single gear (often 2nd or 3rd), a condition known as “limp mode.”
- âś” An illuminated Check Engine Light or Transmission Warning Light.
- âś” Diagnostic Trouble Codes (DTCs) stored in the computer, such as P0700, P0750, P0751, or other solenoid-related faults.
- âś” Inability to upshift or downshift, leading to poor acceleration and terrible fuel economy.
- âś” Complete loss of communication with the transmission.
Your Step-by-Step Guide to a Hassle-Free Installation
One of the best features of this part is its simple installation. You don’t need to be a master mechanic to get this job done in your own driveway in under 30 minutes. For the GMC Envoy, the TCM is typically located in the left-hand (driver’s side) engine compartment.
- 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: Find the TCM on the driver’s side of the engine bay. It’s a silver box with electrical connectors.
- Disconnect and Remove: Carefully unclip the wiring harnesses. Then, unbolt the module from its mounting bracket.
- Install the New Module: Bolt the new Envoy Transmission Control Module into place and securely reconnect the wiring harnesses. Ensure they click into place.
- Final Steps: Reconnect the battery terminal. While our programming handles the heavy lifting, it’s good practice to use a basic OBD2 scanner to clear any old fault codes from the vehicle’s memory.
Verified Fitment For Your GM Vehicle
While this is the perfect solution for your 2006-2009 GMC Envoy, this T42 TCM is also compatible with a wide range of other General Motors cars, trucks, and SUVs. It is a direct replacement for multiple part numbers, including 24252114, 24234503, and 24235340. Please verify your vehicle in the list below:
- GMC: Envoy (06-09), Sierra 1500/2500 (07-13), Yukon (07-09), Savana 1500/2500/3500 (06-14), Canyon (08-12)
- Chevrolet: Silverado 1500/2500 (07-13), Tahoe (07-09), Suburban 1500 (07-08), Avalanche 1500 (07-08), Express 1500/2500/3500 (06-14), Impala (06-11), Cobalt (06-10), HHR (06-11), Colorado (08-12), Trailblazer (06-09)
- Cadillac: DTS (06-11)
- Buick: LaCrosse (06-09), Lucerne (06-11), Allure (06-09), Rainier (06-07)
- Pontiac: G6 (06-10), Grand Prix (06-08)
- Saturn: Vue (07-10), Aura (07-09), Ion (06-07)
- Hummer: H3 (08-10)
- Saab: 9-7X (06-09)
Frequently Asked Questions
Do I need to take my vehicle to the dealer for programming?
No. This module comes fully programmed to your vehicle’s VIN. It is a true plug-and-play solution, saving you time and the high cost of dealership programming.
What is a core charge? Do I need to send my old part back?
There is absolutely no core charge. You can keep your old module or dispose of it, making the process simple and hassle-free.
Will this fix a P0700 trouble code?
A P0700 code is a generic request from the TCM to turn on the check engine light. The true problem lies in the specific codes stored within the TCM (like solenoid or sensor faults). If the TCM itself is the source of these faults, then yes, replacing it with our quality Envoy Transmission Control Module is the correct fix.
Is this part difficult to install for a DIYer?
Not at all. The installation is very straightforward, typically requiring only basic hand tools to unbolt the old module and connect the new one. The entire process can usually be completed in under 30 minutes.
What kind of warranty comes with this module?
We stand behind our parts with a comprehensive one-year warranty, giving you peace of mind that you are installing a reliable and durable component.