Restore Your Pontiac’s Shifting Performance
Is your 2006-2008 Pontiac Grand Prix suffering from harsh shifts, delayed gear engagement, or getting stuck in limp mode? These are classic signs of a failing Transmission Control Module (TCM). After more than two decades in auto repair, I’ve seen countless GM vehicles sidelined by faulty TCMs. The electronics, often located in high-heat engine bays, eventually succumb to thermal stress, leading to unpredictable and unsafe driving conditions. This isn’t just an annoyance; it’s a critical failure that impacts your car’s reliability and fuel economy.
This replacement T42 TCM, part number 24235754, is the definitive solution. We take the guesswork and high cost out of the repair by pre-programming the module to your vehicle’s specific VIN. This means it arrives ready for a true plug-and-play installation, eliminating the need for an expensive trip to the dealership for programming. You’re not just buying a part; you’re buying a complete, hassle-free fix that restores the smooth, decisive shifting you expect from your Grand Prix.
Case Study: A Tricky Diagnosis
A customer brought in a 2007 Grand Prix with an intermittent no-shift condition and a persistent P0700 code. The issue only happened after driving for 30+ minutes, making it a nightmare to diagnose. After checking the wiring and solenoids, we focused on the TCM. Located under the air cleaner housing, it was getting baked by engine heat. On the bench, the module tested fine when cool, but a heat gun revealed the internal failure. We installed one of our VIN-programmed TCMs, and the problem was solved permanently. The customer avoided hundreds in diagnostic fees and dealership programming costs.
Is Your Grand Prix Showing These Telltale Signs?
A failing TCM will give you clear warnings. If you’re experiencing any of the following, it’s time to consider a replacement 2006-2008 Grand Prix TCM:
- ✔️ Abrupt, harsh, or slamming gear changes.
- ✔️ The vehicle feels stuck in one gear (often 2nd or 3rd) and won’t shift up or down.
- ✔️ Check Engine Light or Transmission Warning Light is illuminated on the dash.
- ✔️ Diagnostic Trouble Codes (DTCs) are present, such as P0700 (Transmission Control System Malfunction) or various solenoid-specific codes (e.g., P0750-P0758).
- ✔️ A noticeable drop in fuel efficiency or signs of the transmission overheating.
- ✔️ Complete loss of communication with the transmission module.
A Straightforward Guide to Installation
For the 2006-2008 Pontiac Grand Prix, this is a job most DIYers can handle in their own driveway in under an hour. Our pre-programmed 2006-2008 Grand Prix TCM makes it simple.
- Safety First: Disconnect the negative terminal from your vehicle’s battery to prevent electrical shorts and help reset the system.
- Locate the TCM: On your Grand Prix, the TCM is found underneath the lower air cleaner housing. You will need to remove the airbox assembly to gain access.
- Disconnect and Remove: Carefully unplug the electrical connectors from the old module. Press the release tabs firmly. 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.
- Reassemble and Reconnect: Reinstall the air cleaner housing and reconnect the negative battery terminal.
- Final Steps: Start the vehicle. While not always necessary, it’s good 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 the shifting issues are resolved.
Verified Fitment for Your Vehicle
This module is a direct-fit replacement for the following vehicles and configurations:
- Pontiac Grand Prix: 2006, 2007, 2008 (Transmission; located under the lower air cleaner housing)
This T42 TCM is also compatible with a wide range of other GM vehicles. Please verify your part number (24235754) or contact our expert support team to ensure perfect fitment for your specific car, truck, or SUV.
What does a Transmission Control Module (TCM) do?
What does a Transmission Control Module (TCM) do?
The TCM is the ‘brain’ of your automatic transmission. It receives data from various sensors on the engine and vehicle, and uses this information to control shift points, torque converter lockup, and line pressure. A failing TCM leads directly to the poor shifting performance you’re experiencing.
Is this module truly plug-and-play?
Yes. We program the module with your car’s Vehicle Identification Number (VIN) before shipping. This ensures it communicates perfectly with your vehicle’s other computers (like the ECM) right out of the box, with no dealership programming required.
Where is the TCM located on my 2006-2008 Grand Prix?
On the 2006-2008 Pontiac Grand Prix, the TCM is mounted underneath the air cleaner box assembly in the engine compartment. You’ll need to remove the airbox to access it.
Will this fix a P0700 trouble code?
A P0700 code is a general fault code indicating the TCM has detected a problem. While a faulty TCM is a very common cause, this code can also be triggered by other issues like bad solenoids or wiring. However, if you’re also experiencing erratic shifting, replacing a faulty 2006-2008 Grand Prix TCM is often the correct repair.
Is there a core charge for my old part?
No, there is no core charge. You are not required to send your old, faulty module back to us, saving you time and return shipping costs.