Is Your Cadillac STS Experiencing Frustrating Engine Problems?
If your 2009 or 2010 Cadillac STS is suffering from issues like a persistent Check Engine Light, rough idling, stalling, or a sudden drop in fuel economy, a failing Engine Control Module (ECM) is often the culprit. As the central computer for your engine, its proper function is critical for performance and reliability. Driving with a faulty ECM can lead to more significant engine damage and unpredictable behavior on the road.
A Technician’s Real-World Experience
“A customer’s 2009 STS 4.6L came into the shop last month with a no-start condition that had two other shops stumped. They had replaced the fuel pump and crank sensor, but the issue persisted. After hooking up my diagnostic scanner, I noticed erratic data from multiple sensors simultaneously—a classic sign of a failing computer, not failing sensors. The ECM’s internal voltage regulator was failing, causing it to send bad commands throughout the system. We installed one of these VIN-programmed modules, and the car fired right up and has run perfectly ever since. It’s a fix I’ve performed hundreds of times on this GM platform.”
The Direct Solution: Programmed and Ready to Install
This isn’t just a replacement part; it’s a complete solution. We take a high-quality, tested ECM and professionally program it to your vehicle’s specific VIN. This crucial step ensures that the computer communicates flawlessly with your car’s engine, transmission, and anti-theft system, just like the original from the factory. You get a part that’s ready for installation right out of the box, saving you from a costly and time-consuming trip to the dealership for programming.
- ✔ VIN-Specific Programming: We flash the module with the latest GM-approved software for your exact vehicle.
- ✔ Resolves Common Failures: Effectively corrects issues like false sensor codes, poor acceleration, and harsh shifting.
- ✔ Plug-and-Play: No additional programming or dealer intervention is required for installation.
- ✔ Restores Factory Performance: Get your vehicle running smoothly and efficiently again.
- ✔ Wide Compatibility: A direct replacement for multiple service numbers, ensuring a perfect match.
Easy Installation Guide for Your 2009–2010 STS Engine Control Module
Replacing the ECM on your STS is a straightforward job that can be done with basic hand tools. On this model, the ECM is typically located on the left-hand (driver’s side) frame rail.
- Safety First: Disconnect the negative terminal from your vehicle’s battery and wait at least 10 minutes to allow all systems to power down.
- Locate the ECM: Find the module on the driver’s side frame rail, inside the engine bay.
- Disconnect the Connectors: Carefully unlatch and remove the electrical wiring harness connectors from the old ECM. Inspect them for any signs of dirt or corrosion.
- Remove the Old Module: Unbolt the mounting hardware that secures the old ECM to its bracket and remove it from the vehicle.
- Install the New Module: Mount your new, pre-programmed ECM in place and secure it with the original hardware.
- Reconnect Everything: Firmly plug the wiring harness connectors into the new module until they click into place. Reconnect the negative battery terminal.
- Final Step: Start the vehicle. It may take a moment to idle smoothly as it syncs. Your Cadillac is ready to drive!
Expert Pro Tip: Connector Health is Key
Before plugging in your new ECM, take a moment to spray the vehicle’s harness connectors with a quality electronics cleaner. Use a small, soft brush (like a toothbrush) to gently scrub away any grime or light corrosion from the pins and sockets. A clean, solid connection is vital for the new module’s performance and longevity and prevents damage from a poor electrical contact.
Guaranteed Fitment and Interchangeability
This module is a direct replacement for several original GM service numbers, guaranteeing compatibility. Please provide your VIN at checkout for programming.
Replaces Part Numbers: 12636659, 12639300, 1263605, 12628993, 12628911, 12625453, 12622175, 12630464, 12678512
This ECM is also compatible with the following vehicles:
- Cadillac CTS: 2009 (6.2L)
- Cadillac DTS: 2009-2011
- Cadillac SRX: 2009 (4.6L)
- Cadillac STS: 2009 (4.4L, 4.6L), 2010 (4.6L)
- Cadillac XLR: 2009
- Chevrolet Colorado: 2009-2012 (2.9L, 3.7L)
- Chevrolet Corvette: 2009 (ZR1)
- Chevrolet Trailblazer: 2009 (6.0L)
- GMC Canyon: 2009-2012 (2.9L, 3.7L)
- GMC Envoy: 2009 (5.3L)
- Hummer H3: 2009-2010 (3.7L)
- Buick Lucerne: 2009-2011 (4.6L)
- Saab 9-7X: 2009