Restore Your Truck’s Performance and Reliability
Is your 2004-2006 Chevrolet Colorado, GMC Canyon, or Hummer H3 suffering from perplexing issues like stalling, erratic shifting, a persistent check engine light, or a complete no-start condition? These are common indicators of a failing Powertrain Control Module (PCM), the central computer responsible for managing your vehicle’s engine and transmission. A faulty PCM can disrupt everything from fuel delivery and ignition timing to transmission shift points, leaving you with an unreliable and frustrating vehicle. This replacement PCM, part number 12596783, is the definitive solution to restore your truck’s original performance and dependability.
The Brain of Your Operation: What Does the PCM Do?
Think of the PCM as the command center for your vehicle’s powertrain. It constantly analyzes data from dozens of sensors—like the crankshaft position sensor, oxygen sensors, and throttle position sensor—to make real-time adjustments. It controls the fuel injectors, spark plugs, and transmission solenoids to ensure optimal power, fuel efficiency, and low emissions. When this critical component begins to fail, the symptoms can be widespread and difficult to diagnose, often mimicking other part failures. By replacing a faulty module, you restore the precise calculations needed for your engine and transmission to work in harmony.
Expert Pro Tip
Before condemning your PCM, always perform a thorough check of all power and ground connections to the module. On these GM trucks, a corroded ground wire or a loose connection at the fuse box can cause symptoms identical to a failed PCM. Use a multimeter to verify you have stable battery voltage and a clean ground path at the PCM connectors. This simple diagnostic step can save you time and money.
Common Symptoms of a Failing GM PCM
- ✔ Check Engine Light: Often with communication error codes (U-codes) or internal processor fault codes (P0600-P0606).
- ✔ No-Start Condition: The engine cranks but will not start, often due to a lack of fuel injector or ignition coil command from the PCM.
- ✔ Poor Engine Performance: Stalling, hesitation, rough idling, and a noticeable loss of power can all point to a faulty computer.
- ✔ Erratic Transmission Shifting: Harsh shifts, delayed engagement, or getting stuck in one gear can be caused by the PCM failing to properly control the transmission.
- ✔ Reduced Fuel Economy: An inefficient engine burn due to incorrect PCM calculations will lead to more frequent stops at the gas station.
- ✔ Failure to Pass Emissions Test: The PCM controls the vehicle’s emissions systems, and a failure will prevent monitors from running correctly.
Installation and Setup for Your 2004-2006 Colorado PCM
This PCM is a direct-fit replacement, but installation requires a critical final step. Physically, the module is located on the right-hand (passenger side) firewall in the engine bay. After disconnecting the battery, you can unbolt the old module and swap the connectors to the new one. However, your vehicle will not start until you perform the GM PASSLOCK II Security Relearn Procedure. This procedure pairs the new PCM with your vehicle’s anti-theft system. It’s a simple process that does not require special tools and typically involves a sequence of turning the key on and off. We include instructions to guide you through this essential step, ensuring a successful installation.
Guaranteed Compatibility and VIN Programming
This isn’t just an off-the-shelf part. To ensure a seamless installation, we program the module specifically for your truck using the Vehicle Identification Number (VIN) you provide. This process loads the correct factory software and calibrations for your engine, transmission, and specific options. It also receives the latest software updates from GM, which can resolve common factory drivability issues. This is a crucial service that makes this a true plug-and-play solution (after the security relearn). This 2004-2006 Colorado PCM is a direct replacement for a wide range of part numbers and fits multiple vehicles.
This module is a direct replacement for the following 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.
This part will fit these makes and models with these options:
- CHEVROLET COLORADO 04-06 (RH firewall)
- GMC CANYON 04-06 (RH firewall)
- HUMMER H3 06 (RH firewall)
- ISUZU I-280 06 (RH firewall)
- ISUZU I-350 06 (RH firewall)
- BUICK RAINIER 06 (LH engine), 4.2L
- CHEVROLET TRAILBLAZER 06 (LH engine), 4.2L
- CHEVROLET TRAILBLAZER EXT 06 (LH engine), 4.2L
- GMC ENVOY 06 (LH engine), 4.2L
- GMC ENVOY XL 06 (LH engine), 4.2L
- ISUZU ASCENDER 06 (LH engine), 4.2L
- SAAB 9-7X 06 (LH engine), 6 cylinder
Frequently Asked Questions
Do I need to do anything after installing this PCM?
Yes. While we program the module to your VIN, you MUST perform the GM PASSLOCK Security Relearn Procedure after installation. This pairs the new computer to your vehicle’s anti-theft system. The truck will not start until this is completed. We provide clear instructions for this simple, tool-free process.
How do I provide my VIN number?
After you complete your purchase, you will receive instructions on how to send us your vehicle’s 17-digit VIN. We cannot ship your part until we receive this information, as the programming is specific to your truck.
Is this a brand new part?
This is a high-quality, fully tested OEM replacement part that has been serviced and verified to meet or exceed original factory specifications. It is programmed with the latest GM software for your vehicle.
Will this fix my transmission shifting problems?
In many cases, yes. The PCM is responsible for controlling the transmission solenoids and interpreting sensor data to determine shift points. If the PCM is the root cause of your shifting issues, this part will resolve them. However, transmission problems can also be caused by mechanical failures, bad solenoids, or low fluid, so a complete diagnosis is always recommended.
What if my part number is not on your list?
The part numbers listed are the most common ones this module replaces. If your original module’s part number is not listed, please contact us with your VIN. We can verify compatibility and ensure you receive the correct computer for your vehicle.