Restore Smooth, Reliable Shifting to Your GM Vehicle
If you’re dealing with the frustration of a transmission that won’t shift correctly, bangs into gear, or has left you stranded in limp mode, 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 wreak havoc on a perfectly good vehicle. This T42 TCM, part number 24252114, is the definitive solution for your 2006 Trailblazer EXT TCM issues and a wide range of other GM cars, trucks, and SUVs equipped with 4-speed automatic transmissions like the 4L60E, 4L65E, and 4L70E.
The TCM is the brain of your automatic transmission, responsible for executing every shift command, managing torque converter lockup for fuel efficiency, and monitoring the system for faults. When it fails, the symptoms are impossible to ignore. This replacement module is meticulously prepared and VIN-programmed with the latest GM software, ensuring it communicates flawlessly with your vehicle’s other computers right out of the box. No expensive trips to the dealer for programming are necessary.
Case Study: A Tricky Diagnosis
I remember a 2006 Trailblazer EXT that came into my shop with a classic complaint: intermittent harsh 1-2 shifts and occasionally getting stuck in 3rd gear, but only after driving for 20+ minutes. The owner had already replaced a shift solenoid with no luck. We scanned it and found a generic P0700 code. After checking the wiring and fluid, we focused on the TCM. These T42 modules are known to develop internal faults from heat cycles over the years. We swapped in a pre-programmed module, and the problem vanished instantly. The customer was thrilled to have their reliable daily driver back without a massive repair bill.
Is Your Trailblazer Showing These Signs?
A faulty TCM can manifest in several ways. If you’re experiencing any of the following, this module is likely the solution you need:
- ✔ Harsh, delayed, or erratic gear shifts that make driving uncomfortable.
- ✔ The vehicle is stuck in a single gear (often called “limp mode”) and won’t shift up or down.
- ✔ Check Engine Light or Transmission Warning Light is illuminated on your dash.
- ✔ Diagnostic Trouble Codes (DTCs) are stored, such as P0700 (Transmission Control System Malfunction), P0750-P0758 (Shift Solenoid Faults), or other transmission-related codes.
- ✔ A noticeable drop in fuel economy due to inefficient shifting.
- ✔ No communication with the TCM when using a diagnostic scan tool.
A Straightforward Guide to Installation
Replacing your 2006 Trailblazer EXT TCM is a job most DIYers can handle in their own garage in under 30 minutes. The location varies slightly by model, but it’s always accessible in the engine bay.
- Safety First: Disconnect the negative terminal from your vehicle’s battery to prevent any electrical shorts and to help reset the onboard systems.
- Locate the Module: On your Trailblazer EXT, the TCM is typically found in the left-hand (driver’s side) engine compartment. On other models, it might be next to the battery or under the air cleaner box.
- Disconnect and Remove: Carefully unplug the electrical connectors. They have locking tabs that need to be released. Then, unbolt the module from its mounting bracket.
- Install the New Module: Bolt the new, pre-programmed TCM into place and securely reconnect the electrical connectors. You should hear a click as they lock.
- Final Steps: Reconnect the battery terminal. While the module is plug-and-play, it’s good practice to use a basic scan tool to clear any lingering fault codes from the system’s memory. Start the vehicle and enjoy your smooth-shifting transmission!
Verified Vehicle Compatibility
This module, interchangeable with part numbers like 24234503, 24230461, and 24256960, is a direct-fit replacement for a vast range of GM vehicles. While this is not an exhaustive list, it fits many popular models including:
- ✔ Chevrolet: Trailblazer (8 cyl), Trailblazer EXT (8 cyl), Tahoe, Silverado 1500/2500, Suburban, Express Van, Impala, Cobalt, HHR
- ✔ GMC: Envoy / Envoy XL (8 cyl), Sierra 1500/2500, Yukon / Yukon XL, Savana Van, Canyon
- ✔ Buick: Rainier, LaCrosse, Lucerne
- ✔ Cadillac: DTS
- ✔ Pontiac: G6, Grand Prix
- ✔ Saturn: Vue, Aura, Ion
- ✔ Hummer: H3
- ✔ Saab: 9-7X
Please verify the part number and check the detailed fitment list to ensure this is the correct part for your specific vehicle and options.
No. This module arrives at your door pre-programmed to your vehicle’s specific VIN. This makes the installation a simple plug-and-play process, saving you hundreds of dollars and the hassle of a dealership appointment.
Basic hand tools are all that’s required. Typically, you’ll just need a socket wrench to disconnect the battery terminal and unbolt the module. No special diagnostic equipment is needed for the installation itself.
A P0700 code is a general fault code indicating the TCM has detected a problem. In many cases, a failing TCM is the root cause. Replacing it with this quality part is a very common and effective fix for this and related transmission codes.
No, there is no core charge. You can keep your old part or dispose of it at your convenience without the need to send it back to us.
We stand behind our products. This transmission control module comes with a one-year warranty, giving you peace of mind with your purchase.