Restore Flawless Shifting to Your Chevrolet Trailblazer
If your 2006-2009 Chevrolet Trailblazer is suffering from erratic shifting, getting stuck in gear, or has an illuminated check engine light, a failing Transmission Control Module (TCM) is the most likely culprit. As the electronic brain of your automatic transmission, the TCM dictates every gear change and torque converter operation. When it fails, it can mimic a catastrophic transmission failure, leading to costly misdiagnoses. This OEM-quality T42 TCM, part number 24243901, is the definitive solution, arriving pre-programmed to your vehicle’s specific VIN for a true plug-and-play repair.
Is Your Trailblazer Exhibiting These Transmission Issues?
A faulty TCM can manifest in several ways. From my 20+ years of experience, these are the tell-tale signs I see in the shop every week. Check if any of these symptoms sound familiar:
- ✔ Harsh, slamming shifts or jerky gear engagement.
- ✔ The vehicle is stuck in “limp mode” (usually 2nd or 3rd gear).
- ✔ Check Engine Light or Transmission Warning Light is on with codes like P0700 (TCM Requesting MIL), P0750-P0758 (Shift Solenoid Faults), or other transmission-related DTCs.
- ✔ Failure to upshift or downshift, causing poor acceleration and terrible fuel economy.
- ✔ A significant delay when shifting from Park into Drive or Reverse.
- ✔ Unexplained loss of communication with the transmission module on a scan tool.
Case Study: A Tricky Diagnosis
A customer brought in a 2008 Trailblazer with classic limp-mode symptoms. Another shop had quoted them over $3,000 for a transmission rebuild, assuming internal mechanical failure. However, the diagnostic codes were pointing to intermittent solenoid circuit faults across multiple gears—a classic sign of electronic, not mechanical, failure. I’ve seen this exact pattern hundreds of times. We connected our scanner and confirmed communication with the TCM was dropping out. Instead of a costly rebuild, we installed a VIN-programmed T42 module. The total repair took less than an hour and saved the customer thousands. This is why properly diagnosing the TCM first is critical.
Why Our VIN-Programmed Module is the Smart Fix
- ✔ No Dealership Required: This module is expertly programmed with the latest GM software updates for your Trailblazer’s VIN. This bypasses the need for expensive dealer tools or programming fees. It’s ready to install right out of the box.
- ✔ Targeted Solution: Specifically designed to resolve common T42 TCM failures, clearing persistent diagnostic trouble codes and restoring precise electronic control over the 4L60E, 4L65E, or 4L70E transmission.
- ✔ OEM-Standard Reliability: Built to meet or exceed original equipment specifications for durability and performance. It’s backed by our one-year warranty for your peace of mind.
- ✔ No Core Charge: Keep your old part. There’s no core charge and no hassle of shipping the old module back.
Your Step-by-Step Installation Guide
For the 2006-2009 Trailblazer, this is a job most DIYers can handle in their driveway in under 30 minutes.
- Safety First: Disconnect the negative terminal from your vehicle’s battery to prevent any electrical shorts.
- Locate the TCM: On the Trailblazer and Envoy, the TCM is typically found in the engine compartment on the driver’s side (LH side).
- Disconnect and Remove: Carefully unplug the electrical connectors from the old TCM. Then, unbolt the module from its mounting bracket.
- Install the New Module: Bolt the new VIN-programmed TCM into place and securely reconnect the electrical connectors. Ensure they click into place.
- Final Steps: Reconnect the negative battery terminal. While the module is plug-and-play, it’s best 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 Vehicle Compatibility
This T42 Transmission Control Module is a direct fit for the 2006-2009 Chevrolet Trailblazer (including models with the 8-cylinder engine). It also fits a wide range of other GM vehicles. Please verify your model and options below. Interchangeable with part numbers: 24252114, 24234503, 24230461, 24234274, 24235340, 24235754, 24238856, 24239224, 24239926, 24240400, 24241806, 24243901, 24243921, 24252114, 24255280, 24256960, and more.
This part will fit these makes and models with these options
TRAILBLAZER 08-09 Transmission; (LH engine compartment)
TRAILBLAZER 06-07 Transmission; (LH engine compartment), (8 cylinder)
TRAILBLAZER EXT 06 Transmission; (LH engine compartment), (8 cylinder)
ENVOY 08-09 Transmission; (LH engine compartment)
ENVOY 06-07 Transmission; (LH engine compartment), (8 cylinder)
ENVOY XL 06 Transmission; (LH engine compartment), (8 cylinder)
SAAB 9-7X 06-09 Transmission; (LH engine compartment)
RAINIER 06-07 Transmission
… and many other GM vehicles listed in the original data.
Frequently Asked Questions
What exactly does VIN programming do for my Trailblazer?
VIN programming loads your vehicle’s specific factory software and calibration files onto the module. This ensures the TCM works perfectly with your Trailblazer’s engine, options, and transmission type, making it a true plug-and-play installation without needing a trip to the dealer.
Do I need any special tools to install this part?
No special tools are required. Basic hand tools (like a socket set) to remove the mounting bolts are all you need. An OBD2 scanner is recommended to clear old codes after installation, but it is not required for the module to function.
Will this 2006-2009 Trailblazer TCM fix a P0700 trouble code?
Often, yes. A P0700 code is a general code meaning the TCM has detected a fault and has requested the check engine light be turned on. This programmed TCM is designed to fix the underlying electronic faults that cause the TCM to set the P0700 code in the first place.
Is this a new or used part?
This is a high-quality, OEM-standard component that has been inspected and programmed to ensure it meets or exceeds original performance. It is backed by a one-year warranty for your protection.
Where is the TCM located on my 2007 Trailblazer?
On the 2006-2009 Chevrolet Trailblazer, the Transmission Control Module (TCM) is located in the engine bay, on the driver’s side (LH side), mounted near the firewall or inner fender.