Restore Peak Performance to Your 2006 Buick Rainier
Is your 2006 Buick Rainier, Trailblazer, or other compatible GM vehicle suffering from perplexing issues like a persistent check engine light, erratic shifting, poor fuel economy, or a no-start condition? These are classic signs of a failing Powertrain Control Module (PCM). The PCM is the central computer of your vehicle, responsible for managing the engine, transmission, and dozens of other critical systems. When it falters, the entire vehicle’s performance and reliability are compromised. This isn’t just an inconvenience; it can affect safety and lead to more costly repairs if left unaddressed.
This replacement Powertrain Control Module, part number 12591648, is the definitive solution to get your vehicle back on the road and running like new. We take the guesswork and hassle out of the replacement process. Unlike a generic module from a parts store, each unit we ship is meticulously programmed with the latest official GM software updates, tailored specifically to your vehicle’s Vehicle Identification Number (VIN). This ensures seamless communication between all vehicle systems and restores the original factory performance and efficiency specifications.
From the Diagnostic Bay
We had a 2006 Trailblazer EXT with the 4.2L engine come into the shop with a bizarre set of symptoms the owner had been chasing for months. It would randomly stall at stop lights, the transmission would sometimes refuse to shift out of second gear, and the check engine light would flash with a random misfire code (P0300) that no amount of new spark plugs or ignition coils could fix. After hours of checking wiring harnesses and sensors, we hooked up our high-level scan tool and monitored the PCM’s live data. We noticed the injector pulse width and ignition timing commands were fluctuating wildly for no reason. We suspected the PCM’s internal processor was failing. We installed one of our VIN-programmed modules, performed the security relearn, and the truck immediately ran perfectly. It was a classic case of a failing computer causing phantom mechanical symptoms.
Why Choose Our Pre-Programmed 2006 Rainier PCM?
Replacing a PCM isn’t as simple as swapping out a battery. The module contains vital security information (related to the anti-theft system) and operational parameters that are unique to your vehicle’s specific configuration. Our service eliminates the need for an expensive trip to the dealership for programming. By providing your VIN during checkout, you receive a module that is ready for installation. For many vehicles on this platform, the process is straightforward, though a security relearn procedure and a crankshaft position variation relearn (CASE learn) may be required after installation. These procedures can often be done without a specialized scan tool.
Common Symptoms of a Failing PCM
- ✔ Persistent Check Engine Light (CEL) with various trouble codes.
- ✔ Rough or unstable idling.
- ✔ Noticeable decrease in fuel efficiency.
- ✔ Harsh or erratic automatic transmission shifting.
- ✔ Engine stalling, stumbling, or hesitating during acceleration.
- ✔ Complete no-start or intermittent starting problems.
- ✔ Failure to pass state emissions testing.
- ✔ Communication errors with diagnostic scan tools.
Guaranteed Fitment & Compatibility
This module is a direct replacement for a wide range of GM trucks and SUVs, ensuring broad compatibility. It replaces numerous original part numbers, including: 12569773, 12588650, 12589311, 12589585, 12591647, 12593531, 12593532, 12594430, 12594431, 12596783, 12596784, 12597521, 12597776, 12597777, 12600818, 12604438, 12604439, 12606369, 12606373, 12606374, 12606398, 12606399, 19209820, and 19209821. Please verify your part number or consult the fitment list below to confirm this is the correct part for your vehicle.
This module is confirmed to fit:
- 2006 Buick Rainier (4.2L)
- 2006 GMC Envoy / Envoy XL (4.2L)
- 2006 Chevrolet Trailblazer / Trailblazer EXT (4.2L)
- 2004-2006 Chevrolet Colorado
- 2004-2006 GMC Canyon
- 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
Do I need to do any programming after I receive this PCM?
We handle the main programming for you by flashing the module with the latest GM calibration for your specific VIN. However, upon installation, you will need to perform a Security Relearn procedure (also known as a Passlock or VATS relearn). This syncs the new module with your vehicle’s anti-theft system and keys. This procedure typically takes about 30 minutes and can be done without special tools. A Crankshaft Position Variation (CASE) relearn may also be required to prevent a P1336 trouble code, which does require a capable bidirectional scan tool.
Where do I provide my vehicle’s VIN?
Please enter your 17-digit VIN in the notes section during checkout or send it to us in a message after you complete your purchase. We cannot program and ship your module without your VIN.
Is this a brand new part?
This is a genuine OEM component that has been thoroughly inspected, tested, and prepared to ensure it meets or exceeds original factory specifications. It is loaded with fresh, vehicle-specific software to provide reliable, long-lasting service.
What if my original part number is not on your list?
The part numbers listed are the most common ones this module replaces. If your number is different, please contact us with your VIN and original part number. We can verify compatibility for you to ensure you receive the correct part.
What is the security relearn procedure?
The standard GM security relearn involves turning the key to the ‘ON’ position for 10 minutes, then ‘OFF’ for 10 seconds, and repeating this cycle three times. On the final cycle, the vehicle should start. Instructions for this process are widely available online for your specific model and are relatively simple for most owners to perform.