Programmed 2006 Rainier Powertrain Module 12597521 | VIN Matched

Restore Peak Performance to Your GM Truck or SUV

Is your 2006 Buick Rainier, Trailblazer, or Hummer H3 suddenly stalling, shifting erratically, or refusing to start? These frustrating and often intermittent issues frequently point to a failing Powertrain Control Module (PCM). As the brain of your vehicle, the PCM manages everything from fuel mixture and spark timing to transmission shift points. When it falters, your vehicle’s reliability and performance suffer dramatically. This isn’t just an inconvenience; it can be a serious safety concern.

This replacement powertrain module is the definitive solution. It arrives at your door fully programmed with the latest GM factory software, specifically matched to your vehicle using its unique VIN. This critical step eliminates the need for expensive dealership programming, saving you time and money. By providing a reliable, correctly calibrated computer, you can restore your vehicle’s original performance and get back on the road with confidence.

Is Your Vehicle Showing These Symptoms?

A failing PCM can manifest in various ways. If you’re experiencing any of the following, it’s a strong indicator that your engine computer needs replacement. Look out for Diagnostic Trouble Codes (DTCs) like P0601, P0606, or U0100.

• ✔ Engine stalling or cutting out randomly
• ✔ Complete no-start condition (engine cranks but won’t fire)
• ✔ Harsh or erratic automatic transmission shifting
• ✔ Drastic decrease in fuel economy
• ✔ Check Engine Light is on with internal module or communication codes
• ✔ Misfires or rough running that can’t be traced to plugs, coils, or injectors

A Straightforward Guide to Installation

Installing your new 2006 Rainier Powertrain Module is a manageable task for a confident DIYer or a quick job for any professional mechanic. The key is that the difficult programming work is already done.

1. Safety First: Always disconnect the negative terminal from your vehicle’s battery before starting any electrical work.
2. Locate the PCM: On models like the Rainier, Trailblazer, and Envoy with the 4.2L engine, the PCM is typically located on the driver’s side (LH) of the engine block. On models like the Colorado, Canyon, and Hummer H3, it’s usually found on the passenger’s side (RH) firewall.
3. Disconnect Connectors: Carefully release the locking tabs and unplug all electrical harness connectors from the old module. Inspect the connectors for any corrosion or damage.
4. Remove the Old Module: Unbolt the old PCM from its mounting bracket. Keep the hardware as you will need it for the new module.
5. Install the New Module: Mount your new, pre-programmed PCM onto the bracket and secure it. Reconnect all electrical harnesses, ensuring they click securely into place.
6. Reconnect Battery: Reattach the negative battery terminal.
7. Perform Security Relearn: You will likely need to perform a simple security relearn procedure (often called a Passlock or Passkey relearn). This typically involves turning the key to the ‘ON’ position for 10-15 minutes, then off, and repeating two more times. This allows your vehicle’s anti-theft system to recognize the new PCM.

Verified Vehicle Compatibility

This module is a direct replacement for part number 12597521 and is compatible with a wide range of other part numbers. It is guaranteed to fit the following vehicles:

• Buick Rainier: 2006 (4.2L, LH engine)
• Chevrolet Colorado: 2004-2006 (RH firewall)
• Chevrolet Trailblazer & Trailblazer EXT: 2006 (4.2L, LH engine)
• GMC Canyon: 2004-2006 (RH firewall)
• GMC Envoy & Envoy XL: 2006 (4.2L, LH engine)
• Hummer H3: 2006 (RH firewall)
• Isuzu Ascender: 2006 (4.2L, LH engine)
• Isuzu i-280: 2006 (RH firewall)
• Isuzu i-350: 2006 (RH firewall)
• Saab 9-7X: 2006 (6-Cylinder, LH engine)

Frequently Asked Questions