Restore Your Cadillac’s Performance and Reliability
Is your 2009-2011 Cadillac DTS, or another compatible GM vehicle, suffering from frustrating and unpredictable engine problems? A faulty Engine Control Module (ECM) is often the culprit behind issues like a persistent check engine light, poor fuel economy, stalling, or a complete no-start condition. As the brain of your vehicle’s engine, a failing ECM can disrupt everything from fuel injection to transmission shifting. This replacement Engine Control Module, part number 12636659, is the definitive solution to get your vehicle running smoothly again.
What sets this module apart is our complimentary programming service. Before we ship your part, our experienced technicians will flash the module with the latest GM-approved software updates, specifically matched to your vehicle using your VIN. This means you receive a part that is truly plug-and-play, saving you a costly trip to the dealership and hundreds of dollars in programming fees. Simply provide your VIN during checkout, and we’ll handle the rest.
Common Signs of a Failing Engine Computer
- ✔ Check Engine Light is on with internal processor codes like P0601, P0602, or P0606.
- ✔ Vehicle refuses to start or starts intermittently for no apparent reason.
- ✔ Noticeable drop in fuel efficiency.
- ✔ Engine stalling, stumbling, or running rough.
- ✔ Automatic transmission shifting erratically or harshly.
- ✔ Loss of communication with the module (U-codes stored in other computers).
- ✔ Apparent failure of multiple sensors at once.
Case Study: A Tricky Diagnosis
I remember a 2010 Cadillac DTS that came into my shop. The owner had already replaced the fuel pump and crankshaft sensor at another garage, but it still had an intermittent no-start condition. No codes were stored. After checking all the basics—power, ground, and network communication to the ECM—we noticed that the 5-volt reference signal would occasionally drop out while cranking. This wasn’t a sensor issue; it was the ECM’s internal voltage regulator failing under load. We installed a VIN-programmed module just like this one, and the car fired up perfectly every time. It’s a classic example of how a failing ECM can create ghost-like symptoms that lead you down the wrong diagnostic path.
Why a Programmed 2009-2011 DTS ECM is the Smart Choice
Choosing a reliable replacement for your 2009-2011 DTS ECM is critical for your vehicle’s longevity and performance. This module is tested for full functionality and programmed to your specific vehicle, ensuring all systems operate exactly as the manufacturer intended. It restores factory performance, optimizes fuel delivery, and ensures emissions systems are functioning correctly. Don’t settle for a generic, unprogrammed module that will require additional expense and hassle. This is the direct, efficient, and cost-effective fix.
A Straightforward Guide to Installation
- ✔ 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 Cadillac DTS and Buick Lucerne, the ECM is typically found within the lower part of the air cleaner box assembly. On other GM models, it may be on the firewall or inner fender.
- ✔ Disconnect Connectors: Carefully release the locking tabs on the electrical connectors and pull them straight out from the module. Avoid pulling on the wires themselves.
- ✔ Remove the Old Module: Unbolt the old ECM from its mounting bracket. Keep the hardware, as you will reuse it for the new module.
- ✔ Install the New Module: Mount your new, pre-programmed ECM onto the bracket and securely fasten it.
- ✔ Reconnect Everything: Plug the electrical connectors firmly into the new module until they click into place. Reconnect the negative battery terminal.
- ✔ Final Step: In some cases, a security relearn procedure may be necessary. This can typically be done by turning the key to the ‘ON’ position for 10-15 minutes, then off, and repeating two more times before starting the engine.
Verified Vehicle Compatibility
This ECM is a direct replacement for service numbers 12636659, 12639300, 1263605, 12628993, 12628911, 12625453, 12622175, 12630464, and 12678512. It is guaranteed to fit the following vehicles:
- Cadillac CTS (2009): 6.2L
- Cadillac DTS (2009-2011)
- Cadillac SRX (2009): 4.6L
- Cadillac STS (2009-2010): 4.4L, 4.6L
- Cadillac XLR (2009): With ID 12636659 or 12625453
- 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)
Frequently Asked Questions
Frequently Asked Questions
Why do you need my VIN?
Your Vehicle Identification Number (VIN) allows us to program the ECM with the exact software and calibrations for your car’s specific options, engine, and transmission. This ensures perfect compatibility and function right out of the box, eliminating the need for dealer programming.
Is this a difficult part to install myself?
For most DIYers with basic tools, this is a straightforward installation. The primary steps involve disconnecting the battery, unplugging the old module, and swapping it with the new one. Since we program it beforehand, no special computer equipment is needed.
Will this fix my check engine light?
If the check engine light is caused by an internal failure of the original ECM (e.g., codes P0601-P0606), this part is the correct fix. However, you should always ensure your vehicle’s issues have been properly diagnosed, as other failing sensors or wiring problems can also cause a check engine light.
Are there any other steps after installation?
In many cases, the vehicle will start and run perfectly after installation. Some GM vehicles may require a simple ‘Security Relearn’ or ‘Crankshaft Variation Relearn’ procedure, which can often be performed without special tools. Instructions are widely available online or in service manuals.
Is this compatible with other part numbers?
Yes, this module is a direct replacement for a wide range of GM service numbers, including 12639300, 1263605, 12628993, 12628911, and others listed in the description. This ensures you are getting the correct, updated part for your vehicle.