Is Your 2006 Trailblazer or GM SUV Running Rough?
As a technician with over two decades of experience under the hood, I’ve seen it all when it comes to the GM GMT360 platform (Trailblazer, Envoy, Rainier, etc.). When the Powertrain Control Module (PCM) starts to fail, the symptoms can be confusing and frustrating. Your reliable truck might suddenly feel like it has a mind of its own.
You might be experiencing issues that have you scratching your head, swapping parts, and still ending up with a check engine light glaring back at you. If your 2006 Trailblazer is on the fritz, a failing PCM is a very common culprit.
Common Symptoms of a Failing 2006 Trailblazer PCM
In my shop, I’ve diagnosed hundreds of these specific PCMs. The issues aren’t always a simple ‘no-start’ condition. Often, they’re intermittent and maddening. Look out for:
- ✔ Unexplained Check Engine Light (CEL) with various communication or processor codes.
- ✔ Harsh or erratic transmission shifting.
- ✔ Engine stalling randomly, especially when coming to a stop.
- ✔ A complete no-start condition where the engine cranks but won’t fire up.
- ✔ Poor fuel economy that seems to have appeared overnight.
- ✔ Misfire codes that persist even after replacing spark plugs and ignition coils.
- ✔ Loss of communication with your scan tool.
Expert Pro Tip: Check Your Grounds First!
Before you condemn your PCM, do yourself a favor and check the main engine-to-chassis ground strap. On these Trailblazers, it’s often located near the PCM on the driver’s side of the engine block. I’ve seen countless cases where a corroded or loose ground causes voltage issues that mimic a bad computer. A few minutes with a wire brush can save you a lot of time and money. Always verify power and ground integrity at the PCM connectors before replacing the unit.
The Plug-and-Play Solution: Your Pre-Programmed PCM
This isn’t just a replacement part; it’s a complete solution. We take a genuine GM module and flash it with the latest, most stable software calibration for your specific vehicle. The key is your Vehicle Identification Number (VIN). When you provide us with your VIN at checkout, we ensure the module that arrives at your door is 100% matched to your Trailblazer’s factory settings and options.
What does this mean for you?
- ✔ No Dealer Visit Required: You avoid the hassle and high cost of having a dealership program a new module.
- ✔ No Special Tools Needed: The programming is done. All you need are basic hand tools for the physical installation.
- ✔ Latest GM Updates: Your module comes loaded with software improvements from GM that often resolve factory drivability quirks.
- ✔ Direct-Fit Replacement: This module is guaranteed to fit and function correctly, restoring your vehicle’s performance.
Installation & Security Relearn
On the 2006 Trailblazer with the 4.2L engine, the PCM is located on the driver’s side of the engine bay, bolted to the block. After disconnecting the battery, you’ll simply unbolt the old unit, carefully disconnect the wiring harnesses, and install the new one in its place.
After installation, you will need to perform a simple security relearn procedure (often called the GM Passlock or Passkey relearn) so the new PCM recognizes your key. This takes about 30 minutes and requires no tools:
- Turn the key to the “ON” position (don’t start the engine).
- Wait about 10-15 minutes, or until the “Security” light on the dash turns off.
- Turn the key to “OFF” for 10 seconds.
- Repeat steps 1-3 two more times for a total of three cycles.
- The vehicle should now start and run with the new PCM.
Guaranteed Fitment For Your Vehicle
This Powertrain Control Module is a direct replacement for the following vehicles and part numbers. Please verify your model and engine to ensure compatibility.
This module fits:
- ✔ Buick Rainier: 2006 (4.2L)
- ✔ Chevrolet Trailblazer & Trailblazer EXT: 2006 (4.2L)
- ✔ Chevrolet Colorado: 2004, 2005, 2006
- ✔ GMC Envoy, Envoy XL, Envoy XUV: 2006 (4.2L)
- ✔ GMC Canyon: 2004, 2005, 2006
- ✔ Hummer H3: 2006
- ✔ Isuzu Ascender: 2006 (4.2L)
- ✔ Isuzu i-280 & i-350: 2006
- ✔ Saab 9-7x: 2006 (6-cylinder)
Replaces Part Numbers: 12569773, 12588650, 12589311, 12589585, 12591647, 12591648, 12593531, 12593532, 12594430, 12594431, 12596783, 12596784, 12597521, 12597776, 12597777, 12600818, 12604438, 12604439, 12606369, 12606373, 12606374, 12606398, 12606399, 19209820, 19209821