If you’re dealing with the frustration of a transmission that won’t shift correctly, is stuck in limp mode, or throws a check engine light on your 2006-2007 Buick Rainier, you’ve come to the right place. As a technician with over two decades of experience under the hood, I’ve seen countless drivers worry that they need a full transmission rebuild when the real culprit is a faulty Transmission Control Module (TCM). This VIN-programmed T42 TCM is the definitive, reliable solution to restore your vehicle’s performance and get you back on the road with confidence.
The TCM is the brain of your automatic transmission, responsible for executing every gear change with precision. When it fails, communication between the engine and transmission breaks down, leading to the jarring shifts and poor performance you’re likely experiencing. This replacement module, equivalent to OEM part number 24240400, is meticulously programmed to your vehicle’s specific VIN before it ships. This means no expensive trips to the dealership for programming—it’s a true plug-and-play fix that a DIYer can handle in their own driveway.
A Technician’s Notebook
I remember a 2007 Rainier that came into the shop with classic symptoms: it would slam into gear from a stop and refused to shift past 3rd gear on the highway. The owner was convinced his transmission was shot. After a quick scan, I saw a P0700 (Transmission Control System Malfunction) and a few solenoid circuit codes. Instead of quoting a multi-thousand dollar transmission job, we started with the brain. We installed a VIN-programmed 2006-2007 Rainier TCM, and within 30 minutes, the vehicle was shifting as smoothly as the day it left the factory. It’s a common failure point, and this part is the most direct and effective fix.
Is Your Buick Exhibiting These Transmission Problems?
A failing TCM can manifest in several ways. If you notice any of the following, it’s a strong indicator that your module needs replacement:
- ✔ Harsh, erratic, or delayed gear shifts.
- ✔ Vehicle is stuck in one gear (often called “limp mode”).
- ✔ Check Engine Light or Transmission Warning Light is illuminated.
- ✔ Diagnostic Trouble Codes (DTCs) such as P0700, P0750, or other solenoid-related faults are present.
- ✔ A sudden drop in fuel economy.
- ✔ The transmission feels like it’s slipping between gears.
Your Straightforward 30-Minute Installation Guide
You don’t need to be a master mechanic to install this part. The process is simple and requires only basic hand tools. For the Buick Rainier, the TCM is typically located in the engine compartment. Follow these steps for a successful installation:
- 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: On the 2006-2007 Rainier, you’ll find the TCM in the engine compartment. It’s a silver box with electrical connectors.
- Disconnect and Remove: Carefully unplug the electrical harness connectors from the old TCM. Then, unbolt the module from its mounting bracket and remove it from the vehicle.
- Install the New Module: Mount your new, VIN-programmed TCM onto the bracket and securely tighten the bolts. Reconnect the electrical harnesses, ensuring they click into place.
- Final Steps: Reconnect the negative battery terminal. While the system often resets, it’s best practice to use a basic OBD-II scan tool to clear any stored transmission codes. Start the vehicle and take it for a test drive to confirm the shifting issues are resolved.
Verified Fitment for Your Vehicle
This T42 Transmission Control Module is a direct-fit replacement for the 2006-2007 Rainier TCM and is also compatible with a wide array of other General Motors vehicles that use the 4L60E, 4L65E, and 4L70E transmissions. It is interchangeable with part numbers 24252114, 24234503, 24230461, and more. While this is the correct part for the models listed below, always verify your part number before ordering.
- Buick Rainier: 2006-2007
- Chevrolet Trailblazer (8 cylinder): 2006-2009
- GMC Envoy (8 cylinder): 2006-2009
- Hummer H3: 2008-2010
- Saab 9-7X: 2006-2009
- Chevrolet Silverado & GMC Sierra 1500/2500: 2007-2013 (Check specific options)
- Chevrolet Tahoe/Suburban & GMC Yukon: 2007-2009
- And many other GM cars, trucks, and SUVs from 2006-2014.
Frequently Asked Questions
What does ‘VIN Programmed’ mean for me?
It means we load your vehicle’s specific Vehicle Identification Number (VIN) and the latest GM software onto the module before shipping. This ensures it communicates perfectly with your vehicle’s other computers right out of the box, eliminating the need for dealer-level programming.
Is this a difficult part for a DIYer to install?
Not at all. This is one of the more straightforward electronic repairs. With basic hand tools and our guide, most people can complete the job in under 30 minutes. The key is simply disconnecting the battery and swapping the modules.
Will this part fix a P0700 trouble code?
A P0700 code is a general fault code indicating the TCM has detected a problem. While this module often resolves the root cause (like internal circuit failure), you should have the specific transmission codes (e.g., P0751, P0756) read to confirm the diagnosis. In many cases, replacing a faulty TCM is the correct fix.
Do I need to send my old part back?
No, there is no core charge for this part. You can keep your old module or recycle it locally, making the process completely hassle-free.