End Your Buick Rainier’s Transmission Headaches for Good
If you’re dealing with the frustration of a 2006-2007 Buick Rainier that shifts harshly, gets stuck in gear, or throws confusing 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 failing Transmission Control Module (TCM). The TCM is the brain of your automatic transmission, and when it starts to fail, it can cause a cascade of problems that feel like a major mechanical failure but are often just a faulty electronic component. This T42 series TCM, part number 24243921, is the definitive solution, pre-programmed to your vehicle’s VIN for a hassle-free, direct-fit replacement.
From the Diagnostic Bay: The Rainier That Wouldn’t Shift
I remember a customer bringing in a ’07 Rainier with classic symptoms: intermittent ‘slamming’ into gear and occasionally getting stuck in 3rd gear (limp mode). They had already spent a small fortune at another shop that replaced two shift solenoids, with no improvement. The real culprit? The original TCM had developed internal micro-fractures from years of heat cycles in the engine bay. A quick scan showed a P0700 code, but no specific solenoid faults. We installed one of our VIN-programmed T42 modules, and in less than an hour of shop time, the Rainier was shifting like it just rolled off the assembly line. It’s a textbook example of how replacing the right electronic part can save you from unnecessary and expensive mechanical repairs.
Is Your Rainier Showing These Telltale Signs?
A failing TCM doesn’t always mean a complete transmission failure. Often, the signs are electronic in nature. If you’re experiencing any of the following, a faulty module is the likely cause:
- ✔ Harsh, jerky, or delayed gear shifts.
- ✔ The vehicle is stuck in a single gear (often called ‘limp mode’).
- ✔ Check Engine Light or Transmission Warning Light is on.
- ✔ Diagnostic Trouble Codes (DTCs) are present, especially a P0700 (Transmission Control System Malfunction) or various solenoid codes (P0750-P0799).
- ✔ Inconsistent or no communication with the TCM via a scan tool.
- ✔ Poor fuel economy and a feeling of sluggish performance.
Your 30-Minute Path to Smoother Shifting
One of the best features of this module is that it’s designed for a straightforward installation that a confident DIYer or any professional mechanic can complete quickly. No need for a trip to the dealer for expensive programming.
- 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 2006-2007 Buick Rainier, the TCM is typically found in the engine compartment. Check for a silver box with electrical connectors.
- Swap the Part: Carefully unplug the wiring harness connectors. Unbolt the old TCM from its mounting bracket and set it aside. Bolt the new module into place and securely reconnect the wiring harnesses.
- Final Steps: Reconnect the battery terminal. Start the vehicle and let it idle for a few minutes. While not always necessary, using a basic OBD2 scan tool to clear any stored fault codes is a best practice.
Verified Fitment for Your Vehicle
This module is a direct replacement for part number 24243921 and is guaranteed to fit your 2006-2007 Buick Rainier. It also fits a wide range of other GM vehicles that use the T42 TCM. Below is a partial list of compatible models:
- Buick Rainier: 2006-2007
- Chevrolet Trailblazer: 2006-2009 (V8 models)
- GMC Envoy / Envoy XL: 2006-2009 (V8 models)
- Saab 9-7X: 2006-2009
- Hummer H3: 2008-2010
- …and many other GM cars, trucks, and SUVs from 2006-2014. Please verify your part number for a perfect match.
Do I need to get this TCM programmed by a dealer?
Do I need to get this TCM programmed by a dealer?
No. We handle all the programming for you before shipment. Simply provide your vehicle’s VIN during checkout, and the module will arrive ready for plug-and-play installation.
Is there a core charge for my old part?
No, there is no core charge. You can keep your old module or dispose of it without the hassle of sending it back.
What tools are required for installation?
Basic hand tools are all that’s needed. Typically, a simple socket set to remove the mounting bolts and a flathead screwdriver to help release the connector tabs are sufficient. The entire process usually takes less than 30 minutes.
What if this doesn’t fix my problem?
While this part corrects the most common cause of the symptoms listed, we stand by our products. This module comes with a one-year warranty. If you have any diagnostic questions, our expert support team is here to help you confirm the TCM is the right fix for your vehicle.