Is Your Grand Prix Driving You Crazy with Shifting Problems?
If your 2006, 2007, or 2008 Pontiac Grand Prix is suffering from harsh shifting, getting stuck in gear, or throwing transmission-related check engine lights, you’re not alone. These are classic signs of a failing Transmission Control Module (TCM). As a technician with over two decades of experience, I’ve seen these T42 modules cause headaches for countless owners. The TCM is the brain of your automatic transmission, and when it fails, it can make your car feel unpredictable and unsafe. This isn’t just an annoyance; it’s a critical failure that impacts your car’s performance and fuel economy.
This is the definitive solution: a high-quality replacement T42 Transmission Control Module, part number 24234503. The best part? It arrives at your door fully programmed to your vehicle’s specific VIN. This means you can skip the expensive trip to the dealership for programming. It’s a direct-fit, plug-and-play repair that restores the crisp, smooth shifting you expect from your Grand Prix.
From the Diagnostic Bay
I remember a customer bringing in his ’07 Grand Prix GXP. The car was stuck in 3rd gear (limp mode), and another shop had quoted him over $2,000 for a transmission rebuild, blaming internal clutches. He was frustrated and ready to sell the car. I hooked up my scan tool and saw the tell-tale P0700 code, along with several solenoid circuit faults. Experience told me this wasn’t a mechanical failure; it was electrical. We swapped in a VIN-programmed TCM, cleared the codes, and took it for a test drive. The car shifted perfectly through all gears. We saved him thousands of dollars and a lot of heartache with a 30-minute fix. That’s the power of a correct diagnosis and the right part.
Common Signs of a Failing Grand Prix TCM
- ✔ Unpredictable, harsh, or delayed gear shifts.
- ✔ The vehicle is stuck in a single gear, often called “limp mode.”
- ✔ Check Engine Light or Transmission Warning Light is illuminated on the dash.
- ✔ Diagnostic Trouble Codes (DTCs) are present, such as P0700, P0750-P0758, or other solenoid-related faults.
- ✔ A noticeable drop in fuel efficiency.
- ✔ Complete loss of communication with the transmission module.
A Straightforward Guide to Installation
For the 2006-2008 Pontiac Grand Prix, this is a job most DIYers can handle in their own garage. The TCM is located under the lower air cleaner housing, making it accessible with basic hand tools.
- Safety First: Disconnect the negative terminal from your car’s battery to prevent any electrical shorts and to help reset the vehicle’s electronic systems.
- Access the Module: Remove the air cleaner box assembly to gain clear access to the TCM. It will have several large electrical connectors.
- Disconnect and Remove: Carefully unplug the wiring harnesses from the old TCM. Note their orientation. Then, unbolt the module from its mounting bracket.
- Install the New Module: Bolt the new, pre-programmed TCM into place. Securely reconnect the wiring harnesses, ensuring they click into place.
- Final Steps: Reinstall the air cleaner assembly and reconnect the battery terminal. Start the car and use a basic OBD2 scan tool to clear any stored fault codes. Take the vehicle for a test drive to confirm smooth operation.
Verified Vehicle Compatibility
This module is a direct replacement for part number 24234503 and other interchangeable numbers. While it is guaranteed to fit the specified vehicle, it is also compatible with a wide range of other GM models. Please verify your part number before ordering.
- Pontiac Grand Prix (2006-2008) – Located under the lower air cleaner housing.
- Pontiac G6 (2006-2010) – Located on the LH strut tower.
- Chevrolet Impala (2006-2011) – Located under the lower air cleaner housing.
- Chevrolet Monte Carlo (2006-2007) – Located under the lower air cleaner housing.
- Buick LaCrosse / Allure (2006-2009) – Located under the lower air cleaner housing.
- And many more GM vehicles. Refer to the full fitment list.
Frequently Asked Questions
Do I need to take this 2006-2008 Grand Prix TCM to a dealer for programming?
Do I need to take this 2006-2008 Grand Prix TCM to a dealer for programming?
No. This module comes pre-programmed to your car’s VIN. It’s a true plug-and-play solution that saves you the time, cost, and hassle of a dealership visit. Just provide your VIN during checkout.
Where is the TCM located on my Pontiac Grand Prix?
Do I need to take this 2006-2008 Grand Prix TCM to a dealer for programming?
No. This module comes pre-programmed to your car’s VIN. It’s a true plug-and-play solution that saves you the time, cost, and hassle of a dealership visit. Just provide your VIN during checkout.
Will this part fix a P0700 trouble code?
Do I need to take this 2006-2008 Grand Prix TCM to a dealer for programming?
No. This module comes pre-programmed to your car’s VIN. It’s a true plug-and-play solution that saves you the time, cost, and hassle of a dealership visit. Just provide your VIN during checkout.
What tools are required for this installation?
Do I need to take this 2006-2008 Grand Prix TCM to a dealer for programming?
No. This module comes pre-programmed to your car’s VIN. It’s a true plug-and-play solution that saves you the time, cost, and hassle of a dealership visit. Just provide your VIN during checkout.
Is there a core charge for my old part?
Do I need to take this 2006-2008 Grand Prix TCM to a dealer for programming?
No. This module comes pre-programmed to your car’s VIN. It’s a true plug-and-play solution that saves you the time, cost, and hassle of a dealership visit. Just provide your VIN during checkout.