Is Your Buick LaCrosse Shifting Erratically?
If you’re experiencing harsh shifting, delayed gear engagement, or your 2006-2009 Buick LaCrosse 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, managing torque converter lockup, and monitoring system health. 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. Don’t let a faulty module sideline your vehicle. This OEM-quality T42 TCM, service part number 24252114, is the definitive solution to restore your transmission’s smooth, reliable performance.
From the Diagnostic Bay
We had a 2008 GMC Sierra in the shop with a classic complaint: ‘it just doesn’t know what gear to be in.’ The customer reported intermittent hard shifts, especially from 1st to 2nd, and the check engine light would pop on and off. Scans showed a generic P0700 transmission fault code and a specific code for a shift solenoid circuit. After testing the solenoid and wiring, which checked out fine, we focused on the T42 TCM. These modules are known for developing internal faults that cause intermittent signal loss to the solenoids. We installed one of our VIN-programmed T42 modules, cleared the codes, and the truck shifted perfectly on the test drive. The customer called a week later to say it was driving better than it had in years. It’s a common story, and a new, properly programmed TCM is almost always the fix.
The Ultimate Solution: A Pre-Programmed 2006-2009 LaCrosse TCM
Replacing a TCM used to mean a trip to the dealership for expensive and time-consuming programming. Our process eliminates that hassle entirely. We pre-program this T42 module to your vehicle’s specific Vehicle Identification Number (VIN) before it ships. This ensures that it arrives ready for a true plug-and-play installation. The module will have the latest GM software updates, ensuring optimal communication with your vehicle’s other computers and correcting common factory software bugs that may have contributed to the initial failure. This isn’t just a replacement part; it’s a direct-fit component designed to restore factory performance and reliability.
Symptoms of a Failing GM T42 TCM
- ✔ Erratic and Harsh Shifting: Your transmission may bang into gear, hesitate, or shift at the wrong times.
- ✔ Stuck in Gear / Limp Mode: The vehicle may refuse to shift out of a single gear (often 2nd or 3rd) to prevent further damage.
- ✔ Warning Lights: The Check Engine Light or a specific transmission warning light will illuminate on your dashboard.
- ✔ Diagnostic Trouble Codes (DTCs): You’ll often see codes like P0700 (Transmission Control System Malfunction) or various solenoid-specific codes (P0751, P0756, etc.).
- ✔ Poor Fuel Economy: Inefficient shifting and torque converter operation can lead to a noticeable drop in MPG.
- ✔ No Communication: In severe cases, a scan tool may be unable to communicate with the TCM at all.
Installation and Compatibility
Installation is straightforward for the mechanically inclined. On the 2006-2009 Buick LaCrosse, the TCM is typically located under the lower air cleaner housing, making it accessible from the engine bay. The process involves disconnecting the battery, unplugging the electrical connectors from the old module, unbolting it, and installing the new one in its place. Once the new module is connected and the battery is reconnected, the vehicle is ready to go. While the VIN programming handles the critical setup, we recommend using a basic scan tool to clear any stored historical codes from the Engine Control Module (ECM) after installation.
This versatile T42 module is not only the correct part for your Buick LaCrosse but also fits a massive range of other General Motors vehicles equipped with 4-speed automatic transmissions like the 4L60E, 4L65E, and 4L70E. It is a direct replacement for numerous part numbers, including 24234503, 24230461, 24240400, and 24256960, among others. Whether you’re working on a Chevrolet Silverado, GMC Yukon, Cadillac DTS, or Pontiac G6, this module provides the same level of quality and reliability.
Frequently Asked Questions
What does a ‘VIN-programmed’ TCM mean?
It means we load your vehicle’s specific factory software and settings onto the module using your VIN before we ship it. This makes the module recognize your vehicle’s engine, tire size, and other options, allowing for a simple plug-and-play installation without needing a trip to the dealer for programming.
Will this fit vehicles other than the 2006-2009 Buick LaCrosse?
Yes, absolutely. This T42 TCM is compatible with dozens of GM models from roughly 2006 to 2014, including trucks, vans, and cars like the Chevrolet Tahoe, GMC Sierra, Saturn Vue, and Pontiac Grand Prix. Please check the detailed fitment list on this page to confirm for your specific vehicle.
Do I need a special tool to install this module?
No special programming tools are required. Basic hand tools like a socket set and ratchet are all that’s needed for the physical installation. We do recommend having a basic OBD2 scan tool to clear any old fault codes from the system after the new part is installed.
What happens if I don’t replace a failing TCM?
Continuing to drive with a faulty TCM can lead to more severe transmission damage. Poor shifting can cause excessive wear on clutches and bands, and incorrect fluid pressure can lead to overheating. This can turn a relatively simple electronics fix into a major mechanical repair.
Is there a core charge for this part?
No, there is no core charge. You are not required to send your old, faulty module back to us, saving you time and the hassle of return shipping.