If you’re dealing with the frustration of a transmission that won’t shift correctly, you’re not alone. As a technician with over two decades of experience, I’ve seen countless GM vehicles, like the 2006 Trailblazer EXT, come into the shop with symptoms that owners fear mean a costly transmission rebuild. More often than not, the culprit is a faulty Transmission Control Module (TCM). This VIN-programmed T42 TCM, part number 24240400, is the direct, reliable solution to restore your vehicle’s performance and your peace of mind.
This isn’t just a replacement part; it’s a complete fix. The TCM is the brain of your automatic transmission, managing everything from shift points and line pressure to torque converter lockup. When it fails, communication breaks down, leading to the jarring shifts, delayed engagement, or ‘limp mode’ that makes driving a nerve-wracking experience. Our module arrives pre-programmed to your vehicle’s specific VIN, eliminating the need for an expensive trip to the dealership for programming. It’s a true plug-and-play repair that you can perform right in your own driveway.
From the Diagnostic Bay: More Than Just a Bad Shift
I remember a customer with a 2006 Trailblazer EXT who was ready to sell it for scrap. The truck would randomly slam into gear and the check engine light was constantly on with a P0700 code. He was quoted thousands for a new transmission. I hooked up my scan tool and saw erratic data from the shift solenoids. Instead of condemning the transmission, I checked the TCM. After installing one of our pre-programmed modules—a 30-minute job—the shifting was perfectly smooth, and all codes were gone. He saved a fortune and kept his truck. This is the power of a correct diagnosis and a quality part.
Is Your Trailblazer Exhibiting These Symptoms?
A failing TCM can manifest in several ways. If you’re noticing any of the following, it’s a strong indicator that your module needs replacement. Addressing it now can prevent further damage to your transmission’s mechanical components.
- ✔ Harsh, erratic, or delayed gear shifts.
- ✔ Vehicle is stuck in one gear (often called limp mode).
- ✔ Check Engine Light or Transmission Warning Light is illuminated.
- ✔ Diagnostic Trouble Codes (DTCs) are present, such as P0700, P0750, or other solenoid-related faults.
- ✔ Poor fuel economy and a feeling of lost power.
- ✔ Complete loss of communication with the TCM.
The Definitive Fix for Your 2006 Trailblazer EXT TCM
This module is engineered to OEM specifications to ensure perfect communication with your vehicle’s powertrain. By providing us with your VIN, we flash the module with the latest GM software updates specific to your Trailblazer EXT. This ensures that all shift strategies and operational parameters are perfectly matched, restoring the smooth, predictable performance you expect. It is a direct replacement for part numbers 24240400, 24252114, 24234503, and others listed below.
A Straightforward Guide to Installation
You don’t need to be a master mechanic to install this part. With basic tools, you can have your vehicle back on the road in under an hour.
- Safety First: Disconnect the negative terminal from your vehicle’s battery to prevent any electrical shorts and to help reset the system.
- Locate the TCM: On your 2006 Trailblazer EXT, the TCM is typically found in the engine compartment on the left-hand (driver’s) side.
- Disconnect and Remove: Carefully unplug the electrical connectors. Be gentle with the locking tabs. Then, unbolt the module from its mounting bracket.
- Install the New Module: Bolt the new, pre-programmed TCM into place and securely reconnect the electrical harnesses. You should hear a ‘click’ as they lock.
- Final Steps: Reconnect the battery terminal. Start the vehicle and let it idle for a few minutes. Use a basic OBD2 scanner to clear any stored fault codes if they persist.
Verified Vehicle Compatibility
This T42 Transmission Control Module is guaranteed to fit the following vehicles, among many others. Please verify your part number for a perfect match.
