Restore Your Buick’s Shifting Performance
If your 2006-2007 Buick Rainier is suffering from harsh shifting, getting stuck in gear, or throwing transmission codes, you’re not alone. In my 20+ years as a technician, I’ve seen countless GM vehicles sidelined by a faulty Transmission Control Module (TCM). The internal electronics fail from heat and vibration, leading to erratic communication with the transmission’s solenoids. This isn’t just an annoyance—it can cause premature wear on your transmission’s mechanical parts. The solution is a reliable, correctly programmed replacement.
This T42 Transmission Control Module is the definitive fix for your shifting woes. We take the guesswork and dealer hassle out of the equation by pre-programming it to your Rainier’s specific Vehicle Identification Number (VIN). This ensures it works seamlessly with your vehicle’s systems right out of the box. You’re not just buying a part; you’re buying a complete solution that restores the smooth, predictable performance you expect from your Buick. This is the exact type of repair we perform in our shop to get customers back on the road with confidence.
Case Study: A Tricky Diagnosis
A customer brought in a 2007 Buick Rainier with classic signs of a failing transmission—banging into gear and refusing to upshift past 3rd. They were convinced they needed a costly transmission rebuild. After connecting my scan tool, I saw a P0752 (Shift Solenoid A Stuck On) code, but the solenoid itself tested fine. Experience pointed me to the TCM. The module’s internal driver for that solenoid circuit had failed. We installed a VIN-programmed 2006-2007 Rainier Transmission Module, cleared the codes, and the vehicle shifted perfectly. It saved the customer thousands and fixed the root cause, not just the symptom.
Is Your Rainier Exhibiting These Telltale Signs?
- ✔ Harsh, delayed, or erratic gear changes that slam or slip.
- ✔ Vehicle is stuck in “limp mode,” often refusing to shift out of 2nd or 3rd gear.
- ✔ The Check Engine Light or Transmission Warning Light is on.
- ✔ Diagnostic Trouble Codes (DTCs) are present, such as P0700, P0750, P0751, P0752, or other solenoid-related faults.
- ✔ A noticeable drop in fuel economy due to inefficient shifting.
- ✔ Complete loss of communication with the TCM, leading to a no-shift condition.
A Straightforward Guide to Installation
Replacing the TCM on your Rainier is a job most DIYers can handle in under 30 minutes with basic tools. The module is 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 electrical shorts and help reset the system.
- Locate the Module: On the 2006-2007 Rainier, the TCM is typically found in the engine compartment. Check common GM locations like next to the battery or under the air cleaner box.
- Disconnect and Remove: Carefully unplug the electrical connectors. They have locking tabs that need to be released. Then, unbolt the old module from its mounting bracket.
- Install the New Module: Bolt the new, pre-programmed module into place. Securely reconnect the electrical harnesses, making sure they click into place.
- Final Steps: Reconnect the battery terminal. Start the vehicle and use a standard OBD2 scan tool to clear any stored transmission codes. Take a test drive to confirm smooth shifting.
Verified Vehicle Compatibility
This module is a direct-fit replacement for the 2006-2007 Rainier Transmission Module. While it is guaranteed for your Buick, it also serves as a replacement for a wide range of other GM vehicles that use the T42 TCM platform, including many Chevrolet, GMC, Pontiac, and Saturn models. It is interchangeable with part numbers: 24252114, 24234503, 24230461, 24234274, 24235340, 24235754, 24238856, 24239224, 24239926, 24240400, and more.
Frequently Asked Questions
What does “VIN Programmed” actually mean?
It means we load your vehicle’s unique 17-digit VIN into the module before shipping. This ensures the TCM has the correct software and calibrations for your Rainier’s specific engine, transmission, and options, making it a true plug-and-play part without needing a dealer visit.
Do I need any special tools for this installation?
No special tools are required. Basic hand tools like a socket set will be sufficient for removing the mounting bolts and disconnecting the battery. An OBD2 scanner is recommended to clear codes post-installation, but not strictly necessary for the module to function.
Will this fix a P0700 trouble code?
A P0700 code is a generic fault request from the TCM to the Engine Control Module (ECM) to turn on the check engine light. A failing TCM is a very common cause of this code. Replacing the module will often resolve the P0700 and any other specific transmission codes that were present.
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 at your convenience, saving you the hassle and expense of shipping it back.
My original part number isn’t 24239926, but it’s on the interchange list. Will this work?
Yes. GM often uses multiple part numbers for the same component over its production life. As long as your part number is on our interchange list, this module is the correct, updated replacement for your vehicle.