Restore Peak Performance to Your GM Truck or SUV
Is your 2006 Buick Rainier, Trailblazer, or Envoy suffering from erratic behavior, poor fuel economy, or a persistent Check Engine Light? The Powertrain Control Module (PCM), often called the Engine Control Module (ECM), is the central computer responsible for managing your vehicle’s engine and transmission. When it begins to fail, it can cause a cascade of frustrating and difficult-to-diagnose issues. This replacement PCM, part number 12606399, is the definitive solution to restore your vehicle’s original performance, drivability, and reliability.
As the brain of your vehicle, the PCM processes data from dozens of sensors to control critical functions like fuel injection, ignition timing, transmission shifting, and emissions systems. Over time, heat, vibration, and electrical fluctuations can degrade internal components, leading to incorrect calculations and poor engine management. Replacing a faulty module is not just about turning off a light on your dash; it’s about restoring the precise engineering that makes your vehicle run smoothly and efficiently.
From the Diagnostic Bay
We had a 2006 Trailblazer come into the shop with what the owner was convinced was a failing transmission. It was shifting harshly between first and second gear and occasionally seemed to get ‘stuck’ in a high gear, forcing a restart. He had already spent a significant amount of money at a transmission shop that couldn’t find a mechanical fault. After plugging in our scanner, we noticed erratic data coming from the PCM to the transmission control solenoids. Instead of a costly transmission rebuild, the root cause was a failing driver circuit inside the original engine computer. We installed a VIN-programmed PCM, performed the security relearn, and the truck shifted perfectly. It’s a classic case of the brain (PCM) sending bad signals to the body (transmission), and a reminder to always check the control module first for complex shifting problems.
Common Symptoms of a Failing Powertrain Control Module
- ✔ Check Engine Light: The most common indicator, often with codes related to sensors, emissions, or internal module failure.
- ✔ Poor Fuel Economy: Incorrect fuel and air calculations can cause the engine to run too rich or too lean, drastically reducing MPG.
- ✔ Engine Stalling or Misfiring: The PCM controls spark and fuel. A fault can lead to random stalling, rough idling, or misfires.
- ✔ No-Start Condition: The vehicle may crank but fail to start if the PCM isn’t properly managing the ignition or fuel systems.
- ✔ Harsh or Failed Transmission Shifting: The PCM works with the TCM to control shift points. A bad PCM can cause jerky shifts, delayed engagement, or the transmission going into ‘limp mode’.
- ✔ Failed Emissions Test: If the PCM cannot properly manage the engine’s emissions systems, your vehicle will not pass inspection.
- ✔ Communication Errors: Diagnostic scan tools may be unable to communicate with a failing PCM.
The Plug-and-Play Solution for Your 2006 Rainier PCM
Don’t settle for a generic, unprogrammed module that requires expensive dealership tools and labor. We take the guesswork out of the repair. When you purchase this module, you provide us with your vehicle’s 17-digit Vehicle Identification Number (VIN). Our technicians will then program the unit with the latest GM-certified software specific to your exact vehicle build. This ensures that the PCM recognizes all your vehicle’s options, security systems, and operational parameters right out of the box. This VIN-specific programming is critical for proper function and avoids the compatibility issues that plague non-programmed modules.
Installation is straightforward for a DIY mechanic or any professional technician. Once installed, you will need to perform a simple security relearn procedure (often called a CASE relearn or anti-theft relearn), which pairs the new computer to your vehicle’s keys. This procedure typically takes 10-30 minutes and does not require any special tools. Instructions are readily available online or in service manuals for your specific model.
Guaranteed Fitment and Compatibility
This Powertrain Control Module is a direct replacement for a wide range of GM trucks and SUVs. It is compatible with 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. Please verify your part number before ordering to ensure a perfect match.
This part will fit these makes and models with these options:
- ✔ BUICK RAINIER 2006: Electronic Control Module; (LH engine), 4.2L
- ✔ CHEVROLET COLORADO 2004-2006: Electronic Control Module; (RH firewall)
- ✔ CHEVROLET TRAILBLAZER 2006: Electronic Control Module; (LH engine), 4.2L
- ✔ CHEVROLET TRAILBLAZER EXT 2006: Electronic Control Module; (LH engine), 4.2L
- ✔ GMC CANYON 2004-2006: Electronic Control Module; (RH firewall)
- ✔ GMC ENVOY 2006: Electronic Control Module; 4.2L (LH engine)
- ✔ GMC ENVOY XL 2006: Electronic Control Module; (LH engine), 4.2L
- ✔ HUMMER H3 2006: Electronic Control Module; (RH firewall)
- ✔ ISUZU ASCENDER 2006: Electronic Control Module; 4.2L (LH engine)
- ✔ ISUZU I-280 2006: Electronic Control Module; (RH firewall)
- ✔ ISUZU I-350 2006: Electronic Control Module; (RH firewall)
- ✔ SAAB 9-7X 2006: Electronic Control Module; (LH engine), 6 cylinder, ID 12569773 or 12597521
Frequently Asked Questions
Do I need to do anything after installing this PCM?
Yes. While the module comes programmed to your VIN, you must perform a security relearn procedure. This syncs the new PCM with your vehicle’s anti-theft system and keys. This procedure can typically be done without special tools and instructions are widely available for your vehicle.
Where do I provide my VIN?
After you complete your purchase, you will receive instructions on how to send us your 17-digit VIN. We cannot ship your part until we receive and validate your VIN, as the programming is essential for the part to function.
Is this a brand new part?
This is a high-quality, OEM replacement part that has been thoroughly inspected and tested to meet or exceed original factory specifications. It is programmed with the latest software from GM for optimal performance.
Will this fix my specific problem?
This PCM will correct issues directly caused by a faulty module. It is crucial to have your vehicle properly diagnosed by a professional to ensure the PCM is the root cause of your problem, as other failing sensors or wiring issues can cause similar symptoms.
What is the warranty on this module?
This part comes with a standard warranty against defects in materials and workmanship. Please refer to our store’s warranty policy page for complete details and duration.