If you’re dealing with the headaches of a faulty transmission in your 2006 GMC Envoy XL, you’ve come to the right place. As a technician with over two decades of experience under the hood, I’ve seen countless drivers frustrated by erratic shifting, check engine lights, and the dreaded ‘limp mode.’ More often than not, the culprit is a failing Transmission Control Module (TCM). This T42 series TCM, part number 24243901, is the definitive, reliable solution to restore your vehicle’s performance and your peace of mind.
This isn’t just a replacement part; it’s a complete, ready-to-install fix. We pre-program each module to your vehicle’s specific VIN, loading the latest GM software updates. This critical step ensures seamless communication between the TCM, your engine, and the transmission, eliminating the need for an expensive trip to the dealership for programming. It’s designed to directly address the common failure points in the original modules, providing a stable and long-lasting repair for your automatic transmission (like the 4L60E, 4L65E, and 4L70E).
Diagnosing Your 2006 Envoy XL TCM Failure
A failing TCM can mimic other transmission problems, making diagnosis tricky. In my shop, the symptoms are almost always the same. The vehicle might suddenly start shifting harshly, bang into gear, or refuse to shift at all. These issues are often caused by internal circuit board failures within the original TCM, typically due to heat and vibration in the engine bay. Replacing it with our pre-programmed module is the most direct path to a permanent fix.
Case Study: A Tricky Diagnosis
I once had a 2006 Envoy XL in the bay with classic symptoms: intermittent harsh 1-2 shifts and a persistent P0700 code. The owner had already replaced two shift solenoids with no luck. The problem was intermittent, making it hard to pin down. After checking the wiring harness for integrity, I suspected the TCM. We installed one of our VIN-programmed T42 modules, and the difference was immediate. The shifts were crisp and smooth, and the codes never returned. The pre-programming was key—it saved the customer hundreds in dealership fees and got them back on the road the same day.
Is Your GM Vehicle Showing These Telltale Signs?
- ✔ Harsh, erratic, or delayed gear shifts that make driving uncomfortable.
- ✔ The vehicle is stuck in ‘limp mode,’ usually in 2nd or 3rd gear, with limited power.
- ✔ Check Engine Light or Transmission Warning Light is on with Diagnostic Trouble Codes (DTCs) like P0700, P0750, or other solenoid-related faults.
- ✔ A complete failure to upshift or downshift, leading to poor acceleration and terrible fuel economy.
- ✔ Unexplained stalling or intermittent loss of communication with the transmission.
A Straightforward Guide to Installation
- ✔ Safety First: Disconnect the negative terminal from your vehicle’s battery to prevent any electrical shorts and to help reset the onboard systems.
- ✔ Locate the Module: On most GM trucks and SUVs like the Envoy, the TCM is found in the engine compartment. Common locations include the LH (driver’s side) engine compartment, next to the battery, or under the air cleaner housing.
- ✔ Disconnect and Remove: Carefully unplug the electrical connectors. Use a small flathead screwdriver to gently release the locking tabs if necessary. Then, unbolt the module from its mounting bracket.
- ✔ Install the New Module: Bolt the new, pre-programmed TCM into place and securely reconnect the electrical harnesses. You should hear a ‘click’ as they lock in.
- ✔ Final Steps: Reconnect the battery terminal. While our VIN programming handles the critical setup, it’s always good practice to use a basic OBD2 scan tool to clear any stored fault codes from the vehicle’s memory. Start the vehicle and take it for a test drive to confirm smooth shifting.
Verified Vehicle Compatibility
This module is a direct replacement for a wide range of General Motors vehicles equipped with the T42 TCM. Please verify your model and year from the list below. It is interchangeable with numerous part numbers, including 24252114, 24234503, 24243901, and more, ensuring a perfect match for your repair needs.
Fits Models Including: GMC Envoy, Envoy XL, Sierra, Yukon, Savana; Chevrolet Tahoe, Silverado, Suburban, Impala, Cobalt, HHR; Buick LaCrosse, Lucerne; Cadillac DTS; Pontiac G6; Hummer H3, and many more from 2006-2014. Please confirm your specific application in our fitment chart.
Frequently Asked Questions
What does ‘VIN Programmed’ actually mean for me?
It means this module arrives ready for installation right out of the box. We load your vehicle’s specific VIN and the latest GM software onto the module before shipping. This ensures it works perfectly with your engine and transmission without requiring any additional, expensive programming from a dealer or mechanic.
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, saving you the time and hassle of a return shipment.
Will this fix a P0700 trouble code?
A P0700 code is a general fault request from the TCM to the main engine computer (ECM) to turn on the check engine light. While this module often resolves the underlying issue causing the P0700 (like a bad solenoid circuit), you should always diagnose any other specific codes (e.g., P0753) that are present. In many cases, a faulty TCM is the root cause.
Is any special relearn procedure needed after installation?
No special relearn procedure is required. After installing the module and clearing any old codes with a scan tool, the transmission will adapt to the new module’s precise shift commands as you drive.