Restore Flawless Shifting to Your Buick Allure
If your 2006-2009 Buick Allure is suffering from harsh shifting, delayed gear engagement, or has suddenly gone into limp mode, the culprit is often a failing Transmission Control Module (TCM). As the electronic brain of your automatic transmission, the T42 TCM orchestrates every gear change, manages torque converter lockup, and monitors system health. When it fails, it can cause a cascade of frustrating and potentially damaging issues. Over my 20+ years in automotive diagnostics, I’ve seen hundreds of these GM vehicles where a faulty TCM was the root cause of what seemed like a major mechanical failure. This replacement 2006-2009 Allure TCM is the definitive solution to restore your vehicle’s performance and peace of mind.
This isn’t a generic, one-size-fits-all module. We pre-program it to your vehicle’s specific VIN before it ships, ensuring it communicates perfectly with your car’s other systems right out of the box. This eliminates the need for an expensive trip to the dealership for programming, making it a perfect fix for both professional mechanics and savvy DIYers. By replacing your old module, you’re not just fixing a problem; you’re investing in the long-term health and reliability of your transmission.
From the Diagnostic Bay
I remember a 2008 Allure that came into the shop with a classic complaint: “It bangs into gear and the check engine light is on.” The owner had already replaced a shift solenoid based on a generic code, but the problem persisted. A quick scan with a proper tool showed a P0700 (Transmission Control System Malfunction) and intermittent communication loss with the TCM. Instead of chasing ghosts in the wiring harness, we went straight for the module. Once we installed a VIN-programmed TCM like this one, the harsh shifts vanished, the codes cleared, and the car drove like new. It’s a textbook example of how a single electronic part can mimic a severe mechanical issue, and why a quality, programmed module is the right fix.
Common Signs of a Failing T42 TCM
- ✔ Abrupt, harsh, or erratic gear shifts.
- ✔ The vehicle gets stuck in one gear (often 2nd or 3rd, known as “limp mode”).
- ✔ Check Engine Light or Transmission Warning Light is illuminated.
- ✔ Diagnostic Trouble Codes (DTCs) are present, especially P0700, P0750-P0758, or other solenoid-related faults.
- ✔ Delayed engagement when shifting from Park to Drive or Reverse.
- ✔ Poor fuel economy and a feeling of sluggish performance.
- ✔ Complete loss of communication with the TCM, preventing diagnostics.
DIY Installation: A Straightforward Fix
- ✔ Safety First: Before you begin, disconnect the negative terminal from your vehicle’s battery to prevent any electrical shorts and to help reset the system.
- ✔ Locate the Module: On the Buick Allure, the TCM is typically found bolted to the lower air cleaner housing in the engine bay. It’s a silver box with electrical connectors.
- ✔ Disconnect and Remove: Carefully unplug the electrical connectors. Press the release tabs firmly. Then, unbolt the module from its mounting bracket.
- ✔ Install the New Module: Bolt the new, pre-programmed TCM into place. Securely reconnect the electrical connectors, ensuring they click into place.
- ✔ Final Steps: Reconnect the battery terminal. Start the vehicle and let it idle for a few minutes. While the module is plug-and-play, it’s always best practice to use a basic OBD2 scan tool to clear any stored fault codes from the ECU.
Will This Fit My Vehicle?
This T42 Transmission Control Module, part number 24240449, is a direct-fit replacement for the specified models. It is also interchangeable with a wide range of other GM service numbers. While programmed specifically for the 2006-2009 Buick Allure, it is also compatible with the following vehicles:
- ALLURE 06-09 Transmission; (lower air cleaner housing)
- AVALANCHE 1500 07-08 Transmission; (next to battery)
- CANYON / COLORADO 08-12 Transmission; (RH rear engine compartment)
- COBALT / G5 / PURSUIT 06-10 Transmission; (LH strut tower)
- DTS 06-11 Transmission; (RH front engine compartment)
- ENVOY / TRAILBLAZER 06-09 Transmission; (LH engine compartment)
- EXPRESS / SAVANA VANS 06-14 Transmission; (RH engine compartment)
- GRAND PRIX / IMPALA / LACROSSE / MONTE CARLO 06-11 Transmission; (lower air cleaner housing)
- HHR 06-11 Transmission; (LH engine compartment)
- HUMMER H3 08-10 Transmission; (RH rear engine compartment)
- ION 06-07 Transmission; (behind LH strut tower)
- LUCERNE 06-11 Transmission; (LH engine compartment)
- MALIBU / AURA / G6 06-10 Transmission; (LH frame rail)
- MONTANA / RENDEZVOUS / TERRAZA / UPLANDER 06-09 Transmission; (LH strut tower)
- SIERRA / SILVERADO 1500/2500 07-13 Transmission; (next to battery)
- TAHOE / YUKON / SUBURBAN 07-09 Transmission; (next to battery)
- VUE 07-10 Transmission; (LH front engine compartment)
Frequently Asked Questions
Do I need to have this module programmed by a dealer?
No. This module comes fully pre-programmed to your vehicle’s VIN. It is ready for installation right out of the box, saving you time and the high cost of dealership programming.
What is the warranty on this part?
This Transmission Control Module is backed by our comprehensive one-year warranty, giving you confidence in your repair.
Where is the TCM located on my 2007 Buick Allure?
For the 2006-2009 Buick Allure, the TCM is conveniently located in the engine compartment, attached to the lower air cleaner housing, making it easily accessible for replacement.
Will this fix a P0700 trouble code?
A P0700 code indicates a general fault in the transmission control system. While a failing TCM is a very common cause for this code, you should ensure other potential issues like low fluid or faulty wiring have been checked. In many cases, replacing the TCM will resolve the P0700 and related codes.
Is there a core charge for my old part?
No, there is no core charge. You can keep your old part or dispose of it at your convenience without the hassle of returning it.