Restore Flawless Shifting to Your GM Vehicle
If your 2006 Chevrolet Trailblazer EXT is suffering from harsh shifts, getting stuck in gear, or throwing transmission codes, you’ve likely pinpointed the culprit: a failing Transmission Control Module (TCM). As a technician with over two decades of experience under the hood, I’ve seen countless GM vehicles crippled by faulty T42 modules. The symptoms can be maddening, from unpredictable gear changes to a complete loss of communication that leaves you stranded. This isn’t just an annoyance; it’s a critical failure that impacts your vehicle’s performance, safety, and fuel economy.
This replacement T42 TCM, part number 24234274, is the definitive solution. The most significant benefit is that it arrives at your door expertly programmed to your vehicle’s specific VIN. This eliminates the need for expensive dealership visits and specialized scan tools for programming. It’s a direct-fit, plug-and-play repair that restores the precise electronic control your automatic transmission (like the 4L60E, 4L65E, or 4L70E) requires for smooth, efficient operation. By replacing your old module, you’re not just clearing codes; you’re providing a stable, reliable brain for your transmission, protecting it from the potential damage caused by erratic electronic signals.
From the Diagnostic Bay: The Ghost in the Transmission
A customer brought in a 2008 Sierra with a classic complaint: ‘It bangs into gear and sometimes won’t shift past 2nd.’ His local shop had already replaced two shift solenoids based on the DTCs, but the problem persisted intermittently. After connecting my scanner, I saw the tell-tale signs: U-codes indicating lost communication with the TCM, alongside the solenoid codes. The issue wasn’t the solenoids themselves, but the module failing to command them correctly. We installed one of our VIN-programmed T42 modules. The swap took less than 20 minutes. After a quick battery disconnect to reset adaptations, the truck shifted like it just rolled off the factory floor. This is a prime example of how a faulty 2006 Trailblazer EXT TCM can mimic other failures, making a direct replacement the most effective repair.
Is Your Trailblazer Showing These Symptoms?
A failing TCM can manifest in several ways. If you’re experiencing any of the following, it’s a strong indicator that your module needs replacement:
- âś” Harsh, slamming, or delayed gear engagement.
- âś” Vehicle is stuck in “limp mode” (usually 2nd or 3rd gear).
- âś” Check Engine Light or Transmission Warning Light is on.
- âś” Diagnostic Trouble Codes (DTCs) are present, especially P0700, P0750-P0758, or other solenoid-related faults.
- âś” Inability to upshift or downshift correctly.
- âś” Noticeably poor fuel mileage and potential transmission overheating.
- âś” Complete loss of communication with the transmission module.
A Straightforward Guide to Installation
One of the best features of this module is its simple, DIY-friendly installation. No complex procedures or dealer visits are required. For your 2006 Trailblazer EXT TCM, the module 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 electrical shorts and help reset the system.
- Locate the Old TCM: Find the module in the engine bay. It will have several large electrical connectors attached to it.
- Disconnect and Remove: Carefully unplug the wiring harness connectors. Then, unbolt the module from its mounting bracket.
- Install the New Module: Bolt the new, pre-programmed TCM into place. Securely reconnect the wiring harnesses, ensuring they click into place.
- Reconnect Power: Re-attach the negative battery terminal.
- Final Check: Start the vehicle. The warning lights should be off. While not always necessary, using a basic OBD2 scanner to clear any stored historical codes is good practice. Take the vehicle for a test drive to confirm smooth shifting.
Verified Vehicle Compatibility
This T42 TCM is a direct replacement for a wide range of General Motors vehicles. While this page is focused on the 2006 Trailblazer EXT TCM, it is also compatible with the following models and locations. Always verify your part number (24234274) or one of its interchanges (24252114, 24234503, etc.) for a guaranteed fit.
- Chevrolet: Silverado, Tahoe, Suburban, Avalanche, Express, Colorado, Impala, Monte Carlo, HHR, Cobalt, Malibu
- GMC: Sierra, Yukon, Savana, Canyon, Envoy
- Buick: LaCrosse, Lucerne, Allure, Rainier, Rendezvous
- Cadillac: DTS
- Pontiac: G6, G5, Grand Prix, Pursuit
- Saturn: Vue, Aura, Ion
- Hummer: H3
- Saab: 9-7X
Frequently Asked Questions
Is this part difficult to install for a DIYer?
Not at all. Since it comes pre-programmed to your VIN, the installation is a simple plug-and-play process. It typically involves disconnecting the battery, unplugging the old module, bolting in the new one, and reconnecting everything. Most people can do it in under 30 minutes with basic hand tools.
What does ‘VIN Programmed’ actually mean?
It means we load your vehicle’s unique Vehicle Identification Number (VIN) and the latest GM software onto the module before we ship it. This ensures it communicates perfectly with your vehicle’s engine computer and other systems right out of the box, avoiding the need for a trip to the dealership for costly programming.
Will this fix a P0700 trouble code?
A P0700 code is a general fault request from the TCM to the main engine computer (ECM) to turn on the check engine light. While this module often resolves the root cause of the P0700 (like a bad solenoid circuit inside the TCM), you should always diagnose the specific codes that accompany it. In many cases where the TCM itself is faulty, this part is the correct fix.
Is there a core charge for my old part?
No, there is no core charge. You can keep your old part or dispose of it without the hassle of needing to send it back to us.
What is the warranty on this TCM?
This Transmission Control Module comes with a one-year warranty, giving you peace of mind and confidence in your repair.