If your 2006-2008 Pontiac Grand Prix is suffering from erratic shifting, getting stuck in gear, or has the check engine light on with transmission codes, you’ve come to the right place. As a technician with over two decades of experience, I’ve seen countless GM vehicles sidelined by a faulty Transmission Control Module (TCM). The T42 module, like this part number 24235732, is the brain of your automatic transmission, and when it fails, it can cause a cascade of frustrating and potentially damaging problems. This isn’t just a part; it’s the solution to restoring the smooth, reliable performance you expect from your car.
We take the guesswork and high cost out of the repair. Unlike the dealership, which requires expensive programming after installation, this module arrives at your door pre-programmed to your vehicle’s specific VIN. This ensures perfect communication between the engine and transmission, optimizing shift points, torque converter lockup, and fuel efficiency right out of the box. It’s a direct-fit, plug-and-play fix designed for both professional mechanics and determined DIYers.
From the Diagnostic Bay
I remember a 2007 Grand Prix that came into the shop with a classic complaint: ‘It bangs into gear sometimes, and other times it feels like it’s slipping.’ The owner had already replaced a shift solenoid with no luck. A quick scan showed a P0700 (Transmission Control System Malfunction) and an intermittent solenoid circuit code. After 20 years of diagnostics, I know that intermittent electrical faults often point back to the module itself. Heat cycles and vibrations can cause internal solder joints in the TCM to fail. We installed a VIN-programmed T42 module, and the car drove off shifting like it just left the factory. It’s often the brain, not the muscle, that’s the issue.
Is Your Grand Prix Showing These Red Flags?
A failing TCM will give you clear warning signs. If you’re experiencing any of the following, a new module is the most likely solution for your 2006-2008 Grand Prix TCM issues:
- âś” Harsh, slamming shifts or delayed gear engagement.
- âś” The vehicle is stuck in “limp mode,” usually in 2nd or 3rd gear.
- âś” An illuminated Check Engine Light or Transmission Warning Light.
- âś” Diagnostic Trouble Codes (DTCs) stored, such as P0700, P0750-P0758, or other transmission-related faults.
- âś” Failure to upshift or downshift properly, leading to poor acceleration.
- âś” A noticeable drop in fuel economy or signs of the transmission overheating.
A Straightforward 30-Minute Installation Guide
Replacing the TCM on your Grand Prix is a job you can tackle in your own driveway. No specialized tools are needed. For the 2006-2008 Grand Prix, you’ll find the TCM located under the lower air cleaner housing.
- Safety First: Always disconnect the negative terminal from your vehicle’s battery before starting any electrical work.
- Access the Module: Remove the air cleaner assembly to gain clear access to the old TCM.
- Disconnect and Remove: Carefully unplug the electrical connectors from the module. Then, unbolt the module from its mounting bracket.
- Install the New Module: Bolt the new VIN-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 assembly and reconnect the battery. Start the vehicle and allow it to idle for a few minutes. While not always necessary, using a basic scan tool to clear any old codes is a good final step.
Verified Fitment for Your Vehicle
This T42 Transmission Control Module is a direct replacement for part number 24235732 and other interchangeable numbers. It is guaranteed to fit the following models:
- Pontiac Grand Prix: 2006, 2007, 2008 (Transmission; located in lower air cleaner housing)
This module also fits a wide range of other GM vehicles including the Impala, Monte Carlo, LaCrosse, Allure, and more. Please verify your part number or contact us with your VIN to ensure perfect compatibility.
Frequently Asked Questions
Frequently Asked Questions
Do I need to take my car to the dealer for programming?
No. This module is delivered fully programmed to your vehicle’s VIN. It is a true plug-and-play solution, saving you the time and expense of a dealership visit.
What is a T42 TCM?
The T42 is the specific hardware generation of Transmission Control Module used by General Motors in many of its 4-speed automatic transmissions from the mid-2000s, including the 4L60E and 4L65E found in your Grand Prix.
Will this fix a P0700 trouble code?
A P0700 code is a general fault request from the TCM to the main engine computer (ECM) to turn on the check engine light. In many cases where the TCM itself has failed, replacing it with this programmed module will resolve the root cause and allow the code to be cleared.
Is there a core charge for my old part?
No, there is no core charge. You can keep your old module or dispose of it without the hassle of returning it.