If the transmission in your 2006-2007 Chevrolet Monte Carlo is acting up—with jarring shifts, delayed gear engagement, or a frustrating check engine light—the culprit is often a failing Transmission Control Module (TCM). As a technician with over two decades of experience, I’ve seen how a faulty TCM can make an otherwise great car feel unreliable. The TCM is the electronic brain of your automatic transmission, and when it fails, it can cause a host of problems that seem complex but have a straightforward solution.
This OEM-quality T42 Transmission Control Module, part number 24243921, is the definitive fix for these issues. We take the guesswork and high dealership costs out of the equation. Before we ship it, we program the module to your car’s specific Vehicle Identification Number (VIN). This ensures it communicates perfectly with your vehicle’s systems right out of the box, restoring the smooth, predictable shifting performance you expect from your Monte Carlo. No expensive trips to the dealer for programming are necessary.
A Technician’s Notebook
I remember a 2007 Monte Carlo that came into my bay with a classic case of what the owner called ‘transmission confusion.’ It would hesitate to shift out of first gear when cold, then slam into second. On the highway, it would occasionally drop out of overdrive for no reason. The owner had already replaced a shift solenoid with no improvement. A quick scan showed a P0700 (Transmission Control System Malfunction) and an intermittent solenoid circuit code. Instead of chasing ghosts, we checked the TCM. Sure enough, it was the source of the erratic signals. Installing a pre-programmed 2006-2007 Monte Carlo TCM like this one solved every single issue in under 30 minutes. It’s a common failure point, and this part is the reliable, direct-fit solution.
Is Your Monte Carlo Showing These Telltale Signs?
A failing TCM doesn’t always mean a complete transmission failure. Catching it early can save you from further damage. Look out for these common indicators:
- ✔ Unpredictable or harsh shifting between gears.
- ✔ The vehicle gets stuck in one gear, often called “limp mode.”
- ✔ Check Engine Light or Transmission Warning Light is illuminated on the dash.
- ✔ Diagnostic Trouble Codes (DTCs) like P0700, P0750, or other solenoid-related codes are present.
- ✔ A noticeable decrease in fuel economy due to inefficient shifting.
- ✔ Delayed engagement when shifting from Park to Drive or Reverse.
A Straightforward Guide to Installation
This is a job most DIY enthusiasts can handle with basic tools. For the 2006-2007 Monte Carlo, the TCM is typically located under the lower air cleaner housing, making it accessible in your own garage.
- 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 TCM, which is situated beneath the air cleaner box in your Monte Carlo’s engine bay.
- 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 place and securely fasten it. Reconnect the electrical harnesses, ensuring they click into place.
- Final Steps: Reconnect the 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 system. Start the car and enjoy restored performance.
Verified Vehicle Compatibility List
This T42 TCM is a direct replacement for part number 24243921 and other interchangeable numbers. While this listing is focused on the 2006-2007 Monte Carlo TCM, it also fits a wide range of other GM vehicles. Please confirm your model and location below:
- CHEVROLET MONTE CARLO (2006-2007): Transmission; (lower air cleaner housing)
- CHEVROLET IMPALA (2006-2011): Transmission; (lower air cleaner housing)
- BUICK LACROSSE / ALLURE (2006-2009): Transmission; (lower air cleaner housing)
- PONTIAC GRAND PRIX (2006-2008): Transmission; (lower air cleaner housing)
- And many more GM models… (Please see the full fitment list for other compatible vehicles like the Silverado, Tahoe, Yukon, HHR, and Cobalt.)
Frequently Asked Questions
Do I need to have this TCM programmed by a dealer?
No. This module comes fully pre-programmed to your vehicle’s VIN. It is a plug-and-play solution that requires no additional programming or dealership visits, saving you time and money.
What is the main benefit of VIN programming?
VIN programming loads the latest GM software specific to your Monte Carlo. This ensures optimal shift points, torque converter lockup, and fuel efficiency, correcting the root cause of many common transmission DTCs.
Is this part difficult to install on my 2006 Monte Carlo?
Not at all. For a Monte Carlo, the TCM is located under the air cleaner housing. The replacement is a simple unbolt-and-unplug process that typically takes less than 30 minutes with basic hand tools.
Will this fix a P0700 trouble code?
A P0700 code is a general transmission fault request. Often, it is triggered by a failing TCM. Replacing a faulty TCM with this pre-programmed unit is a very common and effective way to resolve a P0700 code and related specific codes (like for solenoids).
Is there a core charge for my old part?
No, there is no core charge. You can keep your old module without the hassle of returning it, making the repair process simpler and more convenient.