End Your Buick’s Shifting Nightmares for Good
Is your 2006-2009 Buick LaCrosse suffering from jarring shifts, getting stuck in gear, or flashing a transmission warning light? You’re not just dealing with an annoyance; you’re facing a classic case of a failing Transmission Control Module (TCM). As the electronic brain of your automatic transmission, a faulty TCM can cripple your car’s performance and reliability. This OEM-quality T42 TCM, part number 24235754, is the definitive solution, arriving pre-programmed to your vehicle’s VIN for a hassle-free, plug-and-play installation that restores the smooth, predictable performance you expect from your Buick.
A Technician’s Notebook: The Misleading Solenoid Code
I remember a 2008 LaCrosse that came into my bay with a P0752 code (Shift Solenoid ‘A’ Stuck On). The owner had already replaced the solenoid twice at another shop, but the harsh 1-2 shift and intermittent ‘limp mode’ persisted. After a quick data stream check, I saw the TCM was commanding the shift, but the feedback was erratic. This is a tell-tale sign I’ve seen hundreds of times. The root cause wasn’t the mechanical solenoid; it was the failing driver circuit inside the original TCM. We installed a VIN-programmed module, cleared the codes, and the car shifted perfectly. It’s a crucial reminder: diagnostic trouble codes often point to the symptom, not the source. A failing TCM is frequently the real culprit behind persistent solenoid codes.
Is Your Buick LaCrosse Showing These Telltale Signs?
A failing TCM doesn’t just get worse; it can leave you stranded. If you’re experiencing any of these common symptoms, it’s time to address the problem. This module is designed to resolve these issues directly.
- âś” Harsh, erratic, or delayed gear shifts that make driving uncomfortable.
- âś” The vehicle is stuck in a single gear (often called “limp mode”) to protect the transmission.
- âś” Check Engine Light or Transmission Warning Light is illuminated on your dashboard.
- âś” Your mechanic finds Diagnostic Trouble Codes (DTCs) like P0700, P0750, P0751, or other solenoid-related faults.
- âś” A noticeable decrease in fuel economy as the transmission operates inefficiently.
- âś” Complete failure to shift, or the transmission seems to slip between gears.
A Straightforward Guide to Your LaCrosse TCM Installation
One of the best features of this module is its simple installation. You don’t need specialized tools or a trip to the dealership. For your 2006-2009 LaCrosse, the TCM is conveniently located under the lower air cleaner housing, making it accessible for a quick swap.
- Safety First: Always disconnect the negative terminal from your vehicle’s battery before starting any electronic component replacement.
- Locate the Module: On your LaCrosse, you’ll find the TCM situated beneath the air cleaner box. You will need to remove the air cleaner assembly to gain access.
- Disconnect and Remove: Carefully unclip the wiring harness connectors from the old TCM. Then, unbolt the module from its mounting bracket.
- Install the New Module: Bolt the new, pre-programmed TCM into place and securely reconnect the wiring harnesses. You should hear a ‘click’ as they lock in.
- Final Steps: Reinstall the air cleaner assembly and reconnect the battery terminal. Start the vehicle and allow it to run for a moment. Use a basic OBD2 scanner to clear any stored fault codes to complete the process.
Verified Vehicle Compatibility
This T42 Transmission Control Module is a direct-fit replacement for a wide range of General Motors vehicles. While this page focuses on the 2006-2009 LaCrosse Transmission Control Module, it is also compatible with the following models. Please verify your vehicle’s specific location, as it can vary.
- Buick LaCrosse / Allure (06-09): Found in the lower air cleaner housing.
- Buick Lucerne (06-11): Located in the LH engine compartment.
- Chevrolet Cobalt / Impala / HHR / Monte Carlo (06-11): Various locations including LH strut tower or lower air cleaner housing.
- Chevrolet Silverado / Tahoe / Suburban (07-13): Typically located next to the battery.
- GMC Sierra / Yukon / Savana (07-14): Typically located next to the battery or on the RH engine compartment.
- Pontiac G6 / Grand Prix (06-10): Found at the LH strut tower or lower air cleaner housing.
- …and many other GM models listed in the original fitment chart. This part is interchangeable with service numbers 24252114, 24234503, 24235754, and more.
Frequently Asked Questions
What does ‘VIN Programmed’ actually mean for me?
It means we flash the module with your car’s specific Vehicle Identification Number (VIN) and the latest GM software before we ship it. This ensures it communicates perfectly with your car’s engine computer and other systems right out of the box, eliminating the need for an expensive programming service at a dealership.
Will this fix a P0700 trouble code?
Yes, very often. A P0700 is a generic code indicating the TCM has detected a fault. By replacing the failing TCM, you are addressing the source of the fault, which in turn should clear the P0700 and any related specific codes (like for solenoids) after installation.
Is this a difficult part for a DIYer to install?
Not at all. For the Buick LaCrosse, the location under the air cleaner is straightforward to access with basic hand tools. The entire process typically takes less than an hour, making it a very manageable weekend project for most DIY enthusiasts.
Do I need to send my old TCM back?
No, there is no core charge for this part. You can keep your old module or dispose of it responsibly without any extra hassle or fees.
What kind of warranty is included?
This transmission control module is backed by our one-year, hassle-free warranty, giving you confidence and peace of mind in your repair.