If you’re dealing with the frustration of a transmission that won’t shift correctly, warning lights on the dash, or a vehicle stuck in limp mode, you’re not alone. As a technician with over two decades of experience under the hood, I’ve seen countless GM trucks and SUVs, including the dependable Yukon XL, sidelined by a failed Transmission Control Module (TCM). The TCM is the electronic brain of your automatic transmission, and when it fails, it can cause a cascade of problems that feel overwhelming. This is the definitive, hassle-free solution to get your truck back to operating smoothly and reliably.
This T42 TCM, corresponding to part number 24240449, is the exact component you need. The most significant benefit we offer is the complimentary VIN programming. Before this module ships, we flash it with the latest GM software calibrated specifically to your 2007-2008 Yukon XL 1500. This means you can skip the expensive and time-consuming trip to the dealership for programming. It arrives at your door ready for a true plug-and-play installation, restoring the crisp, predictable shifting you expect from your vehicle.
Is Your Yukon Exhibiting These Telltale Signs?
A faulty TCM can manifest in several ways. From my experience in the shop, these are the most common symptoms customers report before we diagnose a bad module. If you’re noticing any of these, a failing TCM is a very likely culprit.
- ✔ Harsh, banging shifts or delayed gear engagement.
- ✔ The vehicle is stuck in a single gear (often 2nd or 3rd), a condition known as “limp mode.”
- ✔ An illuminated Check Engine Light or Transmission Warning Light with Diagnostic Trouble Codes (DTCs) such as P0700 (Transmission Control System Malfunction), P0750-P0758 (Shift Solenoid errors), or other transmission-related codes.
- ✔ Failure to upshift or downshift, leading to poor acceleration and terrible fuel economy.
- ✔ Intermittent loss of communication with the TCM, causing unpredictable behavior.
A Technician’s Notebook
I recently had a 2008 Yukon XL 1500 in my bay with a classic complaint: erratic shifting and a P0700 code. The owner had already replaced two shift solenoids based on a generic code reader’s suggestion, but the problem persisted. This is a common and costly misstep. The P0700 code is a general fault code, simply meaning the TCM has detected a problem and requested the check engine light. The real issue was internal to the TCM itself; its processor was failing under heat, causing it to send faulty commands to perfectly good solenoids. After confirming power and ground to the module were solid, we installed one of our VIN-programmed TCMs. The problem was solved instantly, and all codes were cleared. This highlights why shotgunning parts doesn’t work—addressing the root cause with a quality module is the only real fix.
The Smart Solution for Your Transmission
Choosing this module is about more than just replacing a part; it’s about making a smart, long-term repair.
- ✔ VIN-Programmed for Your Truck: We handle the complex programming for you. This ensures perfect communication between the engine and transmission for optimal performance and fuel efficiency, right out of the box.
- ✔ Restore Drivability: This module directly controls shift pressure, torque converter lockup, and shift timing, eliminating harshness and restoring a smooth ride.
- ✔ OEM-Standard Quality: Built to meet or exceed original equipment specifications for durability and longevity. We back it with a one-year warranty for your peace of mind.
- ✔ No Core Charge: Keep your old part. There are no hidden fees or complicated core return processes to worry about.
DIY-Friendly Installation in Under 30 Minutes
Replacing the 2007-2008 Yukon XL 1500 TCM is a straightforward job that most DIYers can handle with basic tools. On your Yukon, it’s typically located in the engine bay, right next to the battery.
- Safety First: Disconnect the negative terminal from your vehicle’s battery to prevent any electrical shorts and to help reset the system.
- Locate the TCM: Find the module mounted next to the battery in the engine compartment. It will have several large electrical connectors attached.
- Disconnect and Remove: Carefully unclip the wiring harness connectors. Then, unbolt the module from its mounting bracket and remove it from the vehicle.
- Install the New Module: Bolt the new, pre-programmed TCM into place. Securely reconnect the wiring harnesses, ensuring they click into place.
- Final Steps: Reconnect the negative battery terminal. While the module is plug-and-play, it’s always best practice to use a basic scan tool to clear any stored historical fault codes from the vehicle’s memory. Start the vehicle and enjoy your smooth-shifting transmission!
Verified Fitment for These GM Models
While this page focuses on the 2007-2008 Yukon XL 1500 TCM, this module, part number 24240449, is compatible with a wide range of General Motors vehicles equipped with 4-speed automatic transmissions like the 4L60E, 4L65E, and 4L70E. Please verify your specific model and year from the list below.
Partial Fitment List:
- Chevrolet Tahoe, Silverado 1500, Suburban 1500, Avalanche (2007-2009)
- GMC Yukon, Sierra 1500 (2007-2013)
- Chevrolet Express / GMC Savana Vans (2006-2014)
- Hummer H3 (2008-2010)
- Chevrolet Colorado / GMC Canyon (2008-2012)
- And many more Buick, Cadillac, Pontiac, and Saturn models.
Frequently Asked Questions
Do I need to take my vehicle to the dealer after installing this TCM?
No. This module comes fully programmed to your vehicle’s VIN. It is a plug-and-play installation that does not require any additional dealership programming, saving you time and money.
Where is the TCM located on my 2007 Yukon XL 1500?
On the 2007-2008 GMC Yukon XL 1500, the Transmission Control Module (TCM) is conveniently located in the engine compartment, mounted right next to the battery.
Will this fix a P0700 trouble code?
In many cases, yes. A P0700 code indicates the TCM has detected a fault. If the TCM itself is the source of the electrical or processing failure, replacing it with this new module will resolve the root cause and allow the code to be cleared.
Is this part the same as an ECM or PCM?
No. This is the Transmission Control Module (TCM), which exclusively manages the automatic transmission. The Engine Control Module (ECM) or Powertrain Control Module (PCM) manages engine functions and, in some vehicles, may integrate transmission control. This T42 is a separate, dedicated transmission computer.
What if I order the wrong part?
We encourage you to verify fitment using your vehicle’s year, make, and model, or by matching the part number 24240449. If you have any doubts, our expert support team is here to help you confirm the correct part for your vehicle before you order.