Restore Peak Transmission Performance in Your GM Vehicle
Is your 2006-2009 Chevrolet Trailblazer, GMC Envoy, or other compatible GM vehicle suffering from erratic shifting, getting stuck in gear, or displaying transmission-related error codes? These are classic signs of a failing Transmission Control Module (TCM). This genuine OEM-quality T42 TCM, part number 24239926, is the definitive solution to restore the crisp, reliable shifting you expect. As the electronic brain of your automatic transmission, the TCM is responsible for managing shift points, torque converter clutch engagement, and line pressure. When it fails, drivability is severely compromised. Our module arrives expertly programmed to your vehicle’s specific VIN, eliminating the need for expensive dealership programming and ensuring a true plug-and-play installation.
From the Diagnostic Bay
We recently had a 2008 GMC Sierra in the shop with a classic complaint: harsh 1-2 shifts and occasionally getting stuck in 3rd gear (limp mode). The customer had already spent a small fortune replacing shift solenoids based on a generic code reader’s output, but the problem persisted. After a quick scan with professional equipment, we saw communication errors pointing directly to the TCM. The internal circuits were failing intermittently, especially when hot. We installed one of our VIN-programmed T42 modules. The installation took less than 20 minutes, and on the first test drive, the truck shifted perfectly. It’s a common story: mechanics often chase symptoms inside the transmission when the real culprit is the external controller. Replacing the TCM first can save hundreds in unnecessary labor and parts.
Symptoms of a Failing T42 Transmission Control Module
- ✔ Hard, delayed, or unpredictable gear shifts.
- ✔ Vehicle is stuck in a single gear, often referred to as “limp mode.”
- ✔ Check Engine Light or Transmission Warning Light is illuminated on the dash.
- ✔ Diagnostic Trouble Codes (DTCs) such as P0700, P0750, or other solenoid-related codes are present.
- ✔ Poor acceleration and reduced fuel economy.
- ✔ Complete loss of gear engagement or intermittent communication failure with the module.
Why Choose Our Programmed 2006-2009 Trailblazer TCM?
Choosing the right replacement part is critical for a lasting repair. Our T42 TCM is not just a component; it’s a complete solution. The primary benefit is our professional VIN programming service. We load the latest GM software and calibrate the module specifically to your vehicle’s VIN before it ships. This ensures that all transmission parameters and shift strategies are perfectly matched to your vehicle’s original specifications. This process resolves common software-related DTCs and guarantees optimal performance and fuel efficiency right out of the box. This module is a direct replacement for a wide range of part numbers, including 24252114, 24234503, 24230461, and more, making it a versatile fix for dozens of GM models from trucks and SUVs to sedans.
Installation and Compatibility
Installation is straightforward for a DIY mechanic or professional technician. The module is typically located in the engine bay—often near the battery, on a strut tower, or under the air cleaner box. 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 everything, and you’re ready to go. Because our 2006-2009 Trailblazer TCM is pre-programmed, there are no complex relearn procedures required. This module fits an extensive list of vehicles including the Chevrolet Silverado, Tahoe, Impala; GMC Sierra, Yukon, Savana; Buick LaCrosse; Cadillac DTS; Hummer H3, and many others equipped with 4-speed automatic transmissions like the 4L60E, 4L65E, and 4L70E.
Frequently Asked Questions
What does VIN programming mean for me?
VIN programming means we pre-load the module with your vehicle’s specific factory software and settings using your Vehicle Identification Number. This makes the unit plug-and-play, allowing you to avoid a trip to the dealership for expensive programming. It ensures perfect communication between the TCM and your vehicle’s other systems.
Is this a difficult part to install myself?
For most individuals with basic mechanical skills, this is a very manageable job. The TCM is usually in an accessible location in the engine bay. The process involves disconnecting the battery, unplugging two electrical connectors, and removing a few bolts. The entire process typically takes less than 30 minutes.
Will this TCM fix a P0700 trouble code?
A P0700 code is a general transmission fault request from the TCM to the Engine Control Module (ECM) to turn on the check engine light. While a faulty TCM can cause a P0700, this code indicates that more specific transmission codes are stored in the TCM itself. This module will fix the issue if the underlying cause is a faulty TCM, which is a very common scenario.
Do I need to send my old module back?
No, there is no core charge for this part. You can keep your old module or dispose of it without any need to return it to us, simplifying the process for you.
How do I know the TCM is the problem and not the transmission itself?
While a full diagnosis is always best, TCM failure often presents with electronic symptoms like erratic behavior, communication error codes, or problems that are intermittent or change with temperature. Mechanical transmission failures often involve consistent noises, slipping that gets progressively worse, or burnt fluid. If you have multiple solenoid codes at once, it often points to the controller (the TCM) rather than all the solenoids failing simultaneously.