Restore Peak Performance to Your GMC Envoy’s Transmission
Are you experiencing frustrating and unpredictable shifting in your 2006-2009 GMC Envoy? Issues like harsh gear changes, getting stuck in limp mode, or seeing the dreaded check engine light can point directly to a failing Transmission Control Module (TCM). The TCM is the electronic brain of your automatic transmission, responsible for orchestrating every shift with precision. When it fails, drivability suffers. This genuine OEM-quality T42 Transmission Control Module, service part number 24238856, is the definitive solution to restore your vehicle’s smooth operation and reliability.
From the Diagnostic Bay
We had a 2008 Chevy Trailblazer (which uses the same platform as the Envoy) come in with a persistent P0752 code (Shift Solenoid A Stuck On). The owner had already replaced the solenoid twice at another shop with no luck. The problem wasn’t the solenoid itself, but the TCM which was sending a faulty signal, keeping the solenoid energized. After a quick scan confirmed our suspicion, we installed one of our VIN-programmed T42 modules. The code cleared immediately, and the transmission shifted perfectly on the test drive. It’s a classic case where chasing codes without understanding the system leads to wasted time and money; often, the root cause is the controller, not the component.
Is Your Vehicle Showing These Telltale Signs of TCM Failure?
- ✔️ Harsh, erratic, or delayed gear shifting that makes driving uncomfortable.
- ✔️ The vehicle is stuck in a single gear (often called “limp mode”) to protect the transmission.
- ✔️ Check Engine Light or Transmission Warning Light is illuminated on your dashboard.
- ✔️ Diagnostic Trouble Codes (DTCs) such as P0700, P0750, P0755, or other solenoid-related codes are present.
- ✔️ A noticeable decrease in fuel economy due to inefficient shifting.
- ✔️ Complete failure to shift gears, leaving you stranded.
The Definitive Solution: A Programmed 2006-2009 Envoy Transmission Module
Don’t settle for a generic, unprogrammed module that requires an expensive trip to the dealership. Our T42 TCMs are meticulously programmed to your vehicle’s specific Vehicle Identification Number (VIN) before they ship. This critical step ensures that the module communicates flawlessly with your Envoy’s engine computer and other systems right out of the box. It arrives loaded with the latest GM software updates, resolving common factory bugs and optimizing transmission performance for longevity. This is a true plug-and-play solution designed for both professional technicians and savvy DIYers.
This module is a direct replacement for a wide range of GM part numbers, including 24252114, 24234503, 24230461, and 24238856. It’s engineered to meet and exceed original equipment specifications, providing dependable control over your 4L60E, 4L65E, or 4L70E transmission. Installation is straightforward, typically located in the engine compartment on the driver’s side. With no core charge, you can complete the repair without the hassle of returning your old part.
Frequently Asked Questions
Why is VIN programming so important for this part?
VIN programming loads your vehicle’s specific calibration files onto the module. This ensures it knows the correct gear ratios, tire size, and electronic protocols for your exact Envoy. Without it, the module won’t function correctly, leading to persistent shifting problems and error codes.
Will this fix a P0700 trouble code?
A P0700 code is a general fault code, indicating that the TCM has detected a problem and has requested the check engine light to be turned on. While this module often resolves the underlying issue causing the P0700 (like a solenoid circuit fault), you should always diagnose the specific codes stored within the TCM to confirm the root cause.
Is this part difficult to install myself?
For someone with basic mechanical skills, the installation is quite manageable. It’s typically located in the engine bay and held in by a few bolts with electrical connectors. The most important steps are disconnecting the battery beforehand and ensuring the connectors are seated properly. The entire process often takes less than 30 minutes.
What transmissions is this T42 module compatible with?
This T42 TCM is designed for popular GM 4-speed automatic transmissions, including the 4L60E, 4L65E, 4L70E, and 4L80E. It fits a vast range of vehicles from 2006-2014, not just the Envoy. Please check the fitment list to confirm for other models.
Do I need to send my old module back?
No, there is no core charge for this part. You can keep your old module, recycle it, or dispose of it as you see fit, making for a simpler, faster transaction.