Restore Flawless Shifting to Your GMC Envoy
If your 2006-2009 GMC Envoy is suffering from erratic shifting, getting stuck in gear, or throwing transmission codes, the culprit is very likely a failing Transmission Control Module (TCM). As a technician with over two decades of experience, I’ve seen countless GM vehicles, from hardworking Sierra trucks to family-hauling Envoys, sidelined by this exact issue. The T42 TCM is the electronic brain of your automatic transmission, and when it fails, it can cause a cascade of problems that feel like a major mechanical failure. Don’t let a faulty module convince you that your transmission is shot. This VIN-programmed T42 TCM, part number 24235732, is the direct, reliable solution you need to get your vehicle back on the road, shifting as smoothly as it did from the factory.
A Technician’s Notebook: The Misdiagnosed Trailblazer
A customer brought in a 2007 Trailblazer—a vehicle that shares its platform and TCM with the Envoy—with a classic complaint: it was stuck in 3rd gear (limp mode) and the check engine light was on. He’d been to another shop that quoted him over $2,500 for a transmission rebuild. I pulled the codes and saw P0753 (Shift Solenoid ‘A’ Electrical). While this can point to a bad solenoid, my experience with these T42 modules told me to check the source first. The module’s internal drivers for the solenoids are a common failure point. Instead of a costly and unnecessary rebuild, we installed a VIN-programmed TCM. In less than an hour, the codes were gone, the vehicle was shifting through all gears perfectly, and the customer saved over two thousand dollars. This is why addressing the TCM first is critical for an accurate and cost-effective repair.
Is Your GMC Envoy Exhibiting These Transmission Problems?
A failing 2006-2009 Envoy TCM will often display clear warning signs. If you’re experiencing any of the following, it’s time to consider a replacement. Ignoring these symptoms can lead to more significant and expensive transmission damage down the line.
- ✔ Harsh, slamming shifts or delayed gear engagement.
- ✔ Vehicle is stuck in a single gear, often called “limp mode,” making it difficult to drive.
- ✔ Check Engine Light or Transmission Warning Light is illuminated on the dash.
- ✔ Diagnostic Trouble Codes (DTCs) are present, such as P0700 (Transmission Control System Malfunction), P0750-P0758 (Solenoid codes), or U-series communication codes.
- ✔ Failure to upshift or downshift properly, leading to poor acceleration and engine performance.
- ✔ A noticeable drop in fuel economy as the transmission operates inefficiently.
Get Your Envoy Shifting Smoothly in Under an Hour
One of the best features of this module is its straightforward installation. You don’t need to be a master mechanic to get this job done. For the 2006-2009 Envoy TCM, the process is simple and requires only basic hand tools.
- Safety First: Always disconnect the negative terminal from your vehicle’s battery before starting any electronic component replacement. This prevents electrical shorts and helps reset the vehicle’s systems.
- Locate the Module: On the GMC Envoy and similar platforms like the Trailblazer, the TCM is typically found in the engine compartment on the driver’s side (LH side), often mounted near the firewall or inner fender.
- Disconnect and Remove: Carefully unplug the electrical connectors from the old TCM. Press the release tabs firmly to avoid damaging the clips. Then, unbolt the module from its mounting bracket.
- Install the New Module: Bolt the new, VIN-programmed TCM into place. Reconnect the electrical harnesses, ensuring they click securely into position.
- Final Steps: Reconnect the battery terminal. Start the vehicle and allow it to idle for a few minutes. While the module is pre-programmed, it’s good practice to use a basic OBD2 scan tool to clear any stored fault codes from the initial failure. Test drive the vehicle to confirm smooth shifting.
Verified Fitment for Your GM Vehicle
This T42 Transmission Control Module is a direct-fit replacement for a wide range of General Motors cars, trucks, and SUVs. While this page focuses on the 2006-2009 Envoy TCM, it is also compatible with the following models. Please verify the location noted for your specific vehicle.
This module is a direct replacement for part numbers: 24242391, 24234503, 24252114, 24230461, 24234274, 24235340, 24235754, 24238856, 24239224, 24239926, 24240400, 24241806, 24243901, 24243921, 24255280, 24256960, 24235732, 24235753, 24240449, YNXS.
Fitment includes: GMC ENVOY (06-09), Chevrolet TRAILBLAZER (06-09), Buick RAINIER (06-07), Saab 9-7X (06-09), Chevrolet SILVERADO, GMC SIERRA, Chevrolet TAHOE, GMC YUKON, Chevrolet AVALANCHE, Chevrolet SUBURBAN, Cadillac DTS, Buick LACROSSE, Buick LUCERNE, Chevrolet IMPALA, Chevrolet MONTE CARLO, Pontiac GRAND PRIX, and many more. Please use the vehicle selector tool to confirm exact fitment.
Why is VIN programming so important?
Why is VIN programming so important?
VIN programming loads your vehicle’s specific software and calibrations onto the TCM. This ensures it communicates correctly with the engine controller and other modules, providing correct shift points, torque converter lockup, and line pressure. Without it, the transmission will not function correctly, which is why our pre-programmed modules save you a trip to the dealership.
Do I need to send my old part back?
No, there is no core charge for this part. You can keep your old module, which saves you the time and hassle of packaging and shipping it back.
What if I install this and still have shifting problems?
While the TCM is the most common point of failure, shifting issues can also be caused by bad solenoids, low fluid, or internal mechanical wear. If a new TCM doesn’t solve the problem, we recommend having a professional mechanic perform a pressure test and inspect the valve body and solenoids.
Is this part covered by a warranty?
Yes, this Transmission Control Module comes with a one-year warranty, giving you peace of mind and confidence in your repair.