Is Your GMC Envoy Shifting Erratically?
If you’re experiencing harsh shifts, delayed gear engagement, or your 2006-2009 GMC Envoy is stuck in limp mode, a failing Transmission Control Module (TCM) is the most likely culprit. The TCM is the electronic brain of your automatic transmission, responsible for orchestrating every gear change, managing torque converter lockup, and ensuring smooth, efficient operation. When it begins to fail, it can cause a cascade of frustrating and potentially damaging issues, from poor fuel economy to a complete inability to shift gears.
This genuine OEM-quality T42 TCM, part number 24241806, is the definitive solution to restore your vehicle’s transmission performance. Unlike generic modules that require expensive and time-consuming trips to the dealership for programming, this unit arrives at your door pre-programmed to your vehicle’s specific Vehicle Identification Number (VIN). This ensures a seamless, plug-and-play installation that gets you back on the road quickly and confidently.
From the Diagnostic Bay
We recently had a 2008 Envoy roll into the shop with a classic case of intermittent transmission woes. The customer reported that most days it drove fine, but occasionally it would slam into gear or refuse to upshift from second. They had already replaced two shift solenoids with no improvement. After hooking up our scan tool, we saw a generic P0700 transmission fault code, but no specific solenoid codes. Live data showed erratic pressure readings that didn’t match the commanded state. Instead of throwing more parts at it, we inspected the TCM. We found no visible damage, but experience pointed to an internal electronic failure. We installed one of our VIN-programmed T42 modules, cleared the codes, and took it for a lengthy test drive. The shifting was immediately crisp and smooth, just like it left the factory. The customer called a week later to say their Envoy had never driven better. This is a prime example of how a faulty module can mimic mechanical issues, making a direct-fit, programmed 2006-2009 Envoy TCM the correct and final repair.
Diagnosing a Faulty 2006-2009 Envoy TCM
A failing transmission computer can manifest in several ways, often being mistaken for internal transmission failure. Before condemning your transmission, check for these common symptoms that point directly to the TCM. Replacing the module is a far less intensive and costly repair than a complete transmission rebuild.
Symptoms of a Bad Transmission Control Module
- âś” Harsh, erratic, or delayed shifting between gears.
- âś” Vehicle is stuck in a single gear (limp mode), often 2nd or 3rd.
- âś” The check engine light or transmission warning light is illuminated on the dashboard.
- âś” Diagnostic Trouble Codes (DTCs) such as P0700, P0750, P0753, P0758, or other solenoid-related codes are present.
- âś” Inability to shift into higher or lower gears.
- âś” A noticeable decrease in fuel efficiency.
- âś” The transmission seems to slip out of gear unexpectedly.
- âś” Complete loss of communication with the module, preventing diagnostics.
The Plug-and-Play Advantage
Our key service is providing a module that works right out of the box. We flash the unit with the latest GM software updates and program it using the VIN you provide at checkout. This critical step ensures that the TCM communicates perfectly with your Envoy’s Engine Control Unit (ECU) and other vehicle systems, optimizing shift points, fuel economy, and overall powertrain performance. There is no need for additional setup with expensive scan tools or a visit to a dealership.
Installation is straightforward for a DIY mechanic or professional technician. On the 2006-2009 GMC Envoy, the TCM is typically located in the engine compartment on the driver’s side. Simply disconnect the vehicle’s battery, unplug the electrical connectors from the old module, unbolt it, and install the new one in its place. Reconnect the battery, and you’re ready to go. We recommend clearing any stored DTCs with a basic scan tool after installation to ensure a clean slate for the new module.
What is a TCM and what does it do?
The Transmission Control Module (TCM) is a computer that controls your vehicle’s automatic transmission. It uses data from various sensors, like vehicle speed and engine RPM, to determine the perfect moment to shift gears, control fluid pressure, and engage the torque converter clutch for optimal performance and fuel economy.
Will this module fit vehicles other than the GMC Envoy?
Yes. This T42 TCM is compatible with a wide range of 2006-2014 General Motors vehicles equipped with 4-speed automatic transmissions like the 4L60E, 4L65E, and 4L70E. This includes models like the Chevrolet Silverado, Tahoe, Impala; GMC Sierra, Yukon; Cadillac DTS; and many others. Please verify your part number or use our vehicle fitment tool to ensure compatibility.
Do I need to send my old part back?
No, there is no core charge for this module. You can keep your old part, which saves you the time and hassle of packaging and shipping it back to us.
Is any special programming required after installation?
No. This module comes pre-programmed to your vehicle’s VIN. It is a true plug-and-play solution. You do not need to take it to a dealer or mechanic for additional programming. Just install it, clear any old codes, and drive.
Where is the TCM located on my vehicle?
The location varies by model. On the 2006-2009 GMC Envoy, it’s typically in the LH (driver’s side) engine compartment. On other vehicles like a Silverado or Tahoe, it’s often found next to the battery. For models like the Impala or LaCrosse, it may be under the air cleaner housing. Always consult a service manual for your specific vehicle if you are unsure.