Restore Your Grand Prix’s Shifting Performance
Is your 2006-2008 Pontiac Grand Prix suffering from unpredictable shifting, getting stuck in gear, or throwing transmission codes? You’re not alone. The Transmission Control Module (TCM) is the brain of your automatic transmission, and when it fails, it can cause a host of frustrating and potentially unsafe driving conditions. This T42 Transmission Control Module, part number 24235340, is the definitive solution. As an experienced technician, I’ve seen these modules resolve countless drivability issues. We pre-program this module to your vehicle’s specific VIN, ensuring it works perfectly right out of the box—no expensive trip to the dealership required.
A Technician’s Notebook: The Misleading Solenoid Code
A customer brought in a 2007 Grand Prix with a classic complaint: harsh 1-2 shifts and a check engine light. The scanner pulled a P0752 code, pointing to a stuck shift solenoid. The customer had already replaced the solenoid themselves, but the problem persisted. This is a scenario I’ve diagnosed hundreds of times. While the code points to a solenoid, the root cause is often the TCM itself. Heat cycles and vibrations cause internal solder joints to fail, leading to faulty commands being sent to perfectly good solenoids. We installed a VIN-programmed T42 TCM, cleared the codes, and the car shifted like new. It’s a prime example of why correctly diagnosing the electronic controller is key to avoiding wasted time and money on unnecessary internal transmission work.
Is Your Grand Prix Showing These Symptoms?
A faulty TCM can manifest in several ways. If you’re experiencing any of the following, it’s a strong indicator that your 2006-2008 Grand Prix TCM needs replacement:
- ✔ Harsh, banging, or erratic gear shifts.
- ✔ The vehicle feels stuck in one gear (often called “limp mode”).
- ✔ Delayed engagement when shifting from Park to Drive or Reverse.
- ✔ Check Engine Light or Transmission Warning Light is illuminated.
- ✔ Diagnostic Trouble Codes (DTCs) are present, such as P0700, P0750, or other solenoid-related codes.
- ✔ Poor acceleration and decreased fuel economy.
- ✔ Complete loss of communication with the transmission module.
Your 30-Minute Path to Smoother Shifts
For the Pontiac Grand Prix, this is a straightforward job that most DIYers can complete in their driveway. No special tools are needed, and our VIN programming means the most complex part is already done for you.
- Safety First: Always disconnect the negative terminal from your car’s battery before starting any electronic component replacement.
- Locate the TCM: On your 2006-2008 Grand Prix, you’ll find the TCM located under the lower air cleaner housing in the engine bay.
- Disconnect and Remove: Carefully unplug the electrical connectors from the old module. Then, unbolt the module from its mounting bracket and remove it from the vehicle.
- Install the New Module: Mount the new, pre-programmed TCM in place and tighten the bolts. Reconnect the electrical harnesses securely.
- Final Steps: Reconnect the battery terminal. While the module is plug-and-play, it’s best practice to use a basic OBD2 scan tool to clear any stored fault codes from the vehicle’s memory. Take the car for a test drive to confirm smooth operation.
Verified Vehicle Compatibility
This T42 TCM is a direct-fit replacement for a wide range of General Motors vehicles. While this page focuses on the 2006-2008 Grand Prix TCM, it is also compatible with the following models. Please verify your specific vehicle and the location notes.
- Pontiac Grand Prix: 2006-2008 (located in lower air cleaner housing)
- Chevrolet Impala: 2006-2011 (lower air cleaner housing)
- Chevrolet Monte Carlo: 2006-2007 (lower air cleaner housing)
- Buick Allure: 2006-2009 (lower air cleaner housing)
- Buick LaCrosse: 2006-2009 (lower air cleaner housing)
- Chevrolet Silverado & GMC Sierra Trucks: 2007-2013 (next to battery)
- Chevrolet Tahoe, Suburban, Avalanche & GMC Yukon: 2007-2009 (next to battery)
- …and many other GM models listed in the original fitment chart.
This module replaces part numbers: 24252114, 24234503, 24230461, 24234274, 24235340, 24235754, 24238856, 24239224, and more.
Frequently Asked Questions
Do I need to have this module programmed by a dealer?
No. We handle all the programming for you. Simply provide your vehicle’s VIN at checkout, and the module will arrive ready for plug-and-play installation.
What is a core charge?
A core charge is a deposit you pay until you return your old part. We do not have a core charge on this item, so you can keep your old module without any hassle.
Will this fix a P0700 trouble code?
A P0700 is a generic code indicating the TCM has detected a fault. In many cases, replacing a faulty TCM will resolve the P0700 and any related specific codes (like for solenoids or sensors). However, you should always ensure the wiring and transmission itself are in good condition.
Is this a difficult part to install on my Grand Prix?
No, for most individuals with basic mechanical skills, this is a very manageable repair. The module is accessible under the air cleaner box, and the process typically takes less than 30 minutes.
What happens if I install it and still have issues?
Our modules are backed by a one-year warranty and expert support. If problems persist, it could indicate an issue elsewhere in the system, such as wiring or an internal transmission component. Our team is here to help you diagnose the situation.