Is your 2007 or 2008 GMC Yukon XL 1500 suffering from frustrating transmission problems? If you’re dealing with harsh shifting, delayed gear engagement, or a check engine light that points to transmission codes, a failing Transmission Control Module (TCM) is the most likely culprit. This vital electronic component is the brain of your automatic transmission, and when it fails, it can make your reliable SUV feel unpredictable and unsafe. Restore your vehicle’s performance and peace of mind with our pre-programmed T42 Transmission Control Module, a direct-fit solution for part number 24243901.
From the Diagnostic Bay
We recently had a 2008 Yukon XL come into the shop with classic symptoms: it would slam into gear from a stop and sometimes refuse to shift past 3rd gear, triggering a P0700 code. The owner had already spent a small fortune replacing shift solenoids inside the transmission pan, with no improvement. After a quick scan and data stream analysis, we identified erratic communication from the TCM. The internal logic board had failed. We installed one of our VIN-programmed T42 modules, cleared the codes, and the Yukon was shifting like it just rolled off the factory floor. This simple replacement saved the customer from a costly and unnecessary transmission rebuild.
Why Your 2007-2008 Yukon XL TCM Needs a Reliable Replacement
The T42 TCM is responsible for interpreting data from various sensors to control hydraulic pressure, shift timing, and torque converter lockup. Over time, heat cycles and vibrations can cause internal electronic components to fail, leading to a host of drivability issues. Our module is built to meet or exceed original equipment standards, ensuring long-lasting reliability. The most significant advantage is our VIN programming service. We flash the module with your vehicle’s specific Vehicle Identification Number and the latest GM software before it ships. This means no expensive trips to the dealership for programming—it’s a true plug-and-play installation right out of the box.
Common Symptoms of a Failing TCM
- ✔ Erratic and Harsh Shifting: Your Yukon may bang into gear, hesitate between shifts, or feel like it’s slipping.
- ✔ Stuck in Gear / Limp Mode: The transmission may default to a single gear (often 2nd or 3rd) to prevent further damage, severely limiting your speed.
- ✔ Warning Lights: The Check Engine Light or a specific transmission warning light will illuminate on your dashboard.
- ✔ Diagnostic Trouble Codes (DTCs): You’ll often see codes like P0700 (Transmission Control System Malfunction) or other solenoid-specific codes (P0751, P0756, etc.).
- ✔ Poor Fuel Economy: Inefficient shifting and torque converter operation can lead to a noticeable drop in MPG.
- ✔ No Communication: In severe cases, a scan tool may be unable to communicate with the TCM at all, indicating a complete failure.
A Simple Solution for a Complex Problem
Don’t let a faulty module sideline your vehicle. Replacing the TCM is a straightforward job that can be done with basic hand tools in under an hour. On the 2007-2008 Yukon XL 1500, the module is conveniently located in the engine compartment, typically next to the battery. Simply disconnect the battery, unplug the electrical connectors from the old module, unbolt it, and install the new one in its place. Once reconnected, your Yukon will have its shifting logic and performance fully restored.
Frequently Asked Questions
What does ‘VIN-programmed’ mean for my installation?
It means we load your vehicle’s specific VIN and the latest factory software onto the module before we ship it to you. This ensures it communicates perfectly with your engine computer and other systems without needing any additional, expensive programming from a dealership. It’s ready to install right out of the box.
Will this fix my P0700 and solenoid codes?
Yes, in most cases. A P0700 code is a general fault code indicating the TCM has detected a problem. Often, the problem is the TCM itself, which can also trigger false solenoid codes. Replacing a faulty TCM with our programmed unit will typically resolve these codes after they are cleared with a scan tool.
How do I know if the TCM is bad and not the transmission itself?
While a full diagnosis is always best, TCM failure often presents as intermittent electrical issues, multiple seemingly unrelated codes, or harsh shifting that isn’t accompanied by grinding noises or burnt fluid. If the transmission fluid is clean and full, and the problems are more electronic in nature, the TCM is the primary suspect.
Is this a difficult part to install myself?
For most DIY mechanics, this is a relatively easy installation. On your Yukon XL, the TCM is located next to the battery. The process involves disconnecting the battery, unplugging a few electrical connectors, and removing a few bolts. No special tools are required, and it typically takes less than 30 minutes.
Do I need to send my old module back for a core charge?
No, there is no core charge for this part. You can keep your old module or dispose of it at your convenience, making the purchasing process simpler and more affordable.