Restore Crisp, Reliable Shifting to Your Pontiac Grand Prix
If your 2006-2008 Pontiac Grand Prix is suffering from harsh shifts, getting stuck in gear, or throwing transmission codes, you’ve likely pinpointed the culprit: a failing Transmission Control Module (TCM). As a technician with over two decades of experience, I’ve seen countless GM vehicles, including the Grand Prix, sidelined by this exact issue. The TCM is the brain of your automatic transmission, and when it fails, it can cause unpredictable behavior that’s not only frustrating but can also lead to more severe transmission damage if ignored. This isn’t just a part; it’s the solution to get your car driving smoothly and dependably again.
This OEM-quality T42 TCM, part number 24239926, is the definitive fix. We take the guesswork and extra cost out of the repair by programming the module to your vehicle’s specific VIN before it ships. This means no expensive trips to the dealership for programming. It arrives at your door ready for a direct, plug-and-play installation, pre-loaded with the latest GM software updates to ensure optimal performance and communication with your vehicle’s other systems. For anyone tackling this job, from a seasoned mechanic to a weekend DIYer, our 2006-2008 Grand Prix TCM makes the repair process straightforward and effective.
From the Diagnostic Bay: A Grand Prix Saved from Limp Mode
A customer brought in their ’07 Grand Prix, complaining it was stuck in 3rd gear (limp mode) and the check engine light was on. The shifts leading up to this were jarring and unpredictable. A quick scan pulled a P0700 (Transmission Control System Malfunction) and a P0752 (Shift Solenoid ‘A’ Stuck On). While the solenoid code pointed to a specific component, my experience with these platforms suggested the TCM was the more likely root cause. The internal drivers that control the solenoids often fail. Instead of a complex internal transmission repair, we started with the brain. After installing one of our VIN-programmed T42 modules—a 20-minute job—we cleared the codes and took it for a test drive. The shifts were immediately smooth and precise. The problem was solved without ever opening the transmission pan, saving the customer hundreds in labor and diagnostic time.
Is Your Grand Prix Showing These Red Flags?
A failing TCM doesn’t always mean a complete transmission failure. Catching these early signs can save you from a much costlier repair down the road. Look out for:
- âś” Harsh, banging, or delayed gear shifts.
- âś” The vehicle feels stuck in one gear (often called “limp mode”).
- âś” An illuminated Check Engine Light or Transmission Warning Light.
- âś” Diagnostic Trouble Codes (DTCs) such as P0700, P0750-P0758, or other solenoid-related faults.
- âś” Failure to upshift or downshift properly.
- âś” A noticeable decrease in fuel economy.
- âś” Intermittent loss of communication with the scan tool.
Simple Installation for Your Grand Prix
Getting your car back to normal is easier than you think. For the 2006-2008 Pontiac Grand Prix, the TCM is located under the lower air cleaner housing, making it accessible for a straightforward replacement. No special lifts or tools are required.
- Safety First: Disconnect the negative terminal from your vehicle’s battery to prevent any electrical shorts and help reset the system.
- Access the Module: Locate and remove the air cleaner assembly to gain clear access to the TCM.
- Disconnect and Remove: Carefully unplug the electrical connectors from the old TCM. Then, unbolt the module from its mounting bracket.
- Install the New TCM: Mount your new, pre-programmed module in place, ensuring it is secure. Reconnect the electrical connectors firmly until they click.
- Reassemble and Finalize: Reinstall the air cleaner assembly. Reconnect the battery terminal. Start the vehicle and allow it to idle for a few minutes. While not always necessary, using a basic scan tool to clear any stored codes is a good final step.
Verified Vehicle Compatibility
This T42 TCM is a direct replacement for a wide range of General Motors vehicles. While this listing is focused on the 2006-2008 Grand Prix TCM, it is also compatible with the following models. Please verify your part number (24239926 or an interchange) for a guaranteed fit.
- Pontiac: Grand Prix (06-08), G6 (06-10), G5 (07-10), Montana (06-09), Pursuit (06), Torrent
- Chevrolet: Silverado, Tahoe, Suburban, Impala (06-11), Monte Carlo (06-07), Cobalt (06-10), HHR (06-11), Express Van, Colorado
- GMC: Sierra, Yukon, Savana Van, Canyon, Envoy
- Buick: LaCrosse (06-09), Lucerne (06-11), Allure (06-09), Rainier (06-07)
- Saturn: Aura (07-09), Vue (07-10), Ion (06-07)
- Cadillac: DTS (06-11)
- Hummer: H3 (08-10)
- Saab: 9-7X (06-09)
Frequently Asked Questions
Does this module really not require a trip to the dealer?
That’s correct. We program the module using your vehicle’s VIN before shipping. This ensures it’s ready for installation right out of the box, with no additional programming or flashing required. It’s a true plug-and-play solution.
What is a core charge? Do I need to send my old part back?
There is no core charge for this part. You can keep your old module or dispose of it yourself, saving you the time and hassle of managing a core return.
Where is the TCM located on my 2007 Grand Prix?
On the 2006-2008 Pontiac Grand Prix, the Transmission Control Module is located in the engine bay, mounted to the lower air cleaner housing. You will need to remove the air filter box to access it.
What if my part number is slightly different?
This module, 24239926, interchanges with many other GM part numbers like 24252114, 24234503, and others. As long as your vehicle is on the compatibility list and uses a T42-style TCM, this pre-programmed unit will work for your application.
What kind of warranty is included?
We stand behind our products with a one-year, hassle-free warranty. This covers any defects in the module, giving you peace of mind with your purchase.