Restore Peak Performance to Your GM Vehicle
Is your Trailblazer, Envoy, or other GM vehicle suffering from frustrating issues like stalling, erratic idling, a persistent Check Engine Light, or a complete no-start condition? A failing Engine Control Module (ECM) is often the culprit, acting as the brain of your engine and controlling everything from fuel mixture to ignition timing. When it falters, the entire system can become unreliable. This replacement ECM, part number 12639300, is the definitive solution to get your vehicle running smoothly and dependably again.
The biggest challenge with replacing an ECM has always been the expensive and inconvenient programming required at a dealership. We eliminate that step entirely. By providing us with your vehicle’s VIN at checkout, our technicians will program this module with the very latest GM-certified software specific to your vehicle. This ensures all factory performance parameters are restored and that the module communicates flawlessly with your vehicle’s other systems right out of the box.
Case Study: A Tricky Diagnosis
I remember a 2009 Trailblazer SS with the 6.0L that came into my bay with a complaint of intermittent stalling at stoplights and a weird, random misfire that never seemed to set a consistent code. The owner had already replaced plugs, wires, and a coil pack with no success. After hooking up my scan tool and monitoring live data, I noticed the fuel trim commands would occasionally spike just before a stall. There were no external sensor faults. This pointed me toward an internal processing error in the computer. We installed a VIN-programmed ECM, and the problem was solved instantly. It’s a classic example of how a failing 2009 Trailblazer Engine Module can mimic other component failures, making a direct replacement the only true fix.
Is Your GM Vehicle Showing These Symptoms?
- ✔ Persistent Check Engine Light (CEL) that won’t clear.
- ✔ Diagnostic Trouble Codes (DTCs) related to internal module failure, such as P0601, P0606, or U0100 (Lost Communication with ECM/PCM).
- ✔ Unexplained drop in fuel economy.
- ✔ Engine stalling, stumbling, or hesitating during acceleration.
- ✔ Complete no-start condition where the engine cranks but won’t fire up.
- ✔ Harsh or erratic transmission shifting.
- ✔ Failure to pass state emissions testing due to readiness monitor issues.
A Straightforward Guide to Installation
Installing your new 2009 Trailblazer Engine Module is a job most DIYers can handle in their own driveway. Our VIN programming service makes it a direct-fit replacement without the need for a trip to the dealer.
- Safety First: Disconnect the negative terminal from your vehicle’s battery and secure it away from the post to prevent accidental reconnection.
- Locate the ECM: On the 2009 Trailblazer, the ECM is typically located on the driver’s side of the engine compartment, near the firewall. Consult your vehicle’s service manual for the exact location on other models.
- Disconnect and Remove: Carefully unplug the electrical connectors. There are usually locking tabs that need to be released. Once disconnected, unbolt the old module from its mounting bracket.
- Install the New Module: Bolt the new, pre-programmed ECM into place. Firmly reconnect the electrical harnesses, ensuring they click and lock securely.
- Reconnect Power: Reattach the negative battery terminal and tighten it.
- Perform Security Relearn: Most GM vehicles require a security relearn procedure to sync the new ECM with the anti-theft system. This typically involves turning the key to the ‘ON’ position for 10-15 minutes, then ‘OFF’ for 10 seconds, and repeating this cycle three times. Your vehicle will then start normally.
Verified Vehicle Compatibility
This module is a direct replacement for a wide range of GM vehicles. Please verify your model and engine options below. This unit is interchangeable with service numbers: 12636659, 12639300, 1263605, 12628993, 12628911, 12625453, 12622175, 12630464, and 12678512.
LUCERNE 09-11 (4.6L, lower part of air cleaner box)
Cadillac:
CTS 09 (6.2L, RH front engine compartment)
DTS 09-11
SRX 09 (4.6L, LH engine compartment)
STS 09 (4.4L or 4.6L, LH frame rail)
STS 10 (4.6L, LH frame rail)
XLR 09 (RH front engine compartment, ID 12636659 or 12625453)
Chevrolet:
COLORADO 09 (All Engines, RH firewall)
COLORADO 10-12 (2.9L or 3.7L, RH firewall)
CORVETTE 09 (ZR1, RH engine compartment)
TRAILBLAZER 09 (6.0L, LH engine)
GMC:
CANYON 09 (All Engines, RH firewall)
CANYON 10-12 (2.9L or 3.7L, RH firewall)
ENVOY 09 (5.3L, LH engine)
Hummer:
HUMMER H3 09-10 (All Engines, RH firewall)
Saab:
SAAB 9-7X 09 (LH engine)
Frequently Asked Questions
Do I need to do anything after installing this ECM?
Yes. While we handle the main programming, you must perform a security relearn procedure (also known as a key relearn or anti-theft relearn) after installation. This simple process syncs the new module to your vehicle’s keys and typically takes about 30 minutes with no special tools required.
What is VIN programming?
VIN programming means we load the specific software and calibrations from GM that match your vehicle’s unique Vehicle Identification Number. This ensures correct engine and transmission operation, proper emissions compliance, and compatibility with options like cruise control and four-wheel drive.
Is this a brand new part?
This is a high-quality, tested, and verified original equipment part that has been inspected and programmed with the latest software. It’s guaranteed to restore your vehicle’s factory functionality.
Will this fix my check engine light?
If the check engine light is caused by an internal ECM failure (like codes P0601-P0606), then yes, this will resolve the issue. However, if the light is on due to a faulty sensor (like an O2 sensor or MAP sensor), that part will still need to be replaced separately.
How do I provide my VIN?
Simply enter your 17-digit VIN in the designated box during the checkout process. Please double-check it for accuracy, as the programming is based entirely on this number.