Restore Your Pontiac’s Shifting Performance
Is your 2006-2008 Pontiac Grand Prix suffering from jarring shifts, getting stuck in gear, or throwing transmission codes? These are classic signs of a failing Transmission Control Module (TCM). The TCM is the electronic brain of your automatic transmission, responsible for every gear change and torque converter operation. When it fails, it can make your car feel unreliable and frustrating to drive. This replacement T42 TCM, part number 24255280, is the definitive solution to restore the smooth, predictable performance your Grand Prix once had.
Case Study: A Tricky Diagnosis
I remember a 2007 Grand Prix that came into my shop with a complaint of intermittent harsh 1-2 shifts and occasionally getting stuck in 3rd gear (limp mode). The owner had already replaced a couple of shift solenoids based on the codes, but the problem persisted. A quick scan showed a P0700 (Transmission Control System Malfunction) and an intermittent solenoid circuit code. After 20 years of diagnostics, I know that when direct solenoid replacement doesn’t fix the issue, the fault often lies with the driver circuit inside the TCM. The module’s internal electronics had become weak, unable to consistently command the solenoids. We installed a VIN-programmed T42 module, and the car’s shifting was immediately crisp and correct. This part saved the customer from a costly transmission rebuild they didn’t need.
Is Your Grand Prix Showing These Telltale Signs?
- ✔ Harsh, banging, or erratic gear shifts.
- ✔ The vehicle is stuck in a single gear (often called “limp mode”).
- ✔ Check Engine Light is on with transmission-related Diagnostic Trouble Codes (DTCs), such as P0700, P0750, or other solenoid-specific codes.
- ✔ Delayed engagement when shifting from Park to Drive or Reverse.
- ✔ A noticeable drop in fuel economy due to inefficient shifting.
- ✔ Complete loss of communication with the transmission module.
The Definitive Solution for Your 2006-2008 Grand Prix TCM
This isn’t just a replacement part; it’s a complete, ready-to-install solution. The biggest hurdle in replacing a modern TCM is the need for expensive dealership programming. We eliminate that step entirely. By providing your vehicle’s VIN at checkout, we program the module with the latest GM software specific to your Grand Prix. This ensures perfect communication between the engine and transmission, correct shift points, and proper torque converter lockup strategy from the moment you install it. It’s a professional-grade repair you can confidently perform in your own garage.
DIY-Friendly Installation in Under 30 Minutes
- ✔ Safety First: Disconnect the negative terminal from your vehicle’s battery to prevent electrical shorts and reset the system.
- ✔ Locate the Module: On the 2006-2008 Grand Prix, the TCM is conveniently located inside the lower air cleaner housing. You will need to remove the air filter box 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. Ensure they click into place.
- ✔ Reassemble and Reconnect: Reinstall the air cleaner housing and reconnect the negative battery terminal.
- ✔ Final Check: Start the vehicle and allow it to idle for a few minutes. If you have a basic scan tool, it’s good practice to clear any stored fault codes. Take a test drive to confirm smooth shifting.
Verified Vehicle Compatibility
While this is the direct replacement for the 2006-2008 Pontiac Grand Prix, this T42 TCM is also compatible with a wide range of other GM vehicles. Please verify your part number (24255280) or consult the list below. This module is interchangeable with part numbers 24242391, 24234503, 24252114, and others.
Partial Fitment List:
- Pontiac Grand Prix: 2006, 2007, 2008 (Transmission; lower air cleaner housing)
- Buick Allure / LaCrosse: 2006-2009 (Transmission; lower air cleaner housing)
- Chevrolet Impala / Monte Carlo: 2006-2011 (Transmission; lower air cleaner housing)
- Chevrolet Cobalt / Pontiac G5 / Saturn Ion: 2006-2010 (Transmission; LH strut tower)
- Chevrolet Silverado / GMC Sierra 1500: 2007-2013 (Transmission; next to battery)
- Chevrolet Tahoe / GMC Yukon: 2007-2009 (Transmission; next to battery)
- …and many more GM models from 2006-2014.
Frequently Asked Questions
Do I need to take my car to the dealer after installing this?
No. This module comes fully programmed to your vehicle’s VIN. It is a true plug-and-play solution, requiring no additional dealership programming or expensive tools.
Is this a new or used part?
This is a high-quality, OEM-spec component that has been expertly tested and programmed. It is backed by our one-year warranty for your peace of mind.
What tools do I need for the installation?
For a Pontiac Grand Prix, you will typically only need basic hand tools, such as a socket set and a screwdriver, to remove the air cleaner assembly and unbolt the module. No special electronic tools are required.
Will this fix my P0700 check engine light code?
Yes, if the code is being caused by a faulty TCM. A P0700 is a general code indicating a fault within the transmission control system. This module is the most common solution for this and related solenoid codes when the solenoids themselves are good.
Do I need to send my old part back?
No, there is no core charge for this module. You can keep or dispose of your old part without any hassle.