Restore Smooth Shifting to Your Buick Terraza
If your 2006-2007 Buick Terraza is suffering from harsh shifting, getting stuck in gear, or throwing transmission codes, you’re not just dealing with an annoyance—you’re facing a potential breakdown. As a technician with over two decades of experience, I’ve seen countless GM vehicles sidelined by a faulty Transmission Control Module (TCM). The T42 module, specifically part number 24240400, is the electronic brain of your automatic transmission, and when it fails, the symptoms can be dramatic and frustrating. This replacement TCM is the reliable, direct-fit solution to get your family’s minivan back on the road with confidence.
We take the guesswork and dealership hassle out of the repair. Each module is expertly programmed to your vehicle’s specific VIN before it ships. This means no expensive trips to the dealer for programming—it arrives ready for a true plug-and-play installation. This isn’t just a replacement part; it’s a permanent fix designed to restore the precise, smooth performance you expect from your vehicle’s 4-speed automatic transmission.
Case Study: A Tricky Diagnosis
A customer brought in their 2007 Terraza with a complaint of intermittent, bone-jarring shifts from 1st to 2nd gear, but only after it was fully warmed up. They had already replaced a shift solenoid with no luck. The scan tool showed a generic P0700 code, but nothing specific. In these cases, heat-soak failure of the TCM is a common culprit. The tiny processors and solder joints inside the module expand and contract, causing intermittent connection loss. We swapped in a VIN-programmed T42 module, and the problem vanished instantly. This highlights why replacing a failing 2006-2007 Terraza TCM is often the correct fix when symptoms are inconsistent.
Is Your Terraza Exhibiting These Telltale Signs?
A failing TCM will give you clear warnings. If you’re experiencing any of the following, it’s a strong indicator that your module needs replacement:
- ✔ Harsh, jerky, or delayed gear shifts.
- ✔ The vehicle is stuck in “limp mode” (usually 2nd or 3rd gear).
- ✔ Check Engine Light or Transmission Warning Light is on.
- ✔ Diagnostic Trouble Codes (DTCs) such as P0700, P0750, P0753, or other solenoid-related faults are present.
- ✔ Complete failure to shift up or down.
- ✔ A noticeable drop in fuel economy.
Your Straightforward TCM Installation Guide
Installing your new 2006-2007 Terraza TCM is a job most DIYers can handle in under 30 minutes with basic tools. On the Terraza, this module is typically located on the driver’s side of the engine bay, mounted to the strut tower.
- Safety First: Always disconnect the negative terminal from your vehicle’s battery before starting any electrical work.
- Locate the Module: Find the TCM on the driver’s side strut tower. It’s a silver box with electrical connectors.
- Disconnect and Remove: Carefully unclip the wiring harnesses. Then, unbolt the module from its mounting bracket.
- Install the New Module: Bolt the new, pre-programmed TCM into place and securely reconnect the wiring harnesses. Ensure they click into place.
- Reconnect and Verify: Reconnect the battery terminal. Start the vehicle and check for any warning lights. While not always necessary, using a scan tool to clear any stored historical codes is good practice.
Verified Vehicle Compatibility List
This T42 TCM is a direct replacement for part number 24240400 and is interchangeable with a wide range of other GM service numbers. While this page focuses on the 2006-2007 Terraza TCM, this part also fits the following vehicles. Please verify your model and options below.
- Buick: Allure (06-09), LaCrosse (06-09), Lucerne (06-11), Rainier (06-07), Rendezvous (06-07)
- Cadillac: DTS (06-11)
- Chevrolet: Avalanche 1500 (07-08), Cobalt (06-10), Colorado (08-12), Express Vans (06-14), HHR (06-11), Impala (06-11), Malibu (06-10), Monte Carlo (06-07), Silverado Pickups (07-13), SSR (05-06), Suburban 1500 (07-08), Tahoe (07-09)
- GMC: Canyon (08-12), Envoy / Envoy XL (06-09), Savana Vans (06-14), Sierra Pickups (07-13), Yukon / Yukon XL 1500 (07-09)
- Hummer: H3 (08-10)
- Pontiac: G5 (07-10), G6 (06-10), Grand Prix (06-08), Pursuit (06)
- Saab: 9-7X (06-09)
- Saturn: Aura (07-09), Ion (06-07), Vue (07-10)
- Uplander / Montana / Terraza / Relay Minivans: (06-09)
What does ‘VIN Programmed’ actually mean?
What does ‘VIN Programmed’ actually mean?
It means we load your vehicle’s unique Vehicle Identification Number (VIN) and the latest GM software onto the module before shipping. This ensures it communicates perfectly with your vehicle’s engine computer and other systems right out of the box, eliminating the need for expensive dealership programming.
Do I need to return my old TCM?
No, there is no core charge or need to return your old part. You can dispose of it or keep it, making the process faster and more convenient for you.
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. While a faulty TCM is a very common cause, this code can also be triggered by internal transmission issues. However, if P0700 is accompanied by shifting problems or other specific TCM codes, replacing the module is very likely the correct repair.
Is any special relearn procedure required after installation?
No special relearn procedure is needed. Because the module is pre-programmed to your VIN, your vehicle will recognize it upon startup. The transmission will adapt its shift points naturally over the first few drive cycles.