Restore Your Envoy’s Shifting Performance
Is your GMC Envoy’s transmission acting unpredictably? The sudden jerks, delayed shifts, and illuminated check engine light can be more than just an annoyance—they are classic signs of a failing Transmission Control Module (TCM). The TCM is the electronic brain of your automatic transmission, constantly processing data from vehicle sensors to ensure smooth, precise, and efficient gear changes. Over time, exposure to engine bay heat, constant vibration, and electrical fluctuations can degrade the module’s delicate internal components, leading to communication errors and poor transmission performance.
This T42 Transmission Control Module is the definitive solution for your vehicle’s issues. It arrives pre-programmed to your vehicle’s specific VIN, eliminating the need for expensive and time-consuming dealership programming. This ensures a seamless, plug-and-play installation that restores your vehicle’s original shifting logic and performance right out of the box.
From the Diagnostic Bay
A customer brought in a 2008 Sierra with classic TCM failure symptoms—a harsh 1-2 shift and getting stuck in 3rd gear (limp mode). They had already replaced two shift solenoids inside the transmission, thinking it was a mechanical issue. A quick scan showed communication loss codes with the TCM. We installed a VIN-programmed module like this one, and the truck shifted perfectly. Always check the TCM first before diving into the transmission itself; it can save you hundreds in unnecessary repairs.
Symptoms of a Failing T42 TCM
- ✔ Unpredictable, erratic, or harsh gear changes.
- ✔ Vehicle enters ‘limp mode,’ refusing to shift past 2nd or 3rd gear.
- ✔ Transmission or Check Engine warning lights are illuminated on the dashboard.
- ✔ Diagnostic trouble codes (DTCs) such as P0700 or solenoid-specific faults are present.
- ✔ A noticeable decrease in fuel economy due to inefficient shifting patterns.
- ✔ Complete loss of gear engagement or communication with the transmission.
Diagnosing and Replacing Your 2006-2009 Envoy TCM
Installation is a straightforward process for the competent DIY mechanic and typically takes less than 30 minutes. The module is located in the engine bay—common locations include the LH engine compartment, next to the battery, or under the air cleaner housing, depending on your specific model. To begin, always disconnect the vehicle’s battery to prevent electrical damage and help reset the system. Then, carefully unplug the electrical connectors from the old TCM, unbolt it from its mounting bracket, and install the new one in its place. Reconnect the battery and connectors. After installation, we recommend using a basic OBD2 scan tool to clear any stored fault codes for a clean slate. With our pre-programmed module, your 2006-2009 Envoy TCM replacement gets you back on the road quickly and without hassle.
Broad GM Compatibility
While this is a perfect fit for the 2006-2009 GMC Envoy, this versatile T42 module is also the correct component for a vast range of General Motors vehicles equipped with 4-speed automatic transmissions like the 4L60E, 4L65E, and 4L70E. It is compatible with popular models such as the Chevrolet Silverado, Tahoe, Impala; GMC Sierra, Yukon; Buick LaCrosse; Cadillac DTS; and many more. It directly interchanges with numerous part numbers, including 24252114, 24234503, 24234274, and 24256960, ensuring wide application coverage.
Frequently Asked Questions
What does ‘VIN Programmed’ mean for me?
VIN programming means we load your vehicle’s specific identification number and the latest GM software onto the module before shipping. This makes the unit plug-and-play, allowing it to communicate perfectly with your vehicle’s other computers without requiring a trip to the dealership for expensive calibration.
Is this a difficult part to install myself?
For most individuals with basic mechanical skills and tools, this is a very manageable job. The module is typically in an accessible location in the engine bay. The process involves disconnecting the battery, unplugging a few connectors, and removing a few bolts. No special tools are required.
Will this fix a P0700 trouble code?
A P0700 code is a general transmission fault request from the TCM to turn on the check engine light. While a faulty TCM is a very common cause for this code, it’s essential to scan for other transmission-specific codes (like P0751, P0756, etc.) to confirm the diagnosis. In many cases, replacing the TCM will resolve the root cause of a P0700 code.
Do I need to send my old module back?
No core charge is required for this part. You can keep your old module, which saves you the time and hassle of packaging and shipping a return.
How do I know this part is compatible with my vehicle?
This module fits a wide range of GM vehicles from 2006-2014. The best way to confirm compatibility is to match the part number (24230461 or one of its interchanges) from your original module. You can also use our website’s vehicle selector or contact our support team with your VIN for guaranteed fitment.