If you’re dealing with a 2006-2009 Chevrolet Trailblazer that’s shifting erratically, getting stuck in gear, or throwing transmission codes, you’ve likely pinpointed a faulty Transmission Control Module (TCM). As a technician with over two decades of experience, I’ve seen countless GM vehicles, especially those with the robust 4L60E and 4L65E transmissions, suffer from these exact issues. The TCM is the transmission’s brain, and when it fails, the symptoms can range from annoying to downright dangerous. This T42 TCM, part number 24240449, is the definitive, hassle-free solution.
What makes this part the smart choice for both seasoned mechanics and first-time DIYers is our pre-programming service. We flash the module with your Trailblazer’s specific Vehicle Identification Number (VIN) before it even leaves our facility. This means no expensive trips to the dealership for programming, no special scan tools required for setup—it’s a true plug-and-play fix. You’re not just buying a part; you’re buying a complete solution that restores the crisp, reliable shifting you expect from your vehicle.
From the Diagnostic Bay
A customer brought in his 2008 Trailblazer, complaining it was stuck in what felt like third gear (a classic limp mode symptom) and the check engine light was on. A quick scan revealed code P0700 (Transmission Control System Malfunction) and a P0758 for a shift solenoid B electrical fault. After verifying the solenoid’s wiring and resistance were good, I knew the problem was internal to the TCM—a common failure point. Instead of a costly and time-consuming dealer visit, we ordered one of these pre-programmed modules. The installation took less than 20 minutes, and after clearing the codes, the truck shifted perfectly on the test drive. The customer was back on the road the same day, having saved hundreds on dealer labor and programming fees.
Is Your Trailblazer Exhibiting These Symptoms?
A failing TCM can manifest in several ways. If you’re experiencing any of the following, a replacement is likely needed to prevent further damage to your transmission.
- ✔ Harsh, slamming shifts or delayed gear engagement.
- ✔ Vehicle is stuck in a single gear (limp mode) and won’t shift up or down.
- ✔ Check Engine Light or Transmission Warning Light is illuminated.
- ✔ Diagnostic Trouble Codes (DTCs) are present, such as P0700, P0750-series solenoid codes, or communication errors.
- ✔ A sudden drop in fuel economy or a feeling of lost power.
- ✔ The transmission seems to slip between gears or fails to engage drive or reverse intermittently.
A Straightforward Guide to Installation
Installing your new 2006-2009 Trailblazer TCM is a simple process that can be done with basic hand tools. For the Trailblazer, the TCM is typically located in the left-hand (driver’s side) engine compartment.
- Safety First: Disconnect the negative terminal from your vehicle’s battery to prevent any electrical shorts and to help reset the system.
- Locate the Old Module: Find the TCM in the LH engine compartment. It’s a silver box with electrical connectors.
- Disconnect and Remove: Carefully unplug the electrical harnesses. Then, unbolt the module from its mounting bracket.
- Install the New TCM: Mount your new, pre-programmed TCM in the same location and securely reconnect the electrical harnesses.
- Final Steps: Reconnect the battery terminal. Start the vehicle and use a basic scan tool to clear any stored DTCs if they haven’t cleared automatically. Your transmission is now ready for operation.
Verified Vehicle Compatibility
While this is the correct part for your 2006-2009 Trailblazer TCM repair, it also fits a wide range of other General Motors vehicles. Please verify your model and location notes below. This part is interchangeable with service numbers: 24252114, 24234503, 24230461, 24234274, 24235340, 24235754, 24238856, 24239224, 24239926, 24240400, 24241806, 24243901, 24243921, 24255280, 24256960, 24235732, 24235753, and YNXS.
Fitment Includes: TRAILBLAZER 06-09 (8 cylinder or 08-09 models, LH engine compartment), ENVOY 06-09, SILVERADO/SIERRA 1500/2500 07-13, TAHOE/YUKON 07-09, HHR 06-11, IMPALA 06-11, COBALT 06-10, HUMMER H3 08-10, and many more. Please check the detailed fitment list to confirm your specific application.
Frequently Asked Questions
What does a VIN-programmed TCM actually do?
VIN programming loads your vehicle’s specific software and calibrations onto the module before shipping. This ensures it communicates perfectly with your engine computer and other systems, controlling shift points, line pressure, and torque converter lockup exactly as the factory intended, without any additional setup.
Is this a difficult part to install myself?
Not at all. For most DIYers with basic tools, this is a job that takes less than 30 minutes. The module is easily accessible in the engine bay, and because it’s pre-programmed, the most complex part of the job (the software) is already done for you.
Will this fix my P0700 and P0753 codes?
If the fault lies within the TCM itself, yes. P0700 is a general transmission fault code, and codes like P0753 (Shift Solenoid ‘A’ Electrical) are often caused by a failed driver circuit inside the TCM. This module is designed to resolve these common electronic failures.
Do I need to send my old TCM back?
No, there is no core charge for this part. You can keep your old module or dispose of it responsibly without the hassle of returning a core.
How do I provide my VIN for programming?
After you place your order, you will be prompted to provide your vehicle’s 17-digit VIN. We cannot ship the part until we receive this information, as the programming is essential for the part to function.