Restore Smooth, Reliable Shifting to Your 2006-2008 Pontiac Grand Prix
If you’re battling with unpredictable shifting, a check engine light, or your Grand Prix going into limp mode, you’re not just dealing with an annoyance—you’re facing a common failure of the Transmission Control Module (TCM). As a technician with over two decades of experience, I’ve seen how a faulty TCM can sideline an otherwise great car. This VIN-programmed T42 Transmission Control Module, part number 24240400, is the definitive, hassle-free solution to get your Pontiac driving like new again, without a costly trip to the dealership for programming.
From the Diagnostic Bay
I remember a 2007 Grand Prix that came into the shop with a frustratingly intermittent problem. The owner said it would shift perfectly for days, then suddenly start banging into gear and throw a P0700 code. We checked the fluid, wiring, and solenoids—everything looked fine. On a hunch, we swapped in a known-good TCM. The problem vanished instantly. These T42 modules, especially after years of heat cycles under the hood, can develop internal faults that cause these phantom issues. Replacing it isn’t just a repair; it’s peace of mind.
Is Your Grand Prix Showing These Transmission Warning Signs?
A failing TCM doesn’t always mean a complete transmission failure. Often, it presents as a series of electronic gremlins. Here’s what to look for:
- âś” Harsh, slamming, or delayed gear shifts.
- âś” The vehicle gets stuck in a single gear (limp mode), often 2nd or 3rd.
- âś” An illuminated Check Engine Light or Transmission Warning Light.
- âś” Diagnostic Trouble Codes (DTCs) stored, such as the generic P0700 (Transmission Control System Malfunction) or specific solenoid codes like P0750-P0758.
- âś” Inability to upshift or downshift correctly, leading to poor acceleration and bad fuel economy.
- âś” Complete loss of communication with the module, preventing the vehicle from starting or shifting out of Park.
Your 30-Minute Path to a Smooth Ride
One of the best features of this module is its straightforward installation. For the 2006-2008 Grand Prix, the process is simple enough for a confident DIYer with basic tools. Because we program it to your VIN before shipping, you can skip the dealership entirely.
- Safety First: Disconnect the negative terminal from your vehicle’s battery to prevent any electrical shorts and help reset the system.
- Locate the Module: On your Grand Prix, the TCM is typically found under the lower air cleaner housing in the engine bay. You will need to remove the airbox assembly to access it.
- Disconnect and Remove: Carefully unplug the electrical connectors from the old TCM. Then, unbolt the module from its mounting bracket.
- Install the New Module: Bolt the new, pre-programmed TCM into place and securely reconnect the electrical harnesses. You should hear a click as they lock in.
- Final Steps: Reinstall the air cleaner housing and reconnect the battery. While the module is plug-and-play, it’s always good practice to use a basic scan tool to clear any lingering fault codes from the computer’s memory.
Verified Vehicle Compatibility
This module is a direct-fit replacement for the 2006-2008 Pontiac Grand Prix. It is also a compatible replacement for a wide range of other GM vehicles, ensuring OEM-level function and reliability. This part is interchangeable with the following part numbers: 24252114, 24234503, 24230461, 24234274, 24235340, 24235754, 24238856, 24239224, 24239926, 24240400, 24241806, 24243901, 24243921, 24252114, 24255280, 24256960, 24235732, 24235753, 24240449, and YNXS.
Frequently Asked Questions
What does ‘VIN Programmed’ mean for me?
It means we load your vehicle’s specific Vehicle Identification Number (VIN) and the latest GM software onto the module before we ship it. This ensures it communicates perfectly with your car’s engine computer and other systems right out of the box, eliminating the need for expensive dealership programming.
Is this a difficult part to install on my Grand Prix?
No, for someone with basic mechanical skills, it’s a very manageable job. The TCM is located under the air cleaner box. The entire process typically takes less than 30 minutes.
Will this fix my P0700 check engine light code?
If the code is being caused by a faulty TCM, then yes. A P0700 is a general code indicating a fault in the transmission control system. A failing TCM is one of the most common root causes. After installation, be sure to clear the codes with a scan tool.
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, saving you the time and hassle of a return shipment.
What kind of warranty is included?
This module comes with a one-year warranty, giving you confidence and protection for your repair.