Is Your 2006 GMC Envoy Running Erratically? The PCM is a Likely Culprit.
If your 2006 GMC Envoy is experiencing frustrating issues like stalling, poor fuel economy, a persistent check engine light, or erratic shifting, the problem may lie with its most critical component: the Powertrain Control Module (PCM). As the central computer, the PCM orchestrates everything from fuel injection and ignition timing to transmission shifting and emissions control. When it begins to fail, it can create a cascade of problems that are often difficult to diagnose, leaving you stranded and facing expensive repair bills.
A failing PCM doesn’t just impact performance; it can prevent your vehicle from starting altogether or cause it to fail an emissions test. Don’t let a faulty computer dictate your vehicle’s reliability. This replacement module is the definitive solution to restore your Envoy’s factory performance and get you back on the road with confidence.
From the Diagnostic Bay
We once had a 2006 Trailblazer with the 4.2L engine (the same platform as the Envoy) come into the shop with a complaint of a severe, harsh shift from first to second gear. The owner had already spent a small fortune at another shop replacing transmission solenoids and fluid, with no improvement. Our diagnostics showed no specific transmission codes, but we did find intermittent U-codes (communication loss) when scanning the entire network. This pointed us away from the transmission and toward the network controller—the PCM. After installing a correctly programmed PCM, the harsh shifting vanished completely. It was a classic case of the vehicle’s brain sending bad signals to an otherwise healthy component.
Common Symptoms of a Failing PCM
- ✔ Check Engine Light: The light is on, often with communication-related codes (like U0100) or internal processor failure codes (like P0601 or P0606).
- ✔ Poor Engine Performance: You may experience rough idling, engine misfires, hesitation during acceleration, or a noticeable decrease in power.
- ✔ Reduced Fuel Economy: A faulty PCM can’t efficiently manage the engine’s fuel delivery, leading to more trips to the gas station.
- ✔ Erratic Transmission Shifting: The PCM controls shift points. Failure can cause hard shifts, delayed shifting, or getting stuck in one gear.
- ✔ No-Start Condition: The engine may crank but refuse to start because the PCM isn’t commanding the fuel injectors or ignition coils to fire.
- ✔ Failure to Pass Emissions: An improperly functioning PCM cannot manage the emissions systems correctly, leading to a failed smog test.
Why Choose Our Programmed 2006 Envoy PCM?
This isn’t just a generic, off-the-shelf part. It is a complete, vehicle-specific solution. We take your vehicle’s unique 17-digit Vehicle Identification Number (VIN) and program the module with the latest, most stable software updates directly from GM. This critical step ensures that the computer communicates flawlessly with all other modules in your 2006 Envoy PCM system, just as it did from the factory. This process corrects software bugs from the original release and optimizes performance and longevity. By ordering from us, you bypass the expensive programming fees and scheduling hassles at a dealership.
Simple Process, Lasting Solution
Getting your Envoy back in top shape is straightforward:
- Place Your Order: Add this module to your cart and complete the checkout process.
- Provide Your VIN: After your purchase, you will need to send us your vehicle’s VIN. This is mandatory for the programming service.
- We Program & Ship: Our technicians will flash the module with your vehicle’s specific software and ship it directly to you.
- Install & Relearn: Once you receive the part, simply disconnect your battery, swap the old module with the new one, and reconnect the battery. You will likely need to perform a simple security relearn procedure, which can typically be done in your driveway without any special tools.
Guaranteed Fitment for Your Vehicle
This module is a direct replacement for a wide range of GM trucks and SUVs. Please verify that your vehicle and original part number are listed below.
Replaces 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
Fits The Following Models:
- 2006 Buick Rainier (4.2L)
- 2004-2006 Chevrolet Colorado
- 2006 Chevrolet Trailblazer & Trailblazer EXT (4.2L)
- 2004-2006 GMC Canyon
- 2006 GMC Envoy & Envoy XL (4.2L)
- 2006 Hummer H3
- 2006 Isuzu Ascender (4.2L)
- 2006 Isuzu i-280
- 2006 Isuzu i-350
- 2006 Saab 9-7x (6-cylinder)
Frequently Asked Questions
What exactly does the PCM do on my 2006 Envoy?
The Powertrain Control Module (PCM) is the main computer that controls all aspects of your engine and transmission. It reads data from dozens of sensors—like oxygen sensors, crank/cam sensors, and throttle position—and uses that information to make real-time adjustments to fuel delivery, spark timing, and transmission shift points for optimal performance, fuel economy, and emissions.
Why do you need my VIN?
Your Vehicle Identification Number (VIN) contains critical information about your vehicle’s specific build, including engine type, transmission, emissions systems, and other options. Programming the PCM with your VIN ensures it has the exact software and calibrations required for your vehicle to function correctly. A generic or non-programmed module will not work.
Where is the PCM located on a 2006 GMC Envoy?
On the 2006 GMC Envoy with the 4.2L engine, the PCM is typically located in the engine compartment on the driver’s side (LH side), near the firewall or inner fender.
Is this a difficult part to install myself?
The physical replacement is straightforward for someone with basic mechanical skills. It involves disconnecting the battery and then unplugging the electrical connectors and unbolting the module. The most important post-installation step is the security relearn (also called Passlock relearn), which pairs the new PCM to your vehicle’s anti-theft system. This procedure typically involves turning the key to the ‘ON’ position for 10 minutes, then ‘OFF’ for 10 seconds, and repeating this cycle three times. Instructions can be readily found online for your specific model.
Will this fix my check engine light?
If the check engine light is caused by an internal failure of the original PCM (common codes include P0601-P0606) or a PCM-related communication error, then this replacement module will solve the problem. However, if the light is on due to a faulty sensor or another component, you will still need to diagnose and repair that separate issue.