Is your 2006 GMC Envoy XL running rough, stalling unexpectedly, or showing a persistent check engine light? These frustrating issues often point to one component: a failing Powertrain Control Module (PCM), the electronic brain of your vehicle. When it starts to fail, it can cause a cascade of problems that are difficult to diagnose. This isn’t just an inconvenience; it’s a reliability issue that can leave you stranded. Stop chasing electronic gremlins and get the definitive solution.
This is a direct-replacement PCM, specifically for your vehicle, that arrives at your door fully programmed with the latest GM software updates. We take your vehicle’s VIN and flash the module before it ships, making installation a true plug-and-play process. You can bypass the expensive dealership visit, saving you hundreds of dollars in programming fees and the hassle of getting your vehicle towed. This is the same quality and functionality you’d expect from the factory, made simple and affordable for both professional mechanics and DIY enthusiasts.
Case Study: A Tricky Diagnosis
A customer brought in a 2006 Trailblazer—the sister vehicle to the Envoy—with a complaint that stumped two other shops. It had an intermittent no-start condition with no rhyme or reason. Sometimes it would fire right up, other times it would just crank. We scanned it and found a U0100 ‘Lost Communication with ECM/PCM’ code stored. After verifying the power and ground circuits to the module were solid (a critical first step!), we knew the issue was internal to the computer. The intermittent nature was classic for a failing 2006 Envoy XL PCM, where heat cycles cause internal solder joints to fail. We installed one of our pre-programmed modules, and the truck has been starting reliably ever since. This simple swap saved the customer from replacing more parts unnecessarily.
Common Signs of a Failing Engine Computer
- ✔ Check Engine Light is on with communication codes (like U0100) or internal processor fault codes (P0601, P0606).
- ✔ Your vehicle fails to start or stalls intermittently.
- ✔ Noticeable decrease in fuel economy for no apparent reason.
- ✔ Harsh or erratic automatic transmission shifting.
- ✔ The engine runs rough, misfires, or hesitates during acceleration.
- ✔ Failure to pass state emissions testing.
A Straightforward Guide to Installation
- ✔ Safety First: Always disconnect the negative terminal from your vehicle’s battery before beginning any work on the electrical system.
- ✔ Locate the PCM: On the 2006 Envoy XL with the 4.2L engine, the PCM is located in the engine bay on the driver’s side (LH side), mounted to the inner fender.
- ✔ Disconnect and Remove: Carefully unplug the electrical connectors. There are typically release tabs that need to be depressed. Once disconnected, unbolt the module from its mounting bracket.
- ✔ Install the New Module: Bolt the new, pre-programmed PCM into place. Reconnect the electrical harnesses, ensuring they click securely into position.
- ✔ Reconnect Battery: Reattach the negative battery terminal and tighten it.
- ✔ Perform Security Relearn: You may need to perform a simple key-cycle relearn procedure. Typically, this involves turning the key to the ‘ON’ position for 10-15 minutes, then ‘OFF’ for 10 seconds, and repeating two more times. This allows the vehicle’s anti-theft system to recognize the new PCM. Then, start the engine.
Verified Vehicle Compatibility
This module is a direct replacement for part number 12597521 and other interchangeable numbers listed below. It is guaranteed to fit the following vehicles:
- 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: 2006
- Isuzu i-350: 2006
- Saab 9-7X: 2006 (6-Cylinder)
This module replaces the following 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.
Frequently Asked Questions
Why do you need my VIN?
Your Vehicle Identification Number (VIN) is essential for us to program the PCM with the exact software and calibrations specific to your Envoy XL’s engine, transmission, and factory options. This ensures perfect compatibility and performance right out of the box.
Is any additional programming required after installation?
No. This module is delivered fully programmed. The only step you may need to perform is a simple security relearn procedure, which involves a few key cycles and requires no special tools. We include instructions for this process.
What if my original part number isn’t on the list?
The part numbers listed are the most common ones this module replaces. If your number is different, please contact us with your VIN. We can verify compatibility to ensure you receive the correct part for your vehicle.
Will this fix my vehicle’s specific problem?
This PCM will correct issues directly caused by a faulty module, such as internal processor errors, communication faults, and driver circuit failures. While it solves the most common electronic problems, you should always ensure your vehicle’s issues are not caused by bad wiring, sensors, or other components.
Where is the PCM located on my truck?
For the 2006 GMC Envoy XL and other Trailblazer-platform vehicles with the 4.2L engine, the PCM is typically mounted to the inner fender on the driver’s side of the engine bay. For models like the Colorado or Canyon, it’s often on the passenger side firewall.