Restore Flawless Shifting to Your GMC Envoy
If your 2006-2009 GMC Envoy is suffering from harsh shifting, getting stuck in gear, or throwing transmission-related codes, the culprit is often a failing Transmission Control Module (TCM). As an expert with over two decades of hands-on diagnostic experience, I’ve seen how a faulty TCM can sideline an otherwise reliable SUV. This replacement T42 TCM, part number 24234274, is the definitive solution to restore your vehicle’s transmission performance and drivability without a costly trip to the dealership.
The TCM is the brain of your automatic transmission, responsible for processing sensor data to execute smooth, precise gear changes. When it fails, communication breaks down, leading to the frustrating and potentially damaging symptoms you’re experiencing. Our module comes pre-programmed to your vehicle’s specific VIN, ensuring it works perfectly right out of the box. This eliminates the need for expensive programming tools or dealer intervention, making it an ideal fix for both professional mechanics and savvy DIYers.
Case Study: A Tricky Diagnosis
I recall an ’07 Envoy that came into my shop with classic limp-mode symptoms—stuck in 3rd gear with a P0700 code. The owner had already replaced a shift solenoid based on a generic code reader’s suggestion, but the problem persisted. My professional scan tool showed erratic voltage readings from the TCM. After swapping in a VIN-programmed module like this one, all communication was restored, the codes cleared, and the transmission shifted like new. It’s a prime example of why addressing the root cause—the TCM—is crucial for a lasting repair.
Diagnosing a Faulty 2006-2009 Envoy TCM
A failing TCM can mimic other transmission problems, but there are specific indicators to watch for. If your Envoy exhibits a combination of these issues, it’s highly likely the module is at fault. This component is designed to resolve these exact problems, getting you back on the road with confidence. Don’t let a small electronic part lead to a major transmission headache.
Common Signs of a Failing T42 Module
- âś” Erratic, harsh, or delayed gear shifts that disrupt smooth driving.
- âś” The vehicle enters “limp mode,” often getting stuck in a single gear (usually 2nd or 3rd).
- âś” Check Engine Light or Transmission Warning Light is illuminated on the dash.
- âś” Diagnostic Trouble Codes (DTCs) are present, such as P0700, P0750, or other solenoid-specific faults.
- âś” A complete loss of upshifting or downshifting capability.
- âś” Noticeably poor fuel economy due to inefficient gear management.
- âś” Intermittent or total loss of communication with the TCM when checked with a scan tool.
A Straightforward Guide to Installation
One of the best features of this module is its simple, plug-and-play installation. For a 2006-2009 Envoy, the TCM is conveniently located in the engine bay, making access easy. You can complete this job in under 30 minutes with basic hand tools.
- Safety First: Always disconnect the negative terminal from your vehicle’s battery before starting any electrical work.
- Locate the Module: On the Envoy, the TCM is typically found in the left-hand (driver’s side) of the engine compartment.
- 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 TCM: Mount the new, VIN-programmed TCM onto the bracket and securely fasten the bolts. Reconnect the electrical harnesses, ensuring they click into place.
- Final Steps: Reconnect the negative battery terminal. While the module is plug-and-play, it’s good practice to use a scan tool to clear any stored fault codes from the vehicle’s memory. Start the engine and test drive to confirm smooth shifting.
Verified Vehicle Compatibility
This T42 Transmission Control Module is a direct replacement for part number 24234274 and is interchangeable with many other GM service numbers. It fits a wide range of vehicles equipped with 4-speed automatic transmissions like the 4L60E, 4L65E, and 4L70E. While this page focuses on the 2006-2009 Envoy TCM, please see the comprehensive list below to verify fitment for other models.
Partial Fitment List:
- GMC Envoy: 2006-2009
- Chevrolet Silverado & GMC Sierra: 2007-2013
- Chevrolet Tahoe & GMC Yukon: 2007-2009
- Chevrolet Impala: 2006-2011
- Chevrolet Trailblazer: 2006-2009
- Hummer H3: 2008-2010
- Cadillac DTS: 2006-2011
- Buick LaCrosse: 2006-2009
- …and many more GM models. Please check the full list for your specific vehicle and options.
Frequently Asked Questions
What does ‘VIN Programmed’ mean for me?
It means we load your vehicle’s unique Vehicle Identification Number (VIN) and the latest GM software onto the module before shipping. This ensures it communicates perfectly with your vehicle’s other computers, requiring no extra programming or dealer visits. It’s ready to install right out of the box.
Will this fix my transmission’s limp mode?
Yes, in most cases. Limp mode is a common symptom of a failed TCM. By replacing the faulty module with this pre-programmed unit, you restore proper communication and function, which resolves limp mode and related error codes.
Do I need to send my old part back (core charge)?
No, there is absolutely no core charge or need to return your old module. You can keep it or dispose of it at your convenience, making the process faster and hassle-free.
Is this a genuine OEM part?
This is an OEM-quality part built to the same standards and specifications as the original factory module. It is guaranteed to provide reliable performance and is backed by our one-year warranty.
Can I install this myself if I’m not a mechanic?
Absolutely. The installation process is very straightforward and typically takes less than 30 minutes with basic tools. Our step-by-step guide is designed to help DIYers complete the job with confidence.