Restore Smooth and Reliable Shifting to Your Buick Lucerne
If your 2006-2011 Buick Lucerne is suffering from erratic shifting, hesitation, or has a check engine light pointing to a transmission issue, the problem is very likely a failing Transmission Control Module (TCM). As a technician with over two decades of experience, I’ve seen how a faulty TCM can make a comfortable luxury sedan like the Lucerne feel unpredictable and unsafe. This replacement T42 TCM, part number 24239926, is the definitive solution to restore your vehicle’s performance and your peace of mind.
The TCM is the electronic brain of your automatic transmission. It processes data from various sensors to command precise gear changes and ensure efficient operation. When it fails, the symptoms can range from annoying to dangerous. Our module is a direct-fit replacement, but with a crucial benefit: it comes expertly programmed to your car’s specific Vehicle Identification Number (VIN). This means you can skip the costly and time-consuming trip to the dealership for programming. It’s a true plug-and-play fix designed for both professional installers and savvy DIY owners.
Case Study: A Tricky Diagnosis
A customer brought in a 2008 Lucerne with a frustrating, intermittent problem. It would shift perfectly for days, then suddenly start slamming into gear or refuse to shift out of 2nd. They’d been to two other shops that couldn’t find the issue because it never acted up for them. After hooking up my scan tool and monitoring live data during a long test drive, I noticed the TCM communication would drop out only after the engine bay was fully heat-soaked. The original module had developed an internal fracture that only separated when hot. We replaced it with one of our pre-programmed T42 modules, and the problem was solved instantly. This is a classic failure mode for these units, and this part is the reliable fix.
Is Your Buick Exhibiting These Transmission Woes?
A failing TCM will give you clear warning signs. If you’re experiencing any of the following, it’s time to consider a replacement:
- ✔ Harsh, slamming, or delayed gear shifts.
- ✔ The vehicle feels stuck in one gear (often called “limp mode”).
- ✔ Check Engine Light or Transmission Warning Light is on.
- ✔ Diagnostic Trouble Codes (DTCs) are present, such as P0700, P0750, P0753, P0758, or other solenoid-related faults.
- ✔ A noticeable decrease in fuel economy.
- ✔ The transmission seems to slip between gears or fails to engage properly from Park.
A Straightforward Guide to Installation
Replacing the TCM on your Lucerne is a job you can tackle in your own garage in under an hour with basic hand tools. This can save you hundreds in labor costs.
- Safety First: Disconnect the negative terminal from your vehicle’s battery to prevent any electrical shorts and to help reset the vehicle’s computer systems.
- Locate the Module: On the 2006-2011 Buick Lucerne, the TCM is conveniently located in the engine compartment on the driver’s side (LH side), making access easy.
- Disconnect and Remove: Carefully unplug the electrical connectors from the old TCM. Then, unbolt the module from its mounting bracket and remove it from the vehicle.
- Install the New Module: Mount your new, pre-programmed TCM in the same location and securely fasten it. Reconnect the electrical connectors, ensuring they click into place.
- Final Steps: Reconnect the negative battery terminal. While our programming handles the critical setup, it’s good practice to use a basic OBD2 scan tool to clear any stored fault codes from the ECU. Start the car and enjoy your smooth-shifting transmission!
Verified Vehicle Compatibility
This Transmission Control Module is a guaranteed fit for the following Buick Lucerne models. It is also compatible with a wide range of other GM vehicles that use the T42 TCM.
- Buick Lucerne 2006-2007 (with 4.6L V8 engine, located in LH engine compartment)
- Buick Lucerne 2008-2011 (all engines, located in LH engine compartment)
This module also interchanges with part numbers: 24252114, 24234503, 24230461, 24234274, 24235340, 24235754, 24238856, 24239224, 24240400, and more.
Frequently Asked Questions
Frequently Asked Questions
What does ‘VIN Programmed’ mean for me?
It means the module arrives ready for installation. We load your car’s specific VIN and the latest GM software onto the module before we ship it. This allows you to install it yourself without needing a trip to the dealer for expensive programming, saving you time and money.
Where is the TCM on my 2006-2011 Buick Lucerne?
The Transmission Control Module on these Lucerne models is located in the engine bay, on the driver’s side (LH side), making it very accessible for replacement.
Do I need to return my old TCM?
No. There is no core charge for this part. You can keep your old module or dispose of it without any hassle or extra fees.
Will this part fix a P0700 trouble code?
A P0700 code is a general fault code indicating that the TCM has detected a problem and requested the check engine light. While this module won’t clear the P0700 itself, it is designed to fix the underlying specific transmission faults (like solenoid circuit errors) that cause the P0700 code to be set in the first place.
Are any special tools required for this installation?
No special tools are needed. The installation can be completed with a basic set of hand tools, such as a socket wrench and screwdrivers. A simple OBD2 scanner is recommended to clear any stored codes after installation, but is not always necessary.