Restore Your Truck’s Performance with a VIN-Programmed PCM
Is your 2006 GMC Envoy XL running rough, stalling unexpectedly, or showing a persistent Check Engine Light? These are classic signs of a failing Powertrain Control Module (PCM), the electronic brain of your vehicle. A faulty PCM can disrupt everything from fuel delivery and ignition timing to transmission shifting, making your truck unreliable. This isn’t just an inconvenience; it’s a critical component for your vehicle’s safety and efficiency. This listing offers a dependable, direct-fit solution: a replacement 2006 Envoy XL PCM, professionally programmed with the latest GM software updates specifically for your vehicle’s VIN.
Case Study: A Tricky Diagnosis
I remember a 2006 Trailblazer—which shares this exact PCM with the Envoy—that came into my bay with a frustrating, intermittent no-start condition. The owner had already replaced the battery and starter. Scans showed no consistent codes, just a random collection of communication errors that would appear and disappear. After checking grounds and wiring harnesses for hours, we decided to monitor the PCM’s live data during a startup attempt. We caught it: the 5-volt reference signal would drop out for just a split second, killing the engine before it could fully start. It was an internal PCM fault, something you’d never find with a simple visual inspection. Swapping in a pre-programmed module like this one had the truck firing up perfectly every time. It saved the customer hundreds in further diagnostic fees and solved a problem that had been plaguing them for months.
Is Your Envoy Showing These Signs of PCM Failure?
A failing engine computer can cause a wide range of symptoms. If you’re experiencing any of the following, a faulty PCM is a likely culprit. In my 20+ years of experience, these are the most common indicators I’ve seen in the shop:
- ✔ Check Engine Light is on with diagnostic trouble codes (DTCs) like P0601 (Internal Control Module Memory Check Sum Error), P0605 (Read Only Memory Error), or P0606 (PCM Processor Fault).
- ✔ The engine cranks but refuses to start.
- ✔ Unexplained stalling or rough idling, especially when warm.
- ✔ Noticeable decrease in fuel economy.
- ✔ Harsh or erratic automatic transmission shifting.
- ✔ Failure to pass an emissions test.
Your Straightforward PCM Installation Guide
One of the biggest advantages of this module is that it arrives ready for installation, with no dealership visit required for programming. This makes it a perfect job for a DIY enthusiast. Here’s a general guide to get you started:
- Safety First: Always disconnect the negative terminal from your vehicle’s battery before starting any electrical work.
- Locate the PCM: On the 2006 Envoy XL with the 4.2L engine, the PCM is typically located on the driver’s side of the engine compartment, mounted to the inner fender.
- Disconnect the Connectors: Carefully release the locking tabs on the electrical harness connectors and pull them straight out from the module. Avoid pulling on the wires themselves.
- Remove the Old Module: Unbolt the old PCM from its mounting bracket. There are usually two or three bolts holding it in place.
- Install the New Module: Mount your new, pre-programmed PCM onto the bracket and securely fasten the bolts.
- Reconnect Everything: Plug the electrical connectors back into the new PCM, ensuring they click into place. Reconnect your battery’s negative terminal.
- Final Step: In some cases, a security relearn procedure may be needed, which can typically be done without special tools. Simply turn the key to the ‘ON’ position for 10-15 minutes, then ‘OFF’, and repeat two more times before starting the engine.
Verified Vehicle Compatibility
This module is a direct replacement for part number 12597521 and a wide range of other interchangeable part numbers. It is guaranteed to fit the following vehicles and configurations:
- 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 unit is also a direct replacement for the following part numbers: 12569773, 12588650, 12589311, 12589585, 12591647, 12591648, 12593531, 12593532, 12594430, 12594431, 12596783, 12596784, 12597776, 12597777, 12600818, 12604438, 12604439, 12606369, 12606373, 12606374, 12606398, 12606399, 19209820, 19209821.
Frequently Asked Questions
Frequently Asked Questions
Why do you need my VIN?
Your Vehicle Identification Number (VIN) allows us to load the exact, correct software from GM for your truck’s specific options and configuration. This ensures perfect compatibility and function right out of the box.
Is any additional programming needed after installation?
No. This 2006 Envoy XL PCM arrives fully programmed to your VIN. In most cases, it is a plug-and-play installation, though some vehicles may require a simple security relearn procedure that you can do yourself in about 30 minutes.
Where can I find my VIN?
Your 17-digit VIN can be found on your vehicle’s registration, your insurance card, or on a small plate on the driver’s side of the dashboard, visible through the windshield.
What if my original part number isn’t 12597521?
GM often uses many different part numbers for the same component. As long as your vehicle is listed in our compatibility chart, this module will work for you. We program it based on your VIN, not the old part number.
Is this a used part?
This is a high-quality, inspected, and tested replacement part that has been programmed with the latest software to ensure reliability and performance that meets or exceeds the original factory standards.