Is Your 2006-2008 Pontiac Grand Prix Shifting Erratically?
If you’re experiencing harsh shifts, delayed gear engagement, or your Grand Prix is stuck in limp mode, a failing Transmission Control Module (TCM) is the most likely culprit. The TCM is the electronic brain of your automatic transmission, responsible for orchestrating every gear change and ensuring smooth, efficient operation. When it fails, it can cause a cascade of frustrating and potentially damaging issues, from poor fuel economy to a complete inability to shift gears. This VIN-programmed T42 TCM, part number 24241806, is the definitive solution to restore your vehicle’s performance and drivability.
The Brains Behind the Brawn: Understanding the T42 TCM’s Role
Your vehicle’s transmission is a complex mechanical system, but it relies on precise electronic commands to function correctly. The T42 TCM constantly analyzes data from various sensors, including vehicle speed, engine RPM, and throttle position. It uses this information to control hydraulic pressure, activate solenoids, and manage the torque converter clutch, ensuring you’re always in the right gear at the right time. A faulty module can misinterpret this data, leading to the common symptoms that plague drivers of many GM vehicles from this era, including the Pontiac Grand Prix.
From the Diagnostic Bay
We recently had a 2007 Grand Prix GXP come into the shop with the check engine light on and the transmission banging into gear. The owner complained it felt like he was being rear-ended every time it shifted from first to second. A scan revealed a generic P0700 transmission fault code along with a specific code for a shift solenoid circuit. After verifying the solenoid’s wiring and resistance were within spec, we suspected the driver circuit within the TCM itself had failed—a common issue. Instead of a costly and time-consuming diagnostic rabbit hole, we installed one of our VIN-programmed T42 modules. After a quick 20-minute installation under the air cleaner box and clearing the codes, the car shifted like it just rolled off the factory floor. The customer was thrilled to have his car back without a trip to the dealership.
Signs Your Grand Prix TCM is Failing
- ✔ Erratic and Harsh Shifting: Experiencing sudden, jerky, or unpredictable gear changes that make driving uncomfortable.
- ✔ Stuck in Gear or Limp Mode: The vehicle refuses to shift out of a single gear (often 2nd or 3rd) to protect the transmission from further damage.
- ✔ Warning Lights: The Check Engine Light or a specific transmission warning light is illuminated on your dashboard.
- ✔ Diagnostic Trouble Codes (DTCs): Common codes like P0700 (Transmission Control System Malfunction) or various solenoid-specific codes (P0750, P0751, etc.) are stored.
- ✔ Delayed Engagement: A noticeable pause when shifting from Park into Drive or Reverse.
- ✔ Poor Fuel Economy: Inefficient shifting and torque converter lockup issues can lead to a significant drop in gas mileage.
- ✔ No Communication: A scan tool may be unable to communicate with the TCM, indicating a complete module failure.
The Definitive Solution: A Pre-Programmed 2006-2008 Grand Prix TCM
Don’t settle for a generic, unprogrammed module that requires an expensive trip to the dealership for calibration. This T42 TCM arrives at your door pre-programmed to your vehicle’s specific Vehicle Identification Number (VIN). This critical step ensures complete compatibility with your Grand Prix’s engine, transmission, and other electronic systems. We load the latest GM software updates, which often correct factory flaws and improve transmission performance beyond its original state. This is a true plug-and-play solution designed for both professional technicians and DIY mechanics.
Installation and Compatibility
For the 2006-2008 Pontiac Grand Prix, the TCM is conveniently located under the lower air cleaner housing, making for a straightforward replacement. Simply disconnect the battery, remove the air cleaner assembly, unplug the electrical connectors from the old module, unbolt it, and install the new one in its place. Reconnect everything, and you’re ready to go. This module is a direct replacement for a wide range of part numbers, including 24252114, 24234503, 24241806, and many more, ensuring broad compatibility across the GM lineup. While this page focuses on the Grand Prix, this T42 TCM is also the correct part for dozens of other vehicles like the Chevrolet Impala, Buick LaCrosse, GMC Sierra, and Cadillac DTS.
Frequently Asked Questions
What does ‘VIN Programmed’ mean?
VIN programming means we flash the module with your vehicle’s specific software from GM before we ship it. This makes the part recognize your car’s unique configuration, allowing it to work perfectly right out of the box without any need for dealership tools or additional programming fees.
Do I need to send my old part back?
No, there is no core charge for this Transmission Control Module. You can keep your old part, recycle it, or dispose of it at your convenience. This saves you the time and expense of return shipping.
Is this a difficult part to install myself?
For most individuals with basic mechanical skills and tools, this is a very manageable job. On a 2006-2008 Grand Prix, it’s located under the air cleaner housing. The entire process typically takes less than an hour. Always remember to disconnect the battery’s negative terminal before starting any electrical work.
Will this fix my specific transmission problem?
This module is the solution for a wide array of electronic transmission faults, including harsh shifting, solenoid codes, and limp mode. If your mechanic has diagnosed a faulty TCM, this part is the correct fix. It resolves issues caused by internal electronic failure within the module itself.
What if my part number isn’t an exact match?
GM uses many different service numbers for the same T42 TCM. This part, 24241806, is interchangeable with numerous other numbers like 24252114 and 24234503. As long as your vehicle is listed in the compatibility chart and has a T42-style module, our VIN programming will ensure it works correctly.