If your 2006-2011 Buick Lucerne is suffering from erratic shifting, getting stuck in gear, or has an illuminated check engine light 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). This isn’t just an annoyance; it’s a critical failure that compromises your car’s performance and reliability. This T42 TCM, interchangeable with part number YNXS, is the definitive, hassle-free solution to restore the smooth, predictable operation you expect from your Buick.
The biggest hurdle in replacing a TCM has always been the need for expensive, time-consuming dealership programming. We eliminate that step entirely. By providing your vehicle’s VIN at checkout, we program the module with the latest GM software specific to your Lucerne. It arrives at your door ready for a true plug-and-play installation, saving you hundreds of dollars and significant downtime. This is the exact approach I take in my own shop to guarantee a successful repair the first time.
Case Study: A Tricky Diagnosis
A customer brought in an ’08 Lucerne with a complaint of intermittent, harsh 1-2 shifts and occasionally getting stuck in 3rd gear (limp mode), but only after driving for 20+ minutes. They’d already replaced two shift solenoids at another shop with no success. After a quick scan, I saw the familiar P0700 (Transmission Control System Malfunction) code. Instead of just chasing solenoid codes, I monitored the TCM data stream. I noticed the module’s internal temperature readings were spiking just before the shifting issues occurred—a classic sign of internal electronic failure. We installed a VIN-programmed T42 TCM, and the problem was solved instantly. The issue wasn’t the transmission’s mechanical parts, but the computer controlling them.
Is Your Lucerne Exhibiting These Transmission Faults?
A failing TCM can manifest in several ways. If you’re experiencing any of the following, this module is the likely solution for your 2006-2011 Lucerne TCM issues:
- ✔ Harsh, delayed, or unpredictable gear shifts.
- ✔ Vehicle enters ‘limp mode,’ often stuck in a single gear (like 2nd or 3rd).
- ✔ Check Engine Light or Transmission Warning Light is on.
- ✔ Diagnostic Trouble Codes (DTCs) are present, such as P0700, P0750-P0758, or other solenoid-related faults.
- ✔ Complete failure to shift up or down.
- ✔ A noticeable drop in fuel economy due to inefficient shifting.
- ✔ The torque converter fails to lock up at highway speeds.
Your 30-Minute Path to a Smooth Ride
Replacing the TCM on your Lucerne is a straightforward job that most DIY enthusiasts can complete in their own driveway. No specialized tools are required.
- Safety First: Always disconnect the negative terminal from your vehicle’s battery before starting any electronic component replacement. This prevents electrical shorts and helps reset the vehicle’s systems.
- Locate the Module: On the Buick Lucerne, the TCM is typically found in the engine compartment, mounted to the left-hand (driver’s side) inner fender or near the air cleaner housing.
- Disconnect and Remove: Carefully unclip the wiring harness connectors. Then, unbolt the old module from its mounting bracket. There are usually two or three small bolts holding it in place.
- Install the New Module: Bolt your new, pre-programmed TCM into place and securely reconnect the wiring harnesses. Ensure they click into place.
- Final Steps: Reconnect the battery terminal. Start the vehicle and allow it to idle for a few minutes. While our programming handles the critical setup, it’s good practice to use a basic OBD2 scan tool to clear any stored fault codes to ensure a clean slate.
Verified Compatibility for Your GM Vehicle
This T42 TCM is a direct-fit replacement for a wide range of General Motors vehicles. While this page focuses on the 2006-2011 Lucerne TCM, it is also compatible with the following models and years. Please confirm your specific application.
- Buick: Lucerne (2006-2011), LaCrosse (2006-2009), Allure (2006-2009), Rainier (2006-2007), Rendezvous (2006-2007)
- Chevrolet: Silverado, Tahoe, Suburban, Avalanche (2007-2013), Impala (2006-2011), Monte Carlo (2006-2007), HHR (2006-2011), Cobalt (2006-2010), Express Van (2006-2014), Colorado (2008-2012)
- GMC: Sierra, Yukon, Savana Van (2006-2014), Canyon (2008-2012), Envoy (2006-2009)
- Pontiac: G6 (2006-2010), Grand Prix (2006-2008)
- Cadillac: DTS (2006-2011)
- And more, including select Saturn, Hummer, and Saab models.
Frequently Asked Questions
What does ‘VIN Programmed’ actually mean for me?
It means the module arrives ready for installation with no extra steps. We load the software specific to your car’s Vehicle Identification Number (VIN) before shipping. This ensures it communicates perfectly with your engine computer and other systems, avoiding the need for a trip to the dealership for expensive programming.
Is this a difficult part to install myself?
Not at all. For most DIYers with basic hand tools, this is a job that takes less than 30 minutes. The module is easily accessible in the engine bay, and the process involves simply unplugging the old one and plugging in the new one.
Will this part fix a P0700 code?
A P0700 code is a general fault code indicating the TCM has detected a problem. In many cases, the problem is the TCM itself. If your diagnosis points to a failed module, replacing it with this part is the correct fix to clear the P0700 and any related transmission codes.
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, which simplifies the process for you.
What if I have a different part number on my original module?
This T42 TCM, part YNXS, is a service replacement for many original part numbers, including 24242391, 24234503, and 24252114, among others. As long as your vehicle is on the compatibility list, this module will function correctly once programmed to your VIN.