Restore Your Buick’s Smooth Ride
If you’re dealing with the frustration of a Buick LaCrosse that shifts harshly, gets stuck in gear, or has a persistent check engine light, you’re not alone. As a technician with over two decades of experience, I’ve seen countless GM vehicles come into the bay with these exact issues. The culprit is often a failing Transmission Control Module (TCM). This isn’t just an annoyance; it affects your car’s performance, fuel economy, and safety. This T42 TCM, part number 24234274, is the definitive solution for your 2006-2009 Buick LaCrosse, designed to restore the crisp, reliable shifting you expect.
From the Diagnostic Bay: The Case of the Stubborn Limp Mode
A customer brought in their ’08 LaCrosse, stuck in what we call “limp mode”—it wouldn’t shift out of 3rd gear. They’d already replaced a shift solenoid based on a code, but the problem returned immediately. My scan tool pulled a P0700 (Transmission Control System Malfunction), a general code that points to a deeper issue. Experience told me to look at the TCM. After swapping in one of our VIN-programmed T42 modules, the car shifted perfectly. The initial solenoid code was just a symptom; the failing TCM was the root cause. This pre-programmed module saved the customer from another incorrect repair and a costly trip to the dealership.
Is Your Buick LaCrosse Showing These Telltale Signs?
A failing TCM doesn’t just die; it usually gives you warning signs. If you’re noticing any of the following, it’s time to consider a replacement to avoid more significant transmission damage. A new 2006-2009 LaCrosse TCM is often the most direct path to a solution.
- ✔ Harsh, slamming, or delayed gear shifts.
- ✔ The vehicle is stuck in a single gear (limp-home mode).
- ✔ Check Engine Light or Transmission Warning Light is illuminated.
- ✔ Diagnostic Trouble Codes (DTCs) like P0700, P0750, or other solenoid-related faults are present.
- ✔ A sudden drop in fuel efficiency.
- ✔ The transmission feels like it’s slipping between gears.
A Straightforward Guide to Your TCM Installation
One of the best features of this module is that it’s a DIY-friendly repair. Because we program it to your vehicle’s VIN before shipping, you can skip the expensive programming fees at the dealership. For a 2006-2009 Buick LaCrosse, the TCM is located under the lower air cleaner housing, making it accessible with basic hand tools.
- Safety First: Always disconnect the negative terminal from your car’s battery to prevent any electrical shorts and to help reset the vehicle’s computer systems.
- Locate the Module: Find the air cleaner box in your engine bay. You will need to remove the housing to access the TCM mounted below it.
- Disconnect and Remove: Carefully unplug the electrical connectors from the old TCM. Press the release tabs firmly to avoid breaking them. Then, unbolt the module from its mounting bracket.
- Install the New TCM: Bolt the new, pre-programmed module into place. Securely plug in the electrical connectors—you should hear a click as they lock in.
- Final Steps: Reinstall the air cleaner housing and reconnect the battery terminal. While the module is plug-and-play, it’s good practice to use a basic OBD-II scan tool to clear any stored fault codes from the system. Start the vehicle and enjoy your smooth-shifting transmission!
Guaranteed Fitment for Your GM Vehicle
This T42 Transmission Control Module is a direct-fit replacement for your 2006-2009 LaCrosse TCM and is also compatible with a wide range of other GM vehicles that use the 4L60E, 4L65E, and similar 4-speed automatic transmissions. Please verify your vehicle in the list below.
This part fits:
LACROSSE 06-09 Transmission; (lower air cleaner housing)
…and many other GM models including the Chevrolet Impala, GMC Sierra, Pontiac G6, and more. This module interchanges with part numbers 24252114, 24234503, 24230461, and others.
Frequently Asked Questions
Why is VIN programming so important?
VIN programming loads your vehicle’s specific software and calibrations onto the module. This ensures it communicates perfectly with your engine computer and transmission, providing optimal shift points, torque converter lockup, and fuel efficiency right out of the box, eliminating the need for a dealership visit.
Is this a difficult part to install myself?
Not at all. For most DIYers with basic tools, this is a job that can be completed in under an hour. The location on the LaCrosse (under the air filter box) is straightforward to access. Our pre-programming makes the electronic side of the job completely plug-and-play.
Will this fix a P0700 trouble code?
In many cases, yes. The P0700 code is a general fault code indicating the TCM has detected a problem. If the TCM itself is the source of the electrical fault, replacing it will resolve the code and the underlying issue causing it.
Do I need to send my old part back?
No, there is no core charge for this part. You can keep your old module or dispose of it responsibly without any hassle.
What kind of warranty comes with this part?
This module is backed by our comprehensive one-year warranty, giving you peace of mind and confidence in your repair.