If your 2006-2008 Pontiac Grand Prix is suffering from harsh shifting, getting stuck in gear, or throwing transmission codes, you’ve come to the right place. As a technician with over two decades of experience, I’ve seen countless GM vehicles sidelined by a faulty Transmission Control Module (TCM). This isn’t just an annoyance; it’s a critical failure that can affect your car’s performance and safety. This T42 TCM, part number 24240449, is the definitive, reliable solution to get your Grand Prix driving smoothly again.
The TCM is the brain of your automatic transmission, responsible for managing every gear change, controlling the torque converter, and monitoring system health. When it fails, the symptoms are unmistakable and frustrating. This replacement module is meticulously prepared to OEM specifications and, most importantly, comes pre-programmed to your vehicle’s specific VIN. This means you can skip the expensive trip to the dealership for programming—it’s a true plug-and-play fix that you or your mechanic can install with basic tools.
Case Study: A Tricky Diagnosis
I remember a customer bringing in a 2007 Grand Prix GXP. The car would intermittently refuse to shift out of 2nd gear and had a generic P0700 (Transmission Control System Malfunction) code. They had already replaced two shift solenoids with no luck. After connecting my scan tool, I noticed erratic voltage readings from the TCM itself. Heat soak was causing internal circuit failure—a classic T42 issue. We installed one of our VIN-programmed modules, and the car was shifting perfectly within the hour. This isn’t just selling a part; it’s providing a proven solution to a common and often misdiagnosed problem.
Common Signs of a Failing TCM
A failing 2006-2008 Grand Prix TCM can manifest in several ways. If you’re experiencing any of the following, a faulty module is the likely culprit:
- ✔ Harsh, banging shifts or delayed gear engagement.
- ✔ The vehicle is stuck in “limp mode” (usually second or third gear).
- ✔ Check Engine Light or Transmission Warning Light is illuminated.
- ✔ Diagnostic Trouble Codes (DTCs) like P0700, P0750, or other solenoid-specific codes are present.
- ✔ Complete loss of shifting capability or intermittent communication failure.
- ✔ Poor fuel economy and a feeling of sluggish performance.
A Straightforward Guide to Installation
One of the best parts about this solution is its simplicity. For the Pontiac Grand Prix, the TCM is typically located under the air cleaner housing, making it accessible. The entire process should take less than 30 minutes.
- Safety First: Always disconnect the negative terminal on your vehicle’s battery before starting any electronic work.
- Locate the Module: On your Grand Prix, remove the air cleaner box assembly to access the TCM mounted below it.
- Disconnect and Remove: Carefully unplug the electrical connectors from the old module. Then, unbolt the module from its mounting bracket.
- Install the New TCM: Mount the new module securely onto the bracket and reconnect the electrical harnesses. Ensure they click into place.
- Final Steps: Reinstall the air cleaner assembly and reconnect the battery. While the module is plug-and-play, it’s good practice to use a scan tool to clear any stored fault codes.
Verified Vehicle Compatibility
While this is the correct part for your 2006-2008 Grand Prix TCM replacement, this versatile T42 module also fits a wide array of other General Motors vehicles. Please verify your specific model and part number. This module is a direct replacement for service numbers such as 24252114, 24234503, 24240449, and others.
- ✔ Pontiac: Grand Prix (06-08), G6 (06-10), G5 (07-10), Pursuit (06), Montana (06-09)
- ✔ Chevrolet: Impala (06-11), Monte Carlo (06-07), Cobalt (06-10), HHR (06-11), Malibu (06-10), Silverado, Tahoe, Express Van
- ✔ Buick: LaCrosse (06-09), Allure (06-09), Lucerne (06-11), Rainier (06-07), Rendezvous (06-07)
- ✔ GMC: Sierra, Yukon, Savana Van, Envoy (06-09), Canyon (08-12)
- ✔ Saturn: Aura (07-09), Ion (06-07), Vue (07-10)
- ✔ And many more GM models.
Frequently Asked Questions
Frequently Asked Questions
Do I need to take my car to the dealer after installing this?
No. This module comes fully programmed to your vehicle’s VIN. It is a direct, plug-and-play replacement that requires no additional programming or dealership visits.
What information do you need to program the module?
We require your vehicle’s 17-digit Vehicle Identification Number (VIN) at checkout to ensure the module is programmed with the correct software for your specific car.
Is this part difficult to install for a DIYer?
Not at all. For the Grand Prix, it’s located under the air filter box. With basic hand tools and our guide, most DIY enthusiasts can complete the job in under 30 minutes.
What is the warranty on this TCM?
This part is backed by our comprehensive one-year warranty, giving you peace of mind and confidence in your repair.
Will this fix a P0700 code?
A P0700 code is a general transmission fault code, indicating the TCM has detected a problem. In many cases, a failing TCM is the root cause. Replacing it with our programmed unit often resolves the P0700 and any related specific codes.
Does this part require a core charge?
No, there is no core charge. You are not required to send your old, faulty part back to us, saving you time and hassle.