Restore Your Pontiac’s Shifting Performance
If your 2006-2008 Pontiac Grand Prix is suffering from harsh shifts, delayed gear engagement, or is stuck in limp mode, a failing Transmission Control Module (TCM) is the most likely culprit. As a seasoned technician, I’ve seen these T42 modules cause countless headaches for drivers. This replacement TCM, part number 24243921, is the definitive solution to get your vehicle driving smoothly again. It’s the electronic brain of your automatic transmission, precisely managing shift solenoids, line pressure, and torque converter lockup. Don’t let a faulty module sideline your car—this is the reliable fix you need.
From the Diagnostic Bay: The Grand Prix That Wouldn’t Shift
A customer brought in their ’07 Grand Prix with the classic symptoms: the transmission was banging into gear, and the check engine light was on. A quick scan showed a P0700 (Transmission Control System Malfunction) code. Instead of jumping to a costly transmission rebuild, we checked the TCM. After confirming the module was faulty, we installed one of these VIN-programmed units. The entire job took less than an hour in the bay. The customer drove away with a car that shifted like new, saving hundreds compared to a dealership visit for programming alone. This is a perfect example of how the right part makes for an easy, effective repair.
Is Your Grand Prix Showing These Signs of TCM Failure?
A failing TCM will give you clear warning signs. Ignoring them can lead to more significant transmission damage. If you’re experiencing any of the following, it’s time to consider a replacement 2006-2008 Grand Prix TCM.
- ✔ Harsh, erratic, or delayed gear shifting.
- ✔ Vehicle is stuck in a single gear (limp mode).
- ✔ Check Engine Light or Transmission Warning Light is illuminated.
- ✔ Diagnostic Trouble Codes (DTCs) like P0700, P0750, or other solenoid-related codes are present.
- ✔ Poor acceleration and decreased fuel efficiency.
- ✔ Complete loss of communication with the transmission module.
A Straightforward Guide to Installation
One of the best features of this module is its simple, DIY-friendly installation. Because it comes pre-programmed to your VIN, you can skip the expensive trip to the dealership. For the Pontiac Grand Prix, the process is very accessible.
- Safety First: Disconnect the negative terminal from your vehicle’s battery to prevent any electrical shorts.
- Locate the TCM: On your 2006-2008 Grand Prix, the TCM is typically found underneath the air cleaner housing. You will need to remove the airbox to access it.
- Disconnect and Remove: Carefully unplug the electrical connectors from the old module. Then, unbolt the module from its mounting bracket.
- Install the New Module: Bolt the new TCM into place and securely plug in the electrical connectors. Reinstall the air cleaner housing.
- Final Steps: Reconnect the battery terminal. While the module is plug-and-play, it’s good practice to use a basic OBD2 scanner to clear any stored fault codes from the vehicle’s memory.
Verified Vehicle Compatibility
This T42 Transmission Control Module is a direct replacement for part number 24243921 and other interchangeable numbers. It is guaranteed to fit the following vehicles, including the 2006-2008 Grand Prix TCM application:
- Pontiac Grand Prix (2006-2008) – Transmission; (lower air cleaner housing)
- Buick Allure (2006-2009) – Transmission; (lower air cleaner housing)
- Buick LaCrosse (2006-2009) – Transmission; (lower air cleaner housing)
- Buick Lucerne (2006-2011) – Transmission; (LH engine compartment)
- Chevrolet Impala (2006-2011) – Transmission; (lower air cleaner housing)
- Chevrolet Monte Carlo (2006-2007) – Transmission; (lower air cleaner housing)
- And many other GM models from 2006-2014. Please verify your part number for a perfect match.
Frequently Asked Questions
What does “VIN Programmed” mean for me?
It means the module arrives at your door ready for installation. We flash it with your vehicle’s specific Vehicle Identification Number (VIN) and the latest GM software. This ensures it communicates perfectly with your car’s other computers, eliminating the need for a dealership visit and extra programming fees.
Is this part difficult to install on my Grand Prix?
Not at all. For a DIY enthusiast with basic hand tools, this is a very straightforward job. The module is located under the air cleaner housing, making it accessible in your own garage. The entire process typically takes under an hour.
Will this fix my transmission shifting problems?
If your vehicle’s symptoms match those of a failing TCM (like harsh shifting, limp mode, or specific DTCs), this module is the correct and reliable solution. It directly resolves the electronic faults that cause these common transmission issues.
Do I need to send my old part back?
No, there is no core charge for this part. You can keep your old module or dispose of it responsibly without any hassle.
What kind of warranty comes with this 2006-2008 Grand Prix TCM?
This module is backed by our one-year warranty, giving you peace of mind and confidence in your repair. We stand by the quality and reliability of our electronic components.