End the Guesswork and Get Your Trailblazer Running Right
Is your 2006 Trailblazer EXT giving you headaches? A flickering check engine light, frustrating stalling, rough idling, or a sudden drop in fuel economy are more than just annoyances—they’re signs that the brain of your engine, the Powertrain Control Module (PCM), might be failing. It’s a frustrating position to be in, leaving you questioning your vehicle’s reliability. This isn’t just a part; it’s the solution to restore your confidence and bring back that smooth, dependable drive you rely on.
This replacement PCM, compatible with part number 12591647, arrives at your door fully programmed to your vehicle’s specific Vehicle Identification Number (VIN). We handle the complex part, flashing it with the latest GM software updates, so you can avoid a costly trip to the dealership. The result is a straightforward installation that gets you back on the road quickly and with peace of mind.
Signs Your Engine Computer Needs Attention & The Benefits of This Solution
- ✔ Clears Persistent Check Engine Lights: Finally resolve stubborn diagnostic trouble codes (DTCs) like P0601, P0602, P0606, or other internal processor faults.
- ✔ Restores Smooth Performance: Eliminates rough idling, hesitation, and stalling by ensuring precise fuel and ignition timing.
- ✔ Fixes Erratic Shifting: Corrects communication errors with the transmission module for smooth, predictable gear changes.
- ✔ Solves No-Start Conditions: Addresses PCM-related issues that prevent the engine from starting, especially when all other components check out.
- ✔ Improves Fuel Economy: A properly functioning computer optimizes the air-fuel mixture, helping you regain lost MPG.
- ✔ Plug-and-Play Installation: Because we program it to your VIN, it’s ready to install right out of the box, with no additional programming required.
Guided Installation for Your 2006 Trailblazer EXT PCM
Replacing the PCM is a manageable job for a confident DIYer. Follow these steps for a successful installation and get back to a worry-free drive.
- Safety First: Always disconnect the negative terminal from your vehicle’s battery and wait at least 10-15 minutes to allow the system’s capacitors to discharge.
- Locate the Old Module: On your 2006 Trailblazer, the PCM is typically located on the driver’s side of the engine compartment, mounted to the inner fender or firewall.
- Disconnect the Connectors: Carefully release the locking tabs on the electrical harness connectors and gently pull them straight out. Never force them. Inspect the connectors for any corrosion or bent pins.
- Remove the Old PCM: Unbolt the mounting hardware holding the old computer in place and remove it from the vehicle.
- Install the New PCM: Mount your new, pre-programmed PCM in the same location and secure it with the original hardware.
- Reconnect Everything: Firmly plug the electrical connectors back into the new module until they click into place. Reconnect the negative battery terminal.
- Perform a Relearn (If Necessary): While not always required, you may need to perform a security or crank-relearn procedure. For many vehicles, simply cycling the key from ‘Off’ to ‘On’ a few times and starting the engine is all that’s needed. Let it idle for a few minutes to adapt.
An Expert’s Note: The Power of a Clean Connection
“I once worked with a customer who was on his last nerve with a persistent intermittent stalling issue on his Envoy. He had replaced sensors and checked wiring for weeks. When his new PCM arrived, I reminded him to take an extra 60 seconds to clean the main engine-to-chassis ground strap with a wire brush until it was shiny. A poor ground can cause voltage drops that mimic a failing computer. He installed the new module with a clean ground, and the truck ran perfectly. It’s a small step that provides huge insurance for any electronic repair.”
Tailored Fit for Your GM Vehicle
This Powertrain Control Module is a direct-fit replacement for a range of GM trucks and SUVs. Please verify your part number and vehicle from the list below to ensure perfect compatibility:
- Buick Rainier: 2006 (4.2L)
- Chevrolet Colorado: 2004-2006
- Chevrolet Trailblazer & Trailblazer EXT: 2006 (4.2L)
- GMC Canyon: 2004-2006
- GMC Envoy & Envoy XL: 2006 (4.2L)
- Hummer H3: 2006
- Isuzu Ascender: 2006 (4.2L)
- Isuzu i-280 & i-350: 2006
- Saab 9-7x: 2006 (6 cylinder)
This module replaces numerous part numbers, including: 12569773, 12588650, 12589311, 12591647, 12596783, 12597521, 12604438, 19209820, and more.
Frequently Asked Questions
Do I need to do anything after I install it?
In most cases, no. Since we program the PCM to your VIN, it’s ready to go. Some vehicles may require a simple security relearn procedure, which can often be done by cycling the key in the ignition. We include general instructions to guide you.
How do I provide my VIN?
After you complete your purchase, you will receive instructions on how to send us your vehicle’s 17-digit VIN. We cannot ship your part until we receive this information, as the programming is specific to your vehicle.
Is this a guaranteed fix for my vehicle’s problems?
This PCM will correct any issues directly caused by a faulty engine computer. However, it’s crucial to ensure your vehicle has been properly diagnosed. This part will not fix problems caused by other faulty components, such as bad sensors, wiring issues, or mechanical failures.
What if my original part number isn’t listed?
The part numbers listed are the most common ones this module replaces. If your vehicle model and year are listed in our compatibility chart, this module will likely work. Please contact us with your VIN and original part number to confirm compatibility before ordering.
What is the benefit of getting the latest GM software?
Manufacturers often release software updates to address common issues, improve transmission shifting logic, and enhance engine efficiency. By flashing your module with the newest updates, you’re getting a solution that is often better than the one that originally came with your vehicle.