End Your Buick’s Shifting Nightmares for Good
As a technician with over two decades of experience under the hood, I’ve seen countless drivers frustrated by transmissions that seem to have a mind of their own. If your 2006-2007 Buick Rainier is suffering from harsh shifts, getting stuck in gear, or throwing transmission codes, the problem is very often the Transmission Control Module (TCM). This isn’t just an annoyance; it’s a critical failure that impacts your vehicle’s performance, fuel economy, and safety. This T42 TCM, part number 24240400, is the definitive solution, arriving at your door pre-programmed to your vehicle’s specific VIN.
The TCM acts as the brain for your automatic transmission, controlling everything from shift points to torque converter lockup. When it fails, communication breaks down, leading to the erratic behavior you’re experiencing. Dealerships will often charge a premium for the part and then add on expensive programming fees. Our module eliminates that step entirely. By programming it with the latest GM software updates before it ships, we ensure it’s a true plug-and-play component. You get a reliable, OEM-spec part that restores the smooth, predictable performance your Rainier had when it left the factory.
Case Study: The Ghost in the Transmission
I once had a 2007 GMC Envoy (which uses the same platform as the Rainier) come into my shop. The owner had already replaced two shift solenoids based on a generic code reader, but the harsh 1-2 shift and intermittent ‘limp mode’ persisted. He was ready to give up and pay for a costly transmission rebuild. After a quick diagnostic, I suspected the TCM. The internal circuits can develop micro-fractures from heat cycles, causing intermittent signal loss that mimics solenoid failure. We installed a VIN-programmed T42 module, and the problem was solved instantly. It’s a classic example of how fixing the root cause with the right part, like this 2006-2007 Rainier TCM, saves hundreds, if not thousands, in unnecessary repairs.
Is Your Buick Showing These Telltale Signs?
A failing TCM doesn’t heal itself; the symptoms only get worse. If you’re noticing any of the following, it’s time for a replacement. Catching it early can prevent further damage to your transmission’s mechanical components.
- ✔ Abrupt, harsh, or delayed gear shifts.
- ✔ Transmission warning light or Check Engine Light is on.
- ✔ Diagnostic Trouble Codes (DTCs) stored, especially P0700, P0750, or other solenoid-related faults.
- ✔ Vehicle is stuck in a single gear (often called ‘limp mode’).
- ✔ Failure to upshift or downshift correctly.
- ✔ A noticeable drop in fuel efficiency.
- ✔ Complete loss of communication with the transmission.
A Straightforward Guide to Installation
Installing your new 2006-2007 Rainier TCM is a simple job that most DIYers can complete in their driveway in under 30 minutes. No specialized programming tools are needed.
- 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 Buick Rainier, the TCM is typically found in the engine compartment. Check common locations like the driver’s side (LH) of the engine bay.
- Disconnect and Remove: Carefully unplug the electrical connectors from the old TCM. Then, unbolt the module from its mounting bracket.
- Install the New Module: Bolt the new, pre-programmed TCM into place and securely reconnect the electrical connectors. Ensure they click into place.
- Final Steps: Reconnect the battery terminal. While the module is plug-and-play, it’s always best practice to use a standard OBD2 scan tool to clear any old fault codes from the vehicle’s memory. Start the vehicle and enjoy your smooth-shifting transmission!
Verified Vehicle Compatibility
This module is a direct-fit, VIN-programmed solution for your Buick, but its versatile T42 architecture was used across a wide range of GM vehicles. It is interchangeable with multiple part numbers, including 24252114, 24234503, and 24240400.
Guaranteed Fitment for:
- ✔ 2006-2007 Buick Rainier
This part is also confirmed to fit many other GM models from 2006-2014, such as the Chevrolet Silverado, Tahoe, Impala; GMC Sierra, Yukon; Cadillac DTS; Pontiac G6; and Hummer H3. Please verify your part number or contact us to ensure perfect fitment for your specific vehicle.
Do I need to have this TCM programmed by a dealer?
Do I need to have this TCM programmed by a dealer?
No. The main benefit of our service is that we program the module to your vehicle’s VIN before shipping. It arrives ready for immediate installation, saving you a trip to the dealership and additional programming fees.
Is this a difficult part to install myself?
Not at all. For most vehicles, including the 2006-2007 Rainier, this is a very straightforward job. It typically involves disconnecting the battery, unplugging a few connectors, and removing a few bolts. Most people with basic tools can do it in under 30 minutes.
What is the warranty on this part?
This transmission control module is backed by our comprehensive one-year warranty, giving you confidence and peace of mind in your repair.
Will this fix a P0700 trouble code?
A P0700 code is a general fault request from the TCM to the main engine computer (ECM) to turn on the check engine light. It indicates a problem exists within the transmission’s control system. If the underlying issue is a faulty TCM, then yes, replacing it with this module will resolve the cause and allow the code to be cleared.
Do I need to send my old part back?
No, there is no core charge or requirement to return your old module. You can keep it or dispose of it at your convenience.