Is your Trailblazer or Envoy running rough, hesitating, or throwing confusing check engine lights? A faulty engine computer can be the hidden culprit behind frustrating performance issues, turning your reliable SUV into a source of daily stress. This isn’t just an inconvenience; it’s a matter of confidence on the road. Restore that confidence with our expertly programmed Powertrain Control Module (PCM), the true brain of your vehicle’s engine. We take the guesswork out of the repair by flashing this unit with the latest official GM software, tailored specifically to your vehicle’s Vehicle Identification Number (VIN). This ensures a seamless, plug-and-drive installation that gets you back to enjoying a smooth, powerful, and efficient ride.
Warning Signs and How to Overcome Them
If you’re noticing any of these symptoms, your original PCM may be failing. Replacing it with our pre-programmed unit is the definitive solution to restore your vehicle’s health and your peace of mind.
- ✔ Persistent Check Engine Light (CEL) with codes like P0601, P0602, or P0606.
- ✔ Unexplained drops in fuel economy.
- ✔ Rough idling, stalling, or hesitation during acceleration.
- ✔ Harsh or erratic automatic transmission shifting.
- ✔ Complete no-start condition where the engine cranks but won’t fire up.
- ✔ Communication errors with diagnostic scan tools.
Guided Installation for a Confident Fix
You don’t need to be a master mechanic to complete this job. Follow these simple steps for a successful installation.
- Safety First: Disconnect the negative terminal from your vehicle’s battery and wait at least 10 minutes to ensure all systems are powered down.
- Locate the Module: On most 4.2L Trailblazer and Envoy models, the PCM is located on the driver’s side of the engine block.
- Disconnect Connectors: Carefully unclip the wiring harness connectors from the old PCM. They have locking tabs, so be gentle to avoid damage.
- Remove the Old Unit: Unbolt the old PCM from its mounting bracket and remove it from the vehicle.
- Install the New PCM: Mount your new, pre-programmed PCM onto the bracket and securely tighten the bolts.
- Reconnect and Secure: Plug the wiring harnesses back into the new module until they click firmly into place. Reconnect your vehicle’s battery.
- Final Steps: Your vehicle may require a security relearn procedure (often called a CASE relearn), which can be performed with a capable scan tool or by a local shop. This syncs the new computer with your vehicle’s anti-theft system.
Tailored Fit for Your Ride
This 2006 Trailblazer PCM is a direct-fit replacement for the following vehicles equipped with the 4.2L inline-6 or other specified engines. It replaces a wide range of original part numbers, ensuring broad compatibility.
- 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 a compatible replacement for 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
Do I need to do any programming myself?
No. We handle all the programming before we ship the module to you. It arrives flashed with the latest GM updates and matched to your vehicle’s VIN, making it ready for installation right out of the box.
Where do I provide my vehicle’s VIN?
After you complete your purchase, you will receive instructions on how to send us your 17-digit VIN. We cannot ship your order until we receive this information, as it is essential for correct programming.
Will this fix my specific problem?
This PCM is the correct solution for a wide range of engine performance issues, especially those related to internal module failure (e.g., DTC P0601). While it solves the most common electronic problems, ensure your vehicle’s mechanical and wiring systems are in good condition for a complete repair.
What is a security relearn or CASE relearn?
After installation, your vehicle’s anti-theft system and crankshaft position sensor need to be synchronized with the new PCM. This is a standard procedure called a security or CASE relearn, which can be completed by most automotive shops or with a high-end diagnostic scan tool. Your vehicle may not start or may run poorly until this is performed.
Is this a used part?
This is a professionally inspected and verified component. Each module undergoes rigorous testing to ensure it meets or exceeds original factory performance standards before being programmed and shipped.