Restore Peak Performance to Your GM Vehicle
Is your Trailblazer, Corvette, or Hummer suffering from frustrating and hard-to-diagnose issues? An erratic idle, poor fuel economy, a persistent Check Engine Light, or even a no-start condition can often be traced back to a single component: a failing Engine Control Module (ECM). As the brain of your vehicle’s engine, the ECM is responsible for managing everything from fuel injection and ignition timing to emissions controls. When it falters, the entire system’s performance and reliability are compromised.
This replacement ECM, part number 12628911, is the definitive solution. We take the guesswork and hassle out of the repair process. Before this module ever ships, our technicians will program it with the latest GM-certified software, specifically matched to your vehicle’s unique Vehicle Identification Number (VIN). This means no expensive trips to the dealership for programming. You receive a part that is truly ready for installation right out of the box, getting you back on the road faster.
From the Diagnostic Bay: The Ghost in the Machine
I once had a 2009 Trailblazer SS with the 6.0L in my shop that was driving its owner crazy. It would run perfectly for days, then suddenly stall at a red light or refuse to start after being parked. The owner had already replaced the battery and alternator. Scans showed a mix of intermittent communication codes (U-codes) and a generic processor fault (P0606), but they’d clear and not return for a week. After confirming solid power and ground connections to the ECM, I knew where the problem was. The internal circuitry of the original ECM was failing under certain temperature conditions. Swapping in a properly programmed module like this one solved the problem permanently. These ‘ghost’ issues are a classic sign of a failing 2009 Trailblazer Engine Control Module.
Is Your Vehicle Showing These ECM Failure Signs?
- âś” Check Engine Light is on with codes like P0601 (Internal Control Module Memory Check Sum Error) or P0606 (ECM/PCM Processor Fault).
- âś” The engine cranks but refuses to start.
- âś” Unexplained drops in fuel efficiency.
- âś” Noticeable loss of power or hesitation during acceleration.
- âś” Rough or inconsistent idling.
- âś” Automatic transmission shifts harshly or at the wrong times.
- âś” Communication errors with diagnostic scan tools.
A Straightforward Guide to Installation
Installing your new 2009 Trailblazer Engine Control Module is a manageable job for a DIYer with basic tools. Always consult a vehicle-specific repair manual, but here are the general steps:
- Safety First: Disconnect the negative terminal from your vehicle’s battery to prevent any electrical shorts.
- Locate the ECM: On most vehicles in the fitment list, the ECM is found in the engine bay, often on the firewall or near the air filter box. For the 2009 Trailblazer, it’s typically on the driver’s side of the engine.
- Disconnect Connectors: Carefully release the locking tabs and unplug the large wiring harness connectors from the old ECM. Inspect them for any corrosion or damage.
- Remove the Old Module: Unbolt the old ECM from its mounting bracket.
- Install the New Module: Bolt your new, pre-programmed ECM into place.
- Reconnect Everything: Firmly plug the wiring harnesses back into the new module until they click, and then reconnect the negative battery terminal.
- Security Relearn (If Necessary): In some cases, a security or anti-theft relearn procedure may be required. This can typically be done without special tools by cycling the ignition key and is outlined in many online resources.
Verified Vehicle Compatibility List
This ECM is a direct replacement for multiple service numbers, including 12636659, 12639300, 1263605, 12628993, 12628911, 12625453, 12622175, 12630464, and 12678512. It is guaranteed to fit the following models:
- CADILLAC CTS (2009) 6.2L
- CADILLAC DTS (2009-2011)
- CADILLAC SRX (2009) 4.6L
- CADILLAC STS (2009) 4.4L, 4.6L
- CADILLAC STS (2010) 4.6L
- CADILLAC XLR (2009)
- CHEVROLET COLORADO (2009)
- CHEVROLET COLORADO (2010-2012) 2.9L, 3.7L
- CHEVROLET CORVETTE (2009) ZR1
- CHEVROLET TRAILBLAZER (2009) 6.0L
- GMC CANYON (2009)
- GMC CANYON (2010-2012) 2.9L, 3.7L
- GMC ENVOY (2009) 5.3L
- HUMMER H3 (2009-2010)
- HUMMER H3T (2009-2010)
- BUICK LUCERNE (2009-2011) 4.6L
- SAAB 9-7X (2009)
Choosing this pre-programmed 2009 Trailblazer Engine Control Module is the smartest way to solve complex engine problems, restore factory performance, and ensure your vehicle runs reliably for years to come. Provide your VIN at checkout and let us handle the rest.
Frequently Asked Questions
Do I need to do any programming myself?
No. This ECM comes fully programmed to your vehicle’s VIN with the latest GM software updates. It is ready to be installed upon arrival. A simple security relearn procedure may be needed, which doesn’t require special tools.
How do I provide my VIN?
You can enter your 17-digit Vehicle Identification Number (VIN) during the checkout process. Please double-check it for accuracy, as the programming is specific to this number.
Will this fix my car’s specific problem?
This module corrects issues directly caused by a faulty ECM, such as certain no-start conditions, erratic behavior, and specific diagnostic trouble codes (DTCs). While it’s a common failure point, always ensure a proper diagnosis has been performed to confirm the ECM is the root cause of your problem.
Is this part difficult to install?
For someone with basic mechanical skills, the installation is straightforward. It involves disconnecting the battery, unplugging the old module, unbolting it, and then installing the new one. The most important part is ensuring the wiring harness connectors are seated securely.
What if I have a different part number on my old ECM?
This module is a direct replacement for several GM service numbers, including 12636659, 12628993, 12625453, and others listed in the description. As long as your vehicle is on the compatibility list, this part will function correctly.