If your 2006-2009 Buick LaCrosse is suffering from harsh shifting, getting stuck in gear, or has an illuminated check engine light, a failing Transmission Control Module (TCM) is the most likely culprit. As a technician with over two decades of experience, I’ve seen how a faulty TCM can make a reliable car feel unpredictable and unsafe. This T42 TCM, part number 24235753, is the definitive solution, arriving pre-programmed to your vehicle’s specific VIN for a true plug-and-play repair.
A Technician’s Notebook
I remember a 2008 LaCrosse that came into the shop with a classic complaint: intermittent ‘limp mode.’ The customer would be driving fine, and then suddenly the car would refuse to shift out of 3rd gear. They had already replaced a shift solenoid with no luck. A quick scan showed a P0700 (Transmission Control System Malfunction) and some generic communication codes. Experience pointed directly to the TCM. The internal circuits on these modules can degrade from heat and vibration, causing erratic signals. We installed a VIN-programmed module like this one, and the problem was solved in under an hour, saving the customer hundreds compared to a dealership visit.
Is Your LaCrosse Showing These Symptoms?
A failing TCM can manifest in several ways. If you’re noticing any of the following, it’s time to consider a replacement:
- ✔ Harsh, jerky, or delayed gear shifts.
- ✔ Vehicle is stuck in a single gear (often called “limp mode”).
- ✔ Check Engine Light or Transmission Warning Light is on.
- ✔ Diagnostic Trouble Codes (DTCs) like P0700, P0750, or other solenoid-related faults are present.
- ✔ A sudden drop in fuel economy.
- ✔ The transmission seems to slip between gears.
A Straightforward Guide to Your 2006-2009 LaCrosse TCM Installation
This is a job most DIYers can handle with basic tools. For the 2006-2009 LaCrosse, the TCM is conveniently located under the lower air cleaner housing, making access relatively simple.
- Safety First: Disconnect the negative terminal from your car’s battery to prevent any electrical shorts.
- Access the Module: Remove the air cleaner assembly to expose the TCM mounted below it.
- Disconnect and Remove: Carefully unclip the electrical connectors from the old module. Then, unbolt the module from its mounting bracket.
- Install the New TCM: Mount the new, pre-programmed module in place and securely fasten the bolts. Reconnect the electrical connectors, ensuring they click into place.
- Reassemble and Finalize: Reinstall the air cleaner housing. Reconnect the battery terminal. Start the vehicle and use a basic OBD2 scan tool to clear any stored fault codes.
Verified Vehicle Compatibility
This module, service number 24235753, is a direct replacement for your 2006-2009 Buick LaCrosse. It is also compatible with a wide range of other GM vehicles that use the T42 TCM, including:
- Buick: Allure, Lucerne, Rainier, Rendezvous
- Chevrolet: Cobalt, HHR, Impala, Malibu, Monte Carlo, SSR, Tahoe, Silverado, Express Van, Colorado
- GMC: Envoy, Sierra, Savana Van, Canyon
- Pontiac: G5, G6, Grand Prix, Pursuit
- Saturn: Aura, Ion, Vue
- Cadillac: DTS
- Hummer: H3
- Saab: 9-7X
Note: This part interchanges with 24252114, 24234503, 24230461, 24234274, 24235754, 24256960, and others.
Frequently Asked Questions
What does ‘VIN Programmed’ mean for me?
It means this module is ready for installation right out of the box. We load your car’s specific Vehicle Identification Number (VIN) and the latest GM software onto the module before shipping. This ensures perfect communication with your vehicle’s other computers and eliminates the need for a costly programming session at a dealership.
Will this fix my P0700 code?
A P0700 is a general code indicating the TCM has detected a fault. In many cases where the TCM itself has failed internally, replacing it with this pre-programmed unit will resolve the P0700 and any related specific codes (like for solenoids or sensors).
Do I need any special tools for this installation?
No special tools are required. Basic hand tools like a socket set and screwdrivers are all you’ll need to access and replace the module on your LaCrosse. A simple OBD2 scanner to clear codes after installation is recommended but not always necessary.
Is there a core charge for my old part?
No, there is absolutely no core charge. You can keep your old part or dispose of it without the hassle of sending it back to us.