If your 2006-2007 Buick Rainier is suffering from harsh shifting, getting stuck in gear, or throwing transmission codes, you’ve come to the right place. As a technician with over two decades of experience under the hood, I’ve seen countless GM vehicles sidelined by a faulty Transmission Control Module (TCM). The T42 module, specifically, is the electronic brain of your automatic transmission, and when it fails, it can cause a cascade of frustrating and potentially damaging issues. This isn’t just a part; it’s the solution to restoring the smooth, reliable performance your Rainier was built for.
This OEM-quality T42 TCM, part number 24239224, is the definitive fix for these common problems. The biggest hurdle for most DIYers and even professional shops is the programming. A blank module from the dealership requires expensive, specialized tools to flash it to your vehicle. We eliminate that step entirely. By providing your vehicle’s VIN at checkout, we program the module with the latest GM software updates specifically for your Rainier. This means it arrives at your door ready for a true plug-and-play installation, saving you hundreds in dealership fees and hours of downtime.
A Technician’s Notebook: The Intermittent Gremlin
I remember a 2007 Rainier that came into the shop with a complaint that stumped two other mechanics. The owner said it would randomly refuse to shift out of 2nd gear, but only after driving for 20+ minutes. By the time he got to a shop, the problem would disappear. We checked fluid levels, solenoids, and wiring—all perfect. On a hunch, we monitored the TCM data stream on a long test drive. Sure enough, as the engine bay heated up, the TCM started sending erratic signals. Heat soak was causing a micro-fracture on the circuit board to expand, breaking the connection. A new, pre-programmed TCM fixed it instantly. It’s a classic failure mode for these modules.
Is Your Buick Rainier Showing These Telltale Signs?
A failing TCM doesn’t always mean a complete transmission failure. Often, the signs are electronic. If you’re experiencing any of the following, a faulty 2006-2007 Rainier Transmission Module is the likely culprit:
- ✔ Harsh, jerky, or delayed gear shifts.
- ✔ Vehicle is stuck in “limp mode” (usually 2nd or 3rd gear).
- ✔ The Check Engine Light or a transmission-specific warning light is on.
- ✔ Diagnostic Trouble Codes (DTCs) are present, such as P0700 (Transmission Control System Malfunction) or P0750-series solenoid codes.
- ✔ Inconsistent upshifting or downshifting.
- ✔ A noticeable drop in fuel economy.
- ✔ Complete loss of communication with the transmission module.
Your 30-Minute Path to a Smooth Ride
You don’t need to be a master mechanic to replace this module. The process is straightforward and can be completed in your driveway with basic hand tools. For the 2006-2007 Rainier, the TCM is typically located in the engine compartment for easy access.
- Safety First: Disconnect the negative terminal from your vehicle’s battery to prevent any electrical shorts and to help reset the system.
- Locate the Module: On the Rainier, you’ll typically find the TCM in the engine compartment. Check common locations like near the air cleaner box or on the driver’s side. It’s a silver box with electrical connectors.
- 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 module into place. Reconnect the wiring harnesses, ensuring they click securely into place.
- Reconnect and Verify: Reconnect the battery terminal. Start the vehicle and let it idle for a moment. Use a basic OBD2 scan tool to clear any stored fault codes. Take a test drive to confirm that shifting is smooth and responsive.
Verified Fitment Beyond the Buick Rainier
While this is the perfect solution for your 2006-2007 Rainier Transmission Module replacement, its T42 architecture was used across a massive range of General Motors vehicles. It is a direct replacement for multiple part numbers, including 24252114, 24234503, 24239224, and 24256960. It is compatible with popular models like:
- ✔ Chevrolet Silverado, Tahoe, Impala, Cobalt, HHR
- ✔ GMC Sierra, Yukon, Savana, Envoy
- ✔ Cadillac DTS
- ✔ Pontiac G6, Grand Prix
- ✔ Saturn Vue, Aura, Ion
- ✔ Hummer H3 and Saab 9-7X
Frequently Asked Questions
Do I need to program this module after I receive it?
No. This module is fully pre-programmed to your vehicle’s VIN before shipping. It is ready for installation right out of the box, with no need for a trip to the dealership.
How do I provide my VIN number?
You can enter your Vehicle Identification Number (VIN) during the checkout process. This ensures we load the correct software for your specific vehicle configuration.
Is a core charge required for my old part?
No, there is no core charge. You can keep your old module or dispose of it without the hassle of returning it.
What is the warranty on this part?
This transmission control module comes with a one-year warranty, giving you peace of mind and confidence in your repair.
Will this fix a P0700 code?
A P0700 code is a general transmission fault request from the TCM to the Engine Control Module (ECM) to turn on the check engine light. While a failing TCM is a very common cause, this code indicates a fault has been stored within the TCM. Replacing the module often resolves the root cause of the P0700 and any associated specific codes (like for solenoids or sensors).