Fix Your Terraza’s Shifting Problems for Good
Is your 2006-2007 Buick Terraza suffering from harsh, erratic shifting, or getting stuck in gear? A failing Transmission Control Module (TCM) is one of the most common culprits. As a technician with over two decades of experience, I’ve seen countless GM vehicles, including the Terraza, sidelined by these exact issues. This T42 TCM, service part number 24239926, is the definitive solution, arriving at your door pre-programmed to your vehicle’s specific VIN. This means no expensive dealership visits for programming—it’s a true plug-and-play fix that restores the smooth, reliable performance your family depends on.
From the Service Bay: The Case of the Hesitant Minivan
From the Service Bay: The Case of the Hesitant Minivan
A customer brought in their family’s 2007 Terraza, complaining of unnerving transmission behavior. It would hesitate when accelerating from a stop and sometimes slam into the next gear, making for a jerky ride. The check engine light was on, and my scan tool pulled a P0700 (Transmission Control System Malfunction) and a P0752 (Shift Solenoid ‘A’ Stuck On). While the solenoid code pointed to a potential internal issue, my experience with these T42 modules suggested otherwise. Heat and vibration, especially where this module is located on the Terraza, can cause internal circuit failures that mimic solenoid problems. We installed one of our VIN-programmed TCMs, and the problem vanished instantly. The van shifted like new, proving that a reliable electronic fix can save you from a costly and unnecessary transmission teardown.
Is Your Terraza Exhibiting These Transmission Faults?
A bad TCM can manifest in several ways. If you’re experiencing any of the following, this module is your likely solution. Catching it early can prevent further damage to your transmission.
- ✔ Harsh, banging shifts or delayed gear engagement.
- ✔ The vehicle is stuck in “limp mode” (usually 2nd or 3rd gear) and won’t shift.
- ✔ Check Engine Light or Transmission Warning Light is illuminated with codes like P0700, P0750, P0751, P0752, or other solenoid-related DTCs.
- ✔ Complete loss of upshifting or downshifting capabilities.
- ✔ Poor acceleration and a noticeable drop in fuel economy.
- ✔ Intermittent communication loss with the transmission module.
A Straightforward Guide to Installation
Replacing the 2006-2007 Terraza TCM is a job most DIYers can handle in under 30 minutes with basic tools. This module is conveniently located to make the swap simple.
- Safety First: Always disconnect the negative terminal from your vehicle’s battery before starting any electronic repair.
- Locate the Module: On your Buick Terraza, the TCM is mounted on the driver’s side, near the top of the strut tower in the engine bay.
- Disconnect and Remove: Carefully unplug the electrical connectors. Press the release tabs firmly to avoid damaging them. 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 harnesses. You should hear a click as they lock in.
- Final Steps: Reconnect the battery terminal. Start the vehicle and allow it to idle for a few minutes. While the module is pre-programmed, it’s good practice to use a basic scan tool to clear any stored fault codes from the ECU.
Verified Vehicle Compatibility
This T42 Transmission Control Module is a guaranteed fit for the following vehicles:
- 2006-2007 Buick Terraza (Located at LH strut tower)
It also serves as a direct replacement for a wide range of other GM vehicles from 2006-2014, including the Chevrolet Uplander, Pontiac Montana, Saturn Relay, and many more that use the T42 platform. It is interchangeable with part numbers 24234503, 24252114, 24239224, and others listed in the full compatibility chart.
Frequently Asked Questions
From the Service Bay: The Case of the Hesitant Minivan
A customer brought in their family’s 2007 Terraza, complaining of unnerving transmission behavior. It would hesitate when accelerating from a stop and sometimes slam into the next gear, making for a jerky ride. The check engine light was on, and my scan tool pulled a P0700 (Transmission Control System Malfunction) and a P0752 (Shift Solenoid ‘A’ Stuck On). While the solenoid code pointed to a potential internal issue, my experience with these T42 modules suggested otherwise. Heat and vibration, especially where this module is located on the Terraza, can cause internal circuit failures that mimic solenoid problems. We installed one of our VIN-programmed TCMs, and the problem vanished instantly. The van shifted like new, proving that a reliable electronic fix can save you from a costly and unnecessary transmission teardown.