This part will fit these makes and models with these options
ENVOY 08-09 Transmission; (LH engine compartment)
SAVANA 3500 VAN 06-14 Transmission; (RH engine compartment)
VUE 07-08 Transmission; 2.4L, (LH front engine compartment)
G5 07-10 Transmission; (LH strut tower)
SIERRA 1500 PICKUP 07 Transmission; (new style, smooth door skin), (next to battery)
LUCERNE 06-07 Transmission; (4.6L), (LH engine compartment)
VUE 09 Transmission; 2.4L, w/hybrid, LH side front engine compartment, (shift control)
VUE 10 Transmission
TAHOE 08-09 Transmission; (next to battery), w/o auxiliary oil cooler pump
YUKON XL 1500 07-08 Transmission; (next to battery)
AURA 07-09 Transmission; (LH frame rail front)
RENDEZVOUS 06-07 Transmission; (air cleaner box)
SAAB 9-7X 06-09 Transmission; (LH engine compartment)
SAVANA 2500 VAN 06-14 Transmission; (RH engine compartment)
ALLURE 06-09 Transmission; (lower air cleaner housing)
LUCERNE 08-11 Transmission; (LH engine compartment)
RAINIER 06-07 Transmission
SILVERADO 1500 PICKUP 07 Transmission; (new style, smooth door skin), (next to battery)
SILVERADO 1500 PICKUP 09-13 Transmission; (next to battery), w/o hybrid option
YUKON 09 Transmission; (next to battery), w/o auxiliary oil cooler pump
ENVOY 06-07 Transmission; (LH engine compartment), (8 cylinder)
MONTE CARLO 06-07 Transmission; (lower air cleaner housing)
YUKON 08 Transmission; (next to battery), w/o auxiliary oil cooler control
EXPRESS 1500 VAN 06-14 Transmission; (RH engine compartment)
SSR 05-06 Transmission; (front LH frame)
SAVANA 1500 VAN 06-14 Transmission; (RH engine compartment)
SIERRA 1500 PICKUP 09-13 Transmission; (next to battery), w/o hybrid option
EXPRESS 3500 VAN 06-14 Transmission; (RH engine compartment)
ION 06-07 Transmission; (behind LH strut tower)
PURSUIT 06 Transmission; (LH strut tower)
TAHOE 07 Transmission; (next to battery)
ENVOY XL 06 Transmission; (LH engine compartment), (8 cylinder)
EXPRESS 2500 VAN 06-14 Transmission; (RH engine compartment)
IMPALA 06-11 Transmission; (lower air cleaner housing)
MONTANA 06-09 Transmission; (LH strut tower)
TRAILBLAZER 08-09 Transmission; (LH engine compartment)
YUKON 07 Transmission; (next to battery)
G6 06-10 Transmission; (LH strut tower)
HHR 06-11 Transmission; (LH engine compartment)
TRAILBLAZER 06-07 Transmission; (LH engine compartment), (8 cylinder)
AVALANCHE 1500 07-08 Transmission; (next to battery)
COBALT 06-10 Transmission; (LH strut tower)
SIERRA 1500 PICKUP 08 Transmission; (next to battery)
SILVERADO 1500 PICKUP 08 Transmission; (next to battery)
LACROSSE 06-09 Transmission; (lower air cleaner housing)
SIERRA 2500 PICKUP 07 Transmission; new style (smooth door skin), 6.0L, (next to battery)
SILVERADO 2500 PICKUP 07 Transmission; new style (smooth door skin), 6.0L, (next to battery)
COLORADO 08-12 Transmission; (RH rear engine compartment)
SUBURBAN 1500 07-08 Transmission; (next to battery)
VUE 09 Transmission; 2.4L, w/o hybrid; (LH front engine compartment)
CANYON 08-12 Transmission; (RH rear engine compartment)
DTS 06-11 Transmission; (RH front engine compartment)
MALIBU 06-10 Transmission; (LH frame rail)
GRAND PRIX 06-08 Transmission; (lower air cleaner housing)
HUMMER H3 08-10 Transmission; (RH rear engine compartment)
TERRAZA 06-07 Transmission; (LH strut tower)
TRAILBLAZER EXT 06 Transmission; (LH engine compartment), (8 cylinder)
UPLANDER 06-09 Transmission; (LH strut tower)
Frequently Asked Questions
Is this part really plug-and-play?
Yes. We program the module to the VIN you provide during checkout. This ensures it works with your vehicle’s specific configuration right out of the box, with no additional programming needed.
Do I need to return my old TCM?
No, there is no core charge for this part. You can keep your old module or dispose of it responsibly without any hassle or extra cost.
Will this fix a P0700 trouble code?
A P0700 code is a general fault request from the TCM. While a failing TCM is a very common cause, this code indicates that a more specific transmission code is stored. This module often resolves the underlying issue causing the P0700, but you should scan for all codes for a complete diagnosis.
Where is the TCM located on my 2006 Trailblazer EXT?
On the 2006 Trailblazer EXT with the 8-cylinder engine, the Transmission Control Module is located in the engine compartment, on the driver’s side (LH side).