Restore Peak Performance to Your GM Vehicle
If you’re dealing with frustrating engine problems in your 2009 Cadillac XLR—like intermittent stalling, a persistent Check Engine Light, or a complete no-start situation—a failing Engine Control Module (ECM) is often the culprit. As the central computer for your powertrain, a faulty ECM can cause a cascade of issues that are difficult to diagnose. This replacement Engine Control Module, part number 12630464, is the definitive solution to get your vehicle running reliably again. We take the guesswork and hassle out of the repair by programming the module to your vehicle’s specific VIN before it ever leaves our facility. This ensures it arrives ready for installation, loaded with the latest factory software from GM.
Is Your Vehicle Showing These Telltale Signs?
A failing ECM can manifest in many ways. I’ve seen these exact symptoms hundreds of times in my shop. If you’re experiencing any of the following, this module is likely the fix you need:
- ✔ Engine cranks but refuses to start.
- ✔ Unexplained stalling or rough idling, especially when warm.
- ✔ Noticeable decrease in fuel economy.
- ✔ The cooling fans run constantly, even when the engine is cold.
- ✔ Communication error codes, such as U0100 (Lost Communication With ECM/PCM).
- ✔ Internal module failure codes, like the dreaded P0601, P0603, or P0606.
- ✔ Transmission shifting issues or erratic behavior.
A Technician’s Notebook: The Intermittent No-Start Mystery
A customer brought in a 2009 Cadillac STS 4.6L with a problem that had stumped two other shops: it would randomly fail to start, but only after being driven for over an hour on a hot day. It threw no consistent codes, just a generic communication fault now and then. We suspected a heat-related failure. Instead of just replacing parts, I used a heat gun to carefully warm the ECM while monitoring data. Sure enough, once the module reached about 150°F, the datastream to my scan tool would drop out completely and the car wouldn’t start. After it cooled, it fired right up. This confirmed a hairline fracture on the ECM’s internal circuit board. A new, properly programmed 2009 XLR Engine Module (which shares the same architecture) solved the problem permanently. This is a classic example of how thermal stress can cause internal ECM failure that seems impossible to trace.
Your Straightforward Installation Guide
Replacing the ECM is a task many DIYers can handle. With our pre-programmed module, you skip the most difficult step. Just follow this general process:
- Safety First: Always disconnect the negative terminal from your vehicle’s battery before starting any electrical work.
- Locate the Module: On the 2009 XLR, the ECM is typically found in the right-hand front of the engine compartment. Consult a service manual for your specific vehicle if you’re unsure.
- Disconnect Connectors: Carefully unlatch and remove the electrical harness connectors from the old module. Inspect them for any corrosion or bent pins.
- Remove Old ECM: Unbolt the old module from its mounting bracket. There are usually a few 10mm bolts holding it in place.
- Install New ECM: Mount the new module securely in the bracket and re-attach the electrical connectors. Ensure they click firmly into place.
- Reconnect Battery: Re-attach the negative battery terminal.
- Perform Security Relearn: On many GM vehicles, a security relearn procedure is required for the car to start. This typically involves turning the key to ‘ON’ for 10-15 minutes, then ‘OFF’, and repeating two more times. This allows the new ECM to sync with your vehicle’s anti-theft system.
Guaranteed