Is Your GMC Envoy Shifting Erratically?
If you’re dealing with unpredictable gear changes, a check engine light that won’t go away, or your 2006-2009 GMC Envoy is stuck in ‘limp mode,’ a failing Transmission Control Module (TCM) is the most likely culprit. The TCM is the electronic brain of your automatic transmission, responsible for orchestrating every shift with precision. When it fails, it can cause a cascade of frustrating and potentially damaging issues, turning your reliable SUV into a source of constant worry. This genuine quality T42 TCM, service part number 24234503, is the definitive solution to restore your vehicle’s performance and peace of mind.
From the Diagnostic Bay
We had a 2008 GMC Envoy come into the shop with classic symptoms: harsh 1-2 shifts and a P0700 trouble code. The owner had already spent a small fortune replacing shift solenoids at another shop, but the problem persisted. We knew from experience that on these 4L60E-equipped vehicles, the internal electronics of the TCM are a common failure point. After confirming power and ground, we installed one of our VIN-programmed T42 modules. The installation took less than 30 minutes. After a quick battery disconnect to clear the adaptive memory and a test drive, the Envoy shifted like it just rolled off the factory floor. The customer was thrilled to have a simple, permanent fix without another expensive trip to the dealership.
Identifying a Faulty Envoy Transmission Control Module
The TCM communicates with the Engine Control Module (ECM) and various sensors to determine the perfect moment to shift gears, engage the torque converter clutch, and adjust line pressure. Over time, heat cycles and vibrations can degrade the delicate internal circuits, leading to a host of noticeable problems. Recognizing these signs early can save you from more extensive transmission damage down the road. This replacement Envoy Transmission Control Module is engineered to resolve these issues directly.
Common Symptoms of a Failing T42 TCM
- ✔ Harsh, delayed, or erratic shifting between gears.
- ✔ Vehicle getting stuck in a single gear (limp mode), often 2nd or 3rd.
- ✔ Illuminated Check Engine Light or Transmission Warning Light on the dash.
- ✔ Diagnostic Trouble Codes (DTCs) such as P0700, P0750, or other solenoid-specific codes.
- ✔ Failure to upshift or downshift, resulting in poor acceleration and performance.
- ✔ A noticeable decrease in fuel economy due to inefficient gear management.
- ✔ Intermittent loss of communication with the scan tool or other modules.
The Plug-and-Play Advantage: VIN Programming Included
Replacing a TCM isn’t just about swapping hardware. Modern vehicles require the module to be programmed specifically to the vehicle’s Vehicle Identification Number (VIN). Without this critical step, the module won’t communicate correctly with the rest of your Envoy’s systems. Our service eliminates this costly and inconvenient step. We pre-program this Envoy Transmission Control Module with your vehicle’s VIN and the latest GM software updates before it ships. This ensures a true plug-and-play installation—no expensive dealership visits or specialized tools required. Simply install the module, reconnect your battery, and you’re ready to drive.
Key Features & Benefits:
- VIN-Programmed for Your Vehicle: Arrives ready for immediate installation, ensuring perfect compatibility and optimal transmission performance from the moment you plug it in.
- Restores Smooth Operation: Directly addresses common shifting problems, limp mode, and transmission-related error codes.
- OEM-Standard Quality: Built to meet or exceed original equipment specifications for long-lasting reliability and durability.
- Broad Compatibility: An exact replacement for service numbers 24234503, 24242391, 24252114, and many others, covering a wide range of GM vehicles including the Chevrolet Silverado, Tahoe, GMC Sierra, Buick LaCrosse, and more.
- No Core Charge: Keep your old part without the hassle or expense of returning a core.
Frequently Asked Questions
What does ‘VIN-programmed’ actually mean?
It means we flash the module with your specific vehicle’s factory software using your 17-digit VIN. This allows the TCM to communicate perfectly with your Envoy’s engine computer and other systems, just like the original part did. It’s a critical step that makes the installation seamless.
Will this part fix my P0700 transmission code?
A P0700 code is a general fault code indicating the TCM has detected a problem. While this module often resolves the root cause that triggers a P0700, it’s essential to have the vehicle scanned for more specific codes (like P0751, P0756, etc.) to confirm the diagnosis. In most cases of electronic failure, this module is the correct fix.
How difficult is this to install on my 2007 Envoy?
Installation is straightforward for a DIY mechanic. On the GMC Envoy, the TCM is typically located in the engine compartment on the driver’s side (LH). The process involves disconnecting the battery, unplugging the electrical connectors, unbolting the old module, and installing the new one. The entire job usually takes less than 30 minutes.
Do I need to send my old part back?
No. We do not require a core return for this part. You can dispose of or keep your old module without any additional charges or hassle.
Is this compatible with transmissions other than the 4L60E?
Yes, this T42 TCM is compatible with a range of GM 4-speed automatic transmissions, including the 4L60E, 4L65E, 4L70E, and 4L80E found in a vast number of GM cars, trucks, and SUVs from 2006-2014. Please check the fitment list to confirm for your specific vehicle.