If you’re dealing with the headaches of a faulty transmission in your 2007-2009 GMC Yukon, you’re not alone. As a technician with over two decades of experience, I’ve seen countless GM trucks and SUVs come into the shop with jerky shifting, a lit-up check engine light, and a driver at their wit’s end. The culprit is often a failing T42 Transmission Control Module (TCM), the electronic brain that orchestrates every gear change. A bad TCM can make your reliable Yukon feel unpredictable and unsafe.
This isn’t just a replacement part; it’s a complete solution. We pre-program this OEM-quality T42 TCM, part number 24243901, directly to your vehicle’s VIN. This critical step ensures it communicates flawlessly with your engine computer and other systems right out of the box. You get to skip the expensive and time-consuming trip to the dealership for programming. This is the definitive fix for restoring the smooth, reliable performance your vehicle had when it was new.
A Technician’s Notebook
A customer brought in a 2008 Yukon XL with classic symptoms: harsh 1-2 shifts and occasional slipping out of gear. The codes pointed to a shift solenoid (P0750 range), a common assumption. However, after 20 years of diagnostics, I know to check the source. We tested the solenoid’s resistance and wiring, and they were fine. The real issue was the TCM itself; its internal drivers were failing intermittently, sending erratic signals. Replacing just the solenoid would have been a waste of time and money. By installing a properly programmed 2007-2009 Yukon TCM, we resolved the root cause and prevented a costly comeback.
Is Your Yukon Exhibiting These Telltale Signs?
- ✔ Harsh, slamming, or erratic gear shifts that make driving uncomfortable.
- ✔ The vehicle is stuck in a single gear (often called “limp mode”) and won’t shift up or down.
- ✔ Your dashboard is lit up with a Check Engine Light or Transmission Warning Light.
- ✔ Diagnostic trouble codes (DTCs) like P0700 (Transmission Control System Malfunction), P0750-P0758 (Shift Solenoid errors), or other communication codes are present.
- ✔ Noticeable decrease in fuel economy as the transmission operates inefficiently.
- ✔ Delayed engagement when shifting from Park to Drive or Reverse.
A Straightforward 30-Minute Installation Guide
Replacing the TCM on your Yukon is a job most DIYers can handle with basic tools. For these GMT900 platform trucks and SUVs, the module is typically very accessible.
- Safety First: Always disconnect the negative terminal from your vehicle’s battery to prevent electrical shorts and help reset the vehicle’s computer systems.
- Locate the Module: On most 2007-2009 Yukon models, the TCM is located in the engine bay, mounted right next to the battery. It’s a silver box with several large electrical connectors.
- Disconnect and Remove: Carefully unclip the wiring harnesses. They have locking tabs, so don’t force them. Once disconnected, unbolt the module from its mounting bracket.
- Install the New TCM: Bolt the new, VIN-programmed module into place. Reconnect the wiring harnesses securely, ensuring each clip clicks into place.
- Final Steps: Reconnect the battery terminal. While our programming handles the critical setup, it’s good practice to use a basic OBD2 scan tool to clear any stored fault codes from the ECU. Start the vehicle and test drive to confirm smooth shifting.
Verified Compatibility for Your GM Vehicle
This T42 TCM is a direct-fit replacement for a wide range of General Motors vehicles equipped with 4-speed automatic transmissions like the 4L60E, 4L65E, and 4L70E. While this page focuses on the 2007-2009 Yukon TCM, it is also compatible with the following models. Please verify the location noted for your specific vehicle.
Interchangeable Part Numbers: 24252114, 24234503, 24230461, 24234274, 24235340, 24235754, 24238856, 24239224, 24239926, 24240400, 24241806, 24243901, 24243921, 24255280, 24256960, 24235732, 24235753, 24240449, YNXS
Frequently Asked Questions
What exactly does ‘VIN Programmed’ mean?
It means we load your vehicle’s unique 17-digit Vehicle Identification Number (VIN) and the latest GM software onto the module before shipping. This ensures the TCM works perfectly with your Yukon’s specific configuration (engine, axle ratio, tire size) for optimal shift points and performance, eliminating the need for dealership programming.
Do I need to send my old TCM back (core charge)?
No, there is absolutely no core charge or need to return your old part. This saves you the hassle and expense of shipping your old, faulty module back to us.
Will this fix a P0700 trouble code?
A P0700 code is a general fault code indicating the TCM has detected a problem. This module often resolves the underlying issue causing the P0700, especially if it’s accompanied by other specific solenoid or shifting codes. However, you should always confirm the issue isn’t with external wiring or the transmission’s internal mechanical parts.
Is this part covered by a warranty?
Yes, this transmission control module is backed by our one-year warranty, giving you confidence and peace of mind in your repair.
Can I install this myself if I’m not a mechanic?
Absolutely. For the GMC Yukon and similar trucks/SUVs, the TCM is typically located next to the battery and is held in by a few bolts. With basic hand tools, most people can complete the installation in under 30 minutes. Our plug-and-play programming makes it a straightforward swap.