If your 2006-2011 Buick Lucerne is suffering from harsh shifting, delayed gear engagement, or has suddenly gone into limp mode, you’re likely dealing with a failing Transmission Control Module (TCM). As a technician with over two decades of experience, I’ve seen firsthand how a faulty TCM can cripple an otherwise perfectly good vehicle. This isn’t just an annoyance; it’s a critical failure that compromises your car’s performance and safety. This T42 series TCM, part number 24238856, is the definitive, reliable solution to restore the smooth, responsive shifting your Buick was designed for.
The biggest hurdle with electronic module replacement has always been the expensive and time-consuming trip to the dealership for programming. We eliminate that step entirely. By providing us with your vehicle’s VIN during checkout, we program the module with the latest GM software updates specifically for your Lucerne. This means it arrives at your door ready for a true plug-and-play installation, saving you hundreds of dollars and significant downtime. This isn’t just a part; it’s a complete, hassle-free repair solution.
A Technician’s Notebook: The Intermittent Lucerne
A customer brought in an ’08 Lucerne with a complaint that was driving them crazy: intermittent, bone-jarring shifts, but only after the car was fully warmed up. They’d been to two other shops that couldn’t replicate the issue. When I pulled the codes, I saw a history of P0700 (Transmission Control System Malfunction) and some intermittent solenoid circuit faults. Instead of throwing parts at it, we monitored live data. We saw that the TCM was commanding gears correctly, but the output signals were dropping out randomly once the module reached operating temperature. The internal electronics were failing under heat soak. We installed a VIN-programmed 2006-2011 Lucerne Transmission Module, and the problem was solved permanently. It’s a classic failure mode for these T42 modules.
Is Your Buick Exhibiting These Symptoms?
A failing TCM will give you clear warning signs. If you’re experiencing any of the following, it’s time to consider a replacement:
- âś” Harsh, slamming, or erratic gear changes.
- âś” The vehicle is stuck in a single gear (limp mode).
- âś” Check Engine Light or Transmission Warning Light is on.
- âś” Diagnostic Trouble Codes (DTCs) like P0700, P0750, P0751, or other solenoid-related faults are present.
- âś” Delayed engagement when shifting from Park to Drive or Reverse.
- âś” Poor fuel economy and a feeling of sluggishness.
- âś” Complete loss of communication with the transmission module.
Plug-and-Play Installation: Get Back on the Road Fast
This is a repair you can confidently tackle in your own garage. The 2006-2011 Lucerne Transmission Module is located in the engine compartment on the driver’s side, making it easily accessible. The entire process typically takes less than 30 minutes.
- Safety First: Disconnect the negative terminal from your vehicle’s battery to prevent any electrical shorts and to help reset the system.
- Locate the Module: On the Lucerne, you’ll find the TCM in the left-hand (driver’s side) of the engine compartment.
- Disconnect and Remove: Carefully unplug the electrical connectors. Note the locking tabs to avoid damage. Then, unbolt the module from its mounting bracket.
- Install the New Module: Bolt the new, pre-programmed module into place and securely reconnect the electrical harnesses.
- Final Steps: Reconnect the battery terminal. While the module is pre-programmed, it’s always best practice to use a basic OBD2 scan tool to clear any stored fault codes from other modules. Start the vehicle and enjoy your restored transmission performance.
Verified Vehicle Compatibility
While this listing is tailored for the Buick Lucerne, this T42 TCM is a direct replacement for a wide range of General Motors vehicles. It is interchangeable with part numbers 24252114, 24234503, 24230461, 24234274, 24235340, 24235754, 24238856, 24239224, and more. It fits models including:
- Buick Lucerne (2006-2011), LaCrosse (2006-2009)
- Chevrolet Impala (2006-2011), Silverado, Tahoe, Suburban (2007-2013)
- GMC Sierra, Yukon, Savana (2007-2014)
- Cadillac DTS (2006-2011)
- Pontiac G6, Grand Prix
- And many other GM cars, trucks, and SUVs from 2006-2014.
Frequently Asked Questions
Do I need to send my old part back? (Core Charge)
No. We do not require a core return for this module. You can keep your old part, which saves you the time, hassle, and expense of shipping it back.
Where do I find my VIN?
Your 17-digit Vehicle Identification Number (VIN) can be found on the driver’s side of the dashboard (visible through the windshield), on the driver’s side door jamb sticker, or on your vehicle’s registration and insurance documents.
Is any other programming needed after installation?
No. The module comes fully programmed to your VIN and is ready for installation right out of the box. No further dealer programming or special tools are required.
Will this fix my specific transmission problem?
This module is the direct solution for failures internal to the TCM itself, which cause the symptoms listed above. If your vehicle has a mechanical issue within the transmission (like a burnt clutch pack) or a wiring problem, this will not resolve it. Proper diagnosis is key.
What is the warranty on this part?
This transmission control module comes with a one-year warranty, giving you peace of mind and confidence in your repair.