Restore Peak Performance to Your GM SUV or Truck
Is your 2006 GMC Envoy XL, Trailblazer, or other compatible GM vehicle running rough, shifting erratically, or showing a persistent Check Engine Light? You’re not just dealing with an annoyance; you’re facing a failure of the vehicle’s central command center: the Powertrain Control Module (PCM). As a technician with over two decades of experience under the hood, I’ve seen firsthand how a failing PCM can cause a cascade of frustrating and hard-to-diagnose issues. This isn’t just a part—it’s the brain of your engine and transmission, and when it falters, your vehicle’s reliability and efficiency suffer.
This replacement 2006 Envoy XL Powertrain Control Module is your direct-fit, hassle-free solution. We take the guesswork and extra cost out of the repair by pre-programming the module specifically for your vehicle using your VIN. This means it arrives at your door loaded with the latest GM factory software updates, ready for installation. You get to skip the expensive trip to the dealership for programming, saving you time and hundreds of dollars.
Case Study: A Tricky Diagnosis
I remember a 2006 Trailblazer that came into the shop with a complaint of intermittent stalling at stoplights and a random P0606 (PCM Processor Fault) code that would come and go. The owner had already replaced the spark plugs and a coil pack with no success. We spent hours checking grounds and wiring harnesses, which all looked perfect. On a hunch, we monitored the PCM’s internal temperature data on a long test drive. We noticed that right before a stall, the temperature reading would spike erratically. The culprit wasn’t a sensor or a wire; the PCM itself was failing internally under heat load. Swapping in a pre-programmed PCM like this one solved the problem instantly. It’s a classic example of how electronic components can fail in ways that mimic mechanical issues.
Common Signs of a Failing PCM
If you’re experiencing any of the following, a faulty engine computer could be the root cause. This module is the definitive fix for these common symptoms:
- ✔ Check Engine Light is on with codes like P0601, P0602, P0606, or other communication errors.
- ✔ Your vehicle fails to start or has a hard starting condition.
- ✔ Unexplained drop in fuel economy (MPG).
- ✔ Harsh or erratic automatic transmission shifting.
- ✔ Engine stalling, stumbling, or misfiring for no apparent reason.
- ✔ Communication loss with your scan tool.
A Straightforward Guide to Installation
Installing your new 2006 Envoy XL Powertrain Control Module is a manageable job for a confident DIYer. Follow these steps carefully for a smooth installation.
- Safety First: Always disconnect the negative terminal from your vehicle’s battery and wait at least 10 minutes to allow the system to fully discharge.
- Locate the Module: On most 4.2L models like the Envoy and Trailblazer, the PCM is located on the driver’s side of the engine block. On other models like the Colorado or H3, it may be on the RH firewall. Consult your service manual if you’re unsure.
- Disconnect Connectors: Carefully release the locking tabs on the electrical connectors and pull them straight out from the module. Never force them. Inspect the connectors for any corrosion or damage.
- Remove the Old PCM: Unbolt the module from its mounting bracket. There are typically two or three bolts holding it in place.
- Install the New PCM: Mount your new, pre-programmed module in place and tighten the bolts securely.
- Reconnect Everything: Plug the electrical connectors back into the new PCM until they click firmly into place. Reconnect your negative battery terminal.
- Perform Security Relearn: In many cases, you will need to perform a simple key-cycle security relearn procedure. This typically involves turning the key to the ‘ON’ position for 10-15 minutes. Instructions will be included with your part.
Will This Fit My Vehicle?
This module is a direct replacement for a wide range of GM vehicles and part numbers. Please verify your vehicle is on the list below. Upon purchase, we will ask for your VIN to ensure 100% correct programming.
- 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 & i-350: 2006
- Saab 9-7x: 2006 (6-cylinder)
This unit 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.
Frequently Asked Questions
Q: What exactly is a Powertrain Control Module (PCM)?
A: The PCM is your vehicle’s main computer. It controls all aspects of engine performance, fuel delivery, ignition timing, and automatic transmission shifting to ensure optimal power, efficiency, and emissions.
Q: Do I need to get this programmed at a dealer?
A: No! That’s the key benefit of our service. We program the module to your vehicle’s specific VIN before we ship it. It arrives ready to install, saving you a costly trip to the dealership.
Q: What happens if I don’t provide my VIN?
A: Providing your VIN is mandatory for this part. We cannot program or ship the module without it, as the software is unique to each vehicle. This ensures a perfect match and proper function.
Q: Where is the PCM located on my 2006 Envoy XL?
A: On the 2006 Envoy XL with the 4.2L engine, the PCM is typically mounted on the driver’s side of the engine block, below the intake manifold.
Q: Is any other work required after installation?
A: After installation, you will need to perform a simple security relearn procedure, also known as a Passlock or anti-theft relearn. This procedure is done with your ignition key and requires no special tools. We include easy-to-follow instructions.