Is Your 2006 Envoy Running Rough? The PCM Might Be the Culprit.
If your 2006 GMC Envoy is experiencing perplexing issues like stalling, erratic shifting, a persistent check engine light, or a no-start condition, the root cause is often the vehicle’s central computer: the Powertrain Control Module (PCM). As the brain of your vehicle, the PCM controls everything from fuel mixture and ignition timing to transmission shift points and emissions systems. When it fails, it can create a cascade of problems that are often misdiagnosed, leading to wasted time and money on unnecessary repairs.
This replacement Powertrain Control Module is the definitive solution to restore your vehicle’s performance and reliability. We take the guesswork out of the repair by pre-programming this unit specifically for your vehicle using your VIN. This ensures that it has the correct calibration and the latest software updates directly from GM, making the installation process as straightforward as possible.
From the Diagnostic Bay
We had a 2006 Trailblazer (which shares the same platform as the Envoy) come into the shop with a complaint of random stalling and harsh shifting. The owner had already replaced the throttle body and a couple of sensors with no luck. After hooking up our diagnostic tools, we noticed erratic data streams coming from the PCM. The internal processors were failing, sending incorrect commands to the engine and transmission. Instead of continuing to chase ghosts, we installed a VIN-programmed PCM like this one. The difference was immediate. The engine idled smoothly, the transmission shifted perfectly, and the check engine light was gone for good. It’s a classic case where addressing the core problem—the computer—saved the customer from further frustration and expensive part-swapping.
Common Symptoms of a Failing PCM
- ✔ Persistent Check Engine Light (CEL) with various trouble codes.
- ✔ Engine stalling, stumbling, or hesitating during acceleration.
- ✔ Rough or inconsistent idling.
- ✔ Harsh or erratic automatic transmission shifting.
- ✔ A noticeable drop in fuel economy.
- ✔ The vehicle cranks but refuses to start (no-start condition).
- ✔ Communication errors with diagnostic scan tools.
Why Choose Our Pre-Programmed 2006 Envoy PCM?
Getting your Envoy back on the road shouldn’t be a complicated ordeal. This module is designed to be a direct, effective replacement for your original, faulty unit. By providing us with your vehicle’s VIN during checkout, you receive a module that is ready for installation right out of the box. This process eliminates the need for expensive trips to the dealership for programming. This specific module, part number 12591647, also serves as a direct replacement for a wide range of other GM part numbers, ensuring broad compatibility across models like the Trailblazer, Rainier, Hummer H3, and more. Please verify your part number or consult our fitment list to ensure this is the correct component for your vehicle.
Installation is typically straightforward for those with moderate mechanical skill. The module is located in the engine bay, and after disconnecting the battery, it’s a matter of unplugging the electrical connectors and unbolting the old unit. Once the new one is in place, a security relearn or CASE relearn procedure may be required, which can often be done without special tools. This simple process restores the complex systems your original PCM once managed, bringing your vehicle back to its factory-specified operation.
Frequently Asked Questions
What is a PCM and what does it do?
The Powertrain Control Module (PCM), often called the Engine Control Module (ECM), is your vehicle’s main computer. It controls and monitors the engine, transmission, and other critical systems to ensure optimal performance, fuel efficiency, and emissions.
Is this part truly ‘plug and play’?
Because we program the module to your vehicle’s specific VIN, it is as close to ‘plug and play’ as possible. In many cases, no further action is needed. However, some GM vehicles may require a simple, key-on/key-off security relearn procedure to sync the new PCM with your vehicle’s anti-theft system. This procedure is detailed in many online resources and does not require a dealer visit.
What information do I need to provide?
All we need is your vehicle’s 17-digit Vehicle Identification Number (VIN). You can typically find this on your driver-side dashboard (visible through the windshield), on the driver-side door jamb sticker, or on your vehicle’s registration and insurance documents.
Will this fix my check engine light?
If the check engine light is on due to a fault within the PCM itself, this replacement module will solve the problem. However, if the light is caused by a separate faulty sensor or component (like an oxygen sensor or catalytic converter), that part will still need to be repaired.
Does this module replace other part numbers?
Yes. This module is a compatible replacement for a wide range of part numbers listed in the description. It is a common hardware type used by GM across many vehicles, and our programming makes it specific to your application.