Restore Peak Performance and Reliability to Your Vehicle
Is your Cadillac STS, Corvette, or other GM vehicle suffering from frustrating issues like intermittent stalling, a persistent check engine light, poor fuel economy, or a complete no-start condition? These are classic signs of a failing Engine Control Module (ECM), the central computer that manages your engine’s performance. When the ECM begins to fail, it can cause a cascade of confusing problems that are often difficult to diagnose. This replacement 2009-2010 STS Engine Control Module is the definitive solution to restore your vehicle’s factory operation and your peace of mind.
Unlike a standard replacement part that requires a costly trip to the dealership for programming, this module arrives at your door ready for installation. We take your Vehicle Identification Number (VIN) at the time of purchase and professionally flash the unit with the latest, most stable software updates directly from GM. This ensures perfect compatibility and communication with your vehicle’s other systems, eliminating the guesswork and extra expense. It’s a direct-fit, reliable solution for both professional technicians and savvy DIYers.
From the Diagnostic Bay: The Ghost in the Machine
A 2009 Cadillac CTS-V came into my shop with a complaint that baffled two other mechanics. The owner described random power loss, occasional transmission shifting issues, and a check engine light that would come and go. We pulled codes and found a mix of communication errors (U-codes) and a random misfire code. Instead of chasing individual sensors, my experience pointed to the central hub: the ECM. The internal processor was failing, sending corrupt data across the vehicle’s network. We replaced it with a VIN-programmed module like this one. The installation was simple, and upon startup, all the ghost-like issues were gone. The car ran smoother than it had in years, proving that a solid 2009-2010 STS Engine Control Module is the foundation of a healthy vehicle.
Common Signs of a Failing Engine Control Module
- ✔ Check Engine Light is illuminated or flashing
- ✔ Vehicle will not start or is very difficult to start
- ✔ Stalling or rough idling for no apparent reason
- ✔ Noticeable decrease in fuel efficiency
- ✔ Poor engine performance, hesitation, or misfires
- ✔ Automatic transmission shifting problems
- ✔ Associated Diagnostic Trouble Codes (DTCs) like P0601, P0606, or U0100
A Straightforward Guide to Installation
- ✔ Safety First: Always disconnect the negative terminal from your vehicle’s battery before beginning any electrical work.
- ✔ Locate the ECM: On the 2009-2010 STS, the ECM is typically located on the left-hand frame rail. For other models, refer to the fitment list for its general location (e.g., RH firewall, LH engine compartment).
- ✔ Disconnect Connectors: Carefully unclip the wiring harness connectors from the old module. Be gentle, as these plastic clips can become brittle over time.
- ✔ Remove the Old Module: Unbolt the old ECM from its mounting bracket. Keep the hardware, as you may need to reuse it.
- ✔ Install the New Module: Mount your new, pre-programmed ECM in place and securely fasten it.
- ✔ Reconnect Everything: Plug the wiring harnesses back into the new module until they click securely. Reconnect the negative battery terminal.
- ✔ Final Check: Start the vehicle. The check engine light should be off, and the engine should run smoothly. In some cases, a security or crank relearn procedure may be necessary, which can often be done without special tools.
Verified Vehicle Compatibility
This module is a direct replacement for service number 12625453 and is interchangeable with 12636659, 12639300, 1263605, 12628993, 12628911, 12622175, 12630464, and 12678512. It is guaranteed to fit the following vehicles:
CADILLAC DTS 09-11
CADILLAC SRX 09 (LH engine compartment), (4.6L)
CADILLAC STS 09 (LH frame rail), 4.4L or 4.6L
CADILLAC STS 10 (LH frame rail), (4.6L)
CADILLAC XLR 09 (RH front engine compartment), ID 12625453 or 12636659
CHEVROLET COLORADO 09 (RH firewall)
CHEVROLET COLORADO 10-12 (RH firewall), 2.9L or 3.7L
CHEVROLET CORVETTE 09 (RH engine compartment), ZR1
CHEVROLET TRAILBLAZER 09 (LH engine), 6.0L
BUICK LUCERNE 09-11 (lower part of air cleaner box), 4.6L
GMC CANYON 09 (RH firewall)
GMC CANYON 10-12 (RH firewall), 2.9L or 3.7L
GMC ENVOY 09 (LH engine), 5.3L
HUMMER H3 09-10 (RH firewall)
SAAB 9-7X 09 (LH engine)
Frequently Asked Questions
Do I need to do any programming myself?
Do I need to do any programming myself?
No. We handle all the programming for you before shipment. Simply provide your vehicle’s 17-digit VIN when you order, and we will flash the module with the latest GM software specific to your car. It arrives ready to install.
Is this a simple plug-and-play installation?
Yes, for most vehicles. Once you physically swap the module, the car should start and run correctly. Some vehicles may require a simple security relearn procedure, which typically involves turning the key on and off in a specific sequence. Instructions are widely available online or in service manuals.
How do I find my VIN?
Your VIN can be found on your vehicle’s registration, insurance card, or on the driver’s side of the dashboard, visible through the windshield.
Will this fix my specific check engine light codes?
This module is the direct solution for internal ECM failure codes like P0601 or communication codes like U0100. If your diagnostics point to a faulty computer, this part is designed to resolve those issues. It will not fix problems caused by other faulty sensors or mechanical parts.
What if my part number is slightly different?
This module is interchangeable with a wide range of GM service numbers, including 12636659, 12639300, and others listed in the description. As long as your part number is on our interchange list, this module will work for your vehicle once programmed to your VIN.