End Erratic Shifting and Restore Your GM’s Performance
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’re not alone. As a technician with over two decades of experience, I’ve seen countless GM vehicles sidelined by a faulty Transmission Control Module (TCM). The T42 module, the electronic brain of your automatic transmission, is a common failure point. When it goes, it can cause a cascade of problems, from a flashing check engine light to a complete loss of drivability. This isn’t just an annoyance; it’s a safety concern.
This OEM-quality T42 TCM is the definitive solution for your 2006 Trailblazer EXT TCM issues and a wide range of other GM cars, trucks, and SUVs. What sets our modules apart is the critical VIN programming service we perform before shipping. We load your vehicle’s specific VIN and the latest GM software updates onto the module, making it a true plug-and-play part. This eliminates the need for an expensive trip to the dealership for programming, saving you hundreds of dollars and significant downtime. You get a reliable part that’s ready to install right out of the box.
From the Diagnostic Bay: The Case of the Slipping Sierra
A customer brought in his 2008 Sierra 1500 with classic symptoms: harsh 1-2 shifts and intermittent ‘Transmission Hot’ warnings, even on cool days. He’d already replaced a shift solenoid with no luck. A quick scan showed a P0752 (Shift Solenoid A Stuck On) and the telltale P0700 (Transmission Control System Malfunction). After 20 years in the business, I know that when solenoid codes return after a replacement, the driver circuit in the TCM is often the real culprit. Heat cycles and vibration cause internal solder joints to fail. We installed one of our VIN-programmed T42 modules, cleared the codes, and the truck was shifting like new in under an hour. It’s a textbook repair we’ve done hundreds of times.
Is Your GM Vehicle Showing These Telltale Signs?
A failing TCM will give you clear warnings. If you’re experiencing any of the following, it’s highly likely your module needs replacement:
- âś” Unpredictable, harsh, or delayed gear shifts.
- âś” Vehicle is stuck in one gear (often called “limp mode”).
- âś” Check Engine Light or Transmission Warning Light is on.
- âś” Diagnostic Trouble Codes (DTCs) are present, such as P0700, P0750, P0751, P0752, or other solenoid-related faults.
- âś” Poor acceleration and a noticeable drop in fuel economy.
- âś” Complete failure to shift or engage a gear.
A Straightforward Guide to Your TCM Installation
One of the best features of this part is how simple the installation is for a DIYer or a professional mechanic. You can have your vehicle back to normal in about 30 minutes with basic hand tools.
- Safety First: Always disconnect the negative terminal on your vehicle’s battery before starting any electrical work.
- Locate the Module: On your 2006 Trailblazer EXT, the TCM is typically found in the engine compartment on the left-hand (driver’s) side. On other GM models, it could be next to the battery, under the air cleaner box, or on a frame rail. Check your specific model’s layout.
- Disconnect and Remove: Carefully unplug the electrical connectors. Press the release tabs firmly to avoid breaking them. Then, unbolt the module from its mounting bracket.
- Install the New TCM: Bolt the new, pre-programmed module into place and securely plug in the electrical connectors. You should hear a ‘click’ as they lock.
- Final Steps: Reconnect the battery terminal. Start the vehicle and let it idle for a minute. While the module is plug-and-play, it’s good practice to use a basic OBD2 scanner to clear any old stored codes from the vehicle’s memory.
Guaranteed Fitment for Your GM Vehicle
This module, also known by part number 24241806, is a direct replacement for a wide range of GM vehicles equipped with 4-speed automatic transmissions like the 4L60E, 4L65E, and 4L70E. Please verify your model and year below:
Fits Models Including:
- Chevrolet: Trailblazer (06-09), Silverado (07-13), Tahoe (07-09), Impala (06-11), Cobalt (06-10), HHR (06-11), Express Van (06-14)
- GMC: Envoy (06-09), Sierra (07-13), Yukon (07-09), Savana Van (06-14), Canyon (08-12)
- Buick: LaCrosse (06-09), Lucerne (06-11), Rainier (06-07)
- Pontiac: G6 (06-10), Grand Prix (06-08)
- Cadillac: DTS (06-11)
- Hummer: H3 (08-10)
- And many more… This part interchanges with 24252114, 24234503, 24240400, and others.
Frequently Asked Questions
Do I need to do any programming after I install this?
No. This module arrives pre-programmed to your vehicle’s specific VIN. It’s a true plug-and-play installation, saving you a trip to the dealership.
Will this fix my check engine light for code P0700?
Yes, in most cases. P0700 is a generic code indicating the TCM has detected a fault. If the root cause is a failing TCM, replacing it with this programmed unit will resolve the code and the underlying issue.
What is the warranty on this part?
We stand behind our quality with a one-year, hassle-free warranty. This ensures you’re getting a reliable part built to meet or exceed OEM specifications for long-lasting performance.
Is there a core charge for my old part?
No, there is no core charge required. You can keep your old part or dispose of it at your convenience, making the transaction simple and straightforward.
How do I provide my VIN for programming?
You will be prompted to enter your vehicle’s 17-digit VIN during the checkout process. Please double-check it for accuracy to ensure perfect programming for your specific vehicle.