Restore Your Grand Prix’s Smooth Shifting Performance
If your 2006-2008 Pontiac Grand Prix is suffering from harsh shifts, getting stuck in gear, or throwing transmission codes, the culprit is often a failing Transmission Control Module (TCM). As an automotive diagnostician with over two decades of experience, I’ve seen countless drivers worry they need a costly transmission rebuild when the real issue is this electronic module. This T42 TCM, part number 24239224, is the definitive solution. It arrives at your door pre-programmed to your vehicle’s specific VIN, eliminating the need for expensive dealership flashing. It’s a direct-fit, plug-and-play repair that restores the precise, reliable shifting you expect from your vehicle.
A Technician’s Notebook
I remember a 2007 Grand Prix that came into the shop stuck in 3rd gear (limp mode) with a P0700 code on the scanner. The owner was convinced his 4L60E transmission was shot. After a quick check of the basics, I suspected the TCM. These T42 modules, especially on vehicles of this era, are prone to internal circuit failure from heat and vibration. We swapped in a VIN-programmed module just like this one, cleared the codes, and the car was shifting perfectly within 30 minutes. It’s a textbook repair that saves customers hundreds, if not thousands, of dollars over a misdiagnosed transmission replacement.
Is Your Grand Prix Showing These Red Flags?
A failing TCM doesn’t always mean total transmission failure. Often, it presents as a series of frustrating and intermittent electrical issues. If you’re experiencing any of the following, it’s a strong indicator that your 2006-2008 Grand Prix TCM needs replacement:
- ✔ Harsh, slamming, or erratic gear changes.
- ✔ The vehicle is stuck in a single gear (limp mode) and won’t shift up or down.
- ✔ Check Engine Light or Transmission Warning Light is illuminated.
- ✔ Diagnostic Trouble Codes (DTCs) are present, such as P0700 (Transmission Control System Malfunction), P0750-P0758 (Shift Solenoid Errors), or other transmission-related faults.
- ✔ Delayed engagement when shifting from Park to Drive or Reverse.
- ✔ A noticeable drop in fuel economy due to inefficient shifting.
A Straightforward Guide to Installation
For the Pontiac Grand Prix, this is a repair that a confident DIYer can handle with basic tools. The module is typically located under the lower air cleaner housing, making it accessible from the top of the engine bay. The entire process should take less than an hour.
- Safety First: Disconnect the negative terminal from your vehicle’s battery to prevent any electrical shorts and to help reset the system.
- Locate the Module: Remove the air cleaner box assembly to gain access to the old TCM. It will have several large electrical connectors attached.
- Swap the Part: Carefully unplug the wiring harnesses from the old module. Unbolt it from its mounting bracket and set it aside. Bolt the new module in its place.
- Reconnect and Finalize: Securely plug the wiring harnesses into your new TCM. You should hear a ‘click’ as they lock into place. Reinstall the air cleaner assembly.
- Power Up: Reconnect the battery terminal. Start the vehicle and allow it to idle for a few minutes. Use a basic OBD2 scan tool to clear any stored transmission codes before your test drive.
Verified Vehicle Fitment
While this listing is tailored for the 2006-2008 Grand Prix TCM, this versatile T42 module is compatible with a wide range of General Motors vehicles. It is a direct replacement for multiple part numbers, including 24252114, 24234503, 24239224, and more. Please verify your part number or use our vehicle selector to ensure a perfect match.
This part fits the 2006-2008 Pontiac Grand Prix (located under the lower air cleaner housing) and other GM models such as:
- Chevrolet Impala, Monte Carlo, Cobalt, HHR, Silverado, Tahoe
- GMC Sierra, Yukon, Savana
- Buick LaCrosse, Lucerne
- Pontiac G6, G5
- And many more from 2006-2014.
Frequently Asked Questions
What exactly is VIN programming and why do I need it?
VIN programming loads your vehicle’s unique identification number and specific software parameters onto the module. This ensures the TCM communicates perfectly with your engine computer and transmission for optimal shift points, torque converter lockup, and fuel efficiency. Without it, the part simply will not work correctly. Our service saves you a mandatory trip to the dealership.
Is this a new or used part?
This is a high-quality, OEM-standard replacement part, not a used component from a junkyard. It is inspected and programmed to meet or exceed original factory specifications and is backed by our one-year warranty for your peace of mind.
Will I have to send my old part back (core charge)?
No, there is no core charge on this item. You can keep your old part, making the replacement process faster and more convenient for you.
Can I install this myself if I have basic mechanical skills?
Absolutely. For the Grand Prix, the location under the air cleaner housing is accessible. With basic hand tools and our guide, most DIY enthusiasts can complete the installation in under an hour. The key is that our pre-programming removes the most difficult step—the computer work.
What if I still have a Check Engine Light after installation?
After installing the new TCM, it’s crucial to use an OBD2 scan tool to clear any pre-existing trouble codes from the vehicle’s memory. The old codes will not clear themselves automatically. If a light returns after clearing, it may indicate a separate issue that needs diagnosis.