End Frustrating Transmission Problems in Your 2006 Trailblazer EXT
If your 2006 Chevrolet Trailblazer EXT is suffering from erratic shifting, getting stuck in gear, or has the dreaded check engine light on with transmission codes, you’ve likely pinpointed a failing Transmission Control Module (TCM). As a technician with over two decades of experience, I’ve seen firsthand how a faulty T42 TCM can bring an otherwise reliable SUV to a standstill. This isn’t just an inconvenience; it’s a critical failure that compromises vehicle performance and safety. This module is the solution—a high-quality, direct-fit replacement for part number 24252114, pre-programmed to your vehicle’s specific VIN for a true plug-and-play repair.
The TCM is the brain of your automatic transmission, responsible for orchestrating every gear change, managing torque converter clutch lockup, and communicating with the engine computer. When it fails, the symptoms are impossible to ignore. Our module restores this crucial communication, ensuring your 4-speed automatic (like the 4L60E or 4L65E) operates with the precision it was designed for.
Case Study: A Tricky Diagnosis
A customer brought in a 2006 Envoy—a cousin to the Trailblazer—with a classic complaint: it was stuck in 3rd gear (limp mode) and had a P0700 code. Another shop had already replaced two shift solenoids without success. After a quick scan and checking the wiring harness for damage (a common issue on these GMT360 platforms), I suspected the T42 module. Heat cycles and vibrations cause internal solder joints to fail over time. We installed one of our VIN-programmed modules, and in less than an hour, the vehicle was shifting perfectly. The customer saved hundreds by avoiding further guesswork and an expensive trip to the dealer.
Is Your Trailblazer Showing These Telltale Signs?
A failing TCM will give you clear warnings. If you’re experiencing any of the following, it’s time for a replacement:
- ✔ Harsh, banging shifts or delayed gear engagement.
- ✔ The vehicle is stuck in a single gear (often called ‘limp mode’).
- ✔ Check Engine Light is on with transmission-related Diagnostic Trouble Codes (DTCs) such as P0700, P0753, P0758, or other solenoid circuit faults.
- ✔ Inability to upshift or downshift, leading to poor acceleration and terrible gas mileage.
- ✔ The transmission temperature warning light comes on prematurely.
- ✔ Complete loss of communication with the transmission module, preventing diagnostics.
A Straightforward Guide to Installation
One of the best features of this part is its simple installation, which most DIYers can complete in their driveway in under 30 minutes. For the 2006 Trailblazer EXT, the TCM is typically located in the left-hand (driver’s side) engine compartment.
- Safety First: Always disconnect the negative terminal from your vehicle’s battery before starting any electrical work. This prevents short circuits and helps reset the vehicle’s computer systems.
- Locate the Module: Find the old TCM. It’s a silver box with electrical connectors, usually mounted to the firewall or inner fender on the driver’s side.
- Disconnect and Remove: Carefully unclip the wiring harness connectors. Then, unbolt the module from its mounting bracket. There are typically two or three small bolts holding it in place.
- Install the New Module: Bolt the new, pre-programmed TCM into the same location. Ensure it is securely mounted.
- Reconnect and Finalize: Firmly plug the wiring harness connectors back into the new module. You should hear a click. Reconnect the negative battery terminal. Use a basic OBD2 scan tool to clear any stored fault codes before starting the vehicle.
Guaranteed Fitment for Your GM Vehicle
This T42 TCM is a direct replacement for part number 24252114 and is compatible with a wide range of GM vehicles. While this page focuses on the 2006 Trailblazer EXT TCM, it also fits the models listed below. Please verify the location noted for your specific vehicle.
- Chevrolet Trailblazer EXT (8 cylinder): 2006 (LH engine compartment)
- Chevrolet Silverado & GMC Sierra: 2007-2013 (various, typically next to battery)
- Chevrolet Tahoe & GMC Yukon: 2007-2009 (next to battery)
- Chevrolet Express & GMC Savana Vans: 2006-2014 (RH engine compartment)
- Chevrolet Impala / Monte Carlo: 2006-2011 (lower air cleaner housing)
- Pontiac G6 / Grand Prix: 2006-2010 (LH strut tower)
- Buick LaCrosse / Lucerne: 2006-2011 (various, LH engine compartment or under air cleaner)
- Hummer H3: 2008-2010 (RH rear engine compartment)
- …and many other GM models from 2006-2014.
Frequently Asked Questions
Frequently Asked Questions
Do I need to take my vehicle to the dealer for programming?
No. This is the biggest benefit. We program the module to your vehicle’s VIN before shipping it. This means it’s ready for installation right out of the box, saving you time and the high cost of dealership programming.
Is this part difficult to install myself?
Not at all. For most vehicles, including the 2006 Trailblazer EXT, it’s a simple bolt-off, bolt-on process that takes less than 30 minutes with basic hand tools. Our installation guide above walks you through the steps.
What is a ‘core charge’ and do you require one?
A core charge is a deposit you pay until you return your old part. We do not require a core charge, so you can keep your old module without any hassle or extra cost.
Will this fix a P0700 trouble code?
A P0700 code is a general transmission fault request, meaning the TCM has detected a problem and asked the main computer to turn on the check engine light. If the underlying cause is a faulty TCM or a component it controls, replacing the module will resolve the code once the system is cleared.
What information do you need to program the module?
We only need your vehicle’s 17-digit Vehicle Identification Number (VIN). You can typically find this on your driver’s side dashboard (visible through the windshield) or on the door jamb sticker.