Restore Flawless Shifting to Your Pontiac Grand Prix
If you’re dealing with the headaches of a faulty transmission—erratic shifting, getting stuck in gear, or a persistent check engine light—you’re not alone. As a technician with over two decades of experience, I’ve seen countless GM vehicles, especially the 2006-2008 Pontiac Grand Prix, come into the shop with these exact issues. The culprit is often a failing Transmission Control Module (TCM), the electronic brain that orchestrates every shift. This replacement T42 TCM, part number 24235340, is the definitive, long-term solution to get your car driving like new again.
We take the guesswork and high dealership costs out of the equation. Each module is expertly programmed to your vehicle’s specific VIN before it ships, ensuring it works perfectly right out of the box. This isn’t just a part; it’s a complete fix that restores communication between your engine and transmission, solving common diagnostic trouble codes (DTCs) and drivability problems without needing a trip to the dealer for expensive programming. This is the most reliable way to fix your 2006-2008 Grand Prix TCM and regain confidence on the road.
Case Study: The Grand Prix Stuck in Limp Mode
A customer brought in his ’07 Grand Prix, frustrated because it was stuck in 3rd gear (limp mode) and had a P0700 code. He’d already replaced two shift solenoids based on a generic code reader’s suggestion, but the problem persisted. After a quick diagnostic, I suspected the TCM. The module’s internal circuits that control those solenoids had failed, not the solenoids themselves. We installed one of our VIN-programmed T42 modules, cleared the codes, and the car shifted perfectly on the test drive. He could have saved hundreds of dollars and a lot of frustration by addressing the root cause first—a faulty 2006-2008 Grand Prix TCM.
Is Your Grand Prix Showing These Telltale Signs?
A failing TCM can manifest in several ways. If you’re experiencing any of the following, it’s a strong indicator that your module needs replacement:
- ✔ Harsh, slamming shifts or delayed gear engagement.
- ✔ Vehicle is stuck in one gear (often called “limp mode”).
- ✔ Check Engine Light or Transmission Warning Light is on.
- ✔ Diagnostic codes like P0700 (Transmission Control System Malfunction), P0750-P0758 (Shift Solenoid Faults), or other transmission-related codes are present.
- ✔ Failure to upshift or downshift properly.
- ✔ A noticeable decrease in fuel economy.
- ✔ The transmission feels like it’s slipping between gears.
A Straightforward Guide to Replacing Your Grand Prix TCM
For the 2006-2008 Pontiac Grand Prix, this is a job most DIYers can handle in under 30 minutes with basic tools. The module is conveniently located under the air cleaner housing.
- Safety First: Disconnect the negative terminal from your car’s battery to prevent any electrical shorts and to help reset the system.
- Access the Module: Remove the engine air cleaner box assembly. This will expose the TCM mounted below it.
- 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 your new, pre-programmed TCM into place. Reconnect the electrical connectors, ensuring they click securely into place.
- Reassemble and Finalize: Reinstall the air cleaner housing. Reconnect the battery terminal. While our programming resolves most issues, it’s best practice to use a basic OBD2 scan tool to clear any stored fault codes from the vehicle’s memory.
Verified Vehicle Compatibility
This T42 TCM is a direct replacement for a wide range of General Motors vehicles. While this page focuses on the 2006-2008 Grand Prix TCM, it is also compatible with the following models. Always verify your part number (24235340 or an interchange) for a perfect match.
- Pontiac: Grand Prix (2006-2008), G6, G5, Pursuit, Montana
- Chevrolet: Impala, Monte Carlo, Silverado, Tahoe, Suburban, Avalanche, Express, Cobalt, HHR, Colorado
- GMC: Sierra, Yukon, Savana, Envoy, Canyon
- Buick: LaCrosse, Allure, Lucerne, Rainier, Rendezvous
- Cadillac: DTS
- Saturn: Aura, Ion, Vue
- Hummer: H3
- Saab: 9-7X
Do I need to get this TCM programmed by a dealer?
Do I need to get this TCM programmed by a dealer?
No. The main benefit of our service is that we program the module to your car’s VIN before shipping. This makes it a true plug-and-play solution, saving you the time and expense of a dealership visit.
Is this part number 24235340 the same as other service numbers?
Yes, part number 24235340 is interchangeable with many other GM service numbers, including 24242391, 24234503, 24252114, and others. This module is the correct replacement for any of those part numbers.
What tools do I need for installation on my Grand Prix?
You’ll only need basic hand tools: a socket set to remove the air cleaner housing and the bolts holding the TCM bracket, and a wrench to disconnect the battery terminal. No specialized equipment is required.
What if my problem isn’t fixed after installing this part?
While this TCM is the most common cause of these symptoms, transmission issues can sometimes be mechanical. We offer a one-year warranty on the module and have expert support available to help you troubleshoot. We recommend ensuring the transmission fluid level and condition are good and that there are no major mechanical failures.