Restore Your Minivan’s Drivability and Peace of Mind
If your 2006-2007 Buick Terraza is suffering from jarring shifts, getting stuck in gear, or has thrown a transmission-related check engine light, you’re not just dealing with an annoyance—you’re facing a potential reliability issue. As a technician with over two decades of experience, I’ve seen firsthand how a failing Transmission Control Module (TCM) can turn a dependable family vehicle into a source of constant stress. This T42 TCM, part number 24239926, is the definitive solution to restore the smooth, predictable performance your Terraza was built for.
The TCM is the brain of your automatic transmission. It processes data from various sensors to control shift solenoids, manage torque converter clutch lockup, and regulate line pressure. When it fails, communication breaks down, leading to the frustrating and sometimes dangerous symptoms you’re experiencing. This module is pre-programmed to your vehicle’s specific VIN, ensuring it works perfectly out of the box without a costly trip to the dealership for programming.
A Technician’s Notebook: The Intermittent Shifting Mystery
I remember a 2007 Terraza that came into the shop with a complaint that stumped the owner. The van would shift perfectly for days, then suddenly start slamming into gear or refuse to shift out of 2nd. There were no consistent codes, just a generic P0700 (Transmission Control System Malfunction) that would pop up and disappear. After checking the wiring and fluid, I suspected the TCM. On these GM T42 modules, internal circuit board connections can weaken over time. When the module heats up during a long drive, the connection fails, causing the erratic behavior. Once it cools, it works again. We installed a VIN-programmed TCM, and the problem never returned. This isn’t just a part replacement; it’s a permanent fix for a common, tricky diagnostic issue.
Is Your Terraza Exhibiting These Transmission Problems?
A faulty TCM can manifest in several ways. If you’re noticing any of the following, it’s a strong indicator that your module needs replacement. Addressing it now can prevent further damage to your transmission’s mechanical components.
- ✔ Harsh, erratic, or delayed gear shifts.
- ✔ Vehicle is stuck in “limp mode” (usually 2nd or 3rd gear).
- ✔ Check Engine Light or Transmission Warning Light is on.
- ✔ Diagnostic Trouble Codes (DTCs) are present, such as P0700, P0750-P0758 (solenoid codes), or U-series communication codes.
- ✔ Sudden loss of power or poor acceleration.
- ✔ Decreased fuel economy due to inefficient shifting.
- ✔ The transmission seems to slip between gears.
A Straightforward Guide to Installation
One of the best features of this module is its accessibility for the DIY mechanic. For the 2006-2007 Buick Terraza, the TCM is located in a very accessible spot, making for a quick swap. You can have your van back on the road in under 30 minutes.
- Safety First: Disconnect the negative terminal from your vehicle’s battery to prevent electrical shorts and reset the system.
- Locate the TCM: On your Terraza, the TCM is mounted on the driver’s side strut tower in the engine compartment. It’s a silver box with electrical connectors.
- Disconnect the Wiring: Carefully release the locking tabs on the electrical harness connectors and pull them straight off the module. Avoid pulling on the wires themselves.
- Remove the Old Module: Unbolt the mounting hardware holding the old TCM to the strut tower and remove it from the vehicle.
- Install the New Module: Mount your new, VIN-programmed TCM in the same location, securing it with the original hardware.
- Reconnect Everything: Plug the wiring harnesses back into the new module until they click securely in place. Reconnect the negative battery terminal.
- Final Steps: Start the vehicle. While the module is plug-and-play, it’s good practice to use a basic OBD2 scan tool to confirm no old fault codes are stored in other systems.
Verified Vehicle Compatibility
This T42 Transmission Control Module is a direct-fit replacement for the following vehicle, ensuring OEM-level function and reliability. We use your VIN to load the exact software your vehicle requires.
- ✔ Buick Terraza: 2006-2007 (Transmission control, located on LH strut tower)
- ✔ Also fits other compatible GM models including the Uplander, Montana, and Rendezvous. This module is interchangeable with part numbers 24239926, 24252114, 24234503, and more.
Do I need to take my van to the dealer after installation?
Do I need to take my van to the dealer after installation?
No. This Transmission Control Module comes fully programmed to your vehicle’s VIN. It is a true plug-and-play solution, saving you the time and expense of a dealership visit for programming.
What if I install this and still have issues?
While this TCM resolves the most common transmission electronic faults, shifting problems can also stem from mechanical issues (like bad solenoids or worn clutches) or wiring problems. Our expert support team is here to help you diagnose the issue further if needed.
Is there a core charge for my old part?
No, there is no core charge. You can keep or recycle your old part without the hassle of shipping it back, making the repair process simpler and more convenient for you.
Will this fix a P0700 trouble code?
A P0700 code is a general fault code indicating the TCM has detected a problem. In many cases, a failing TCM is the root cause. Replacing it often clears the P0700 and any related specific codes (like for solenoids). However, you should always diagnose any other specific codes that accompany the P0700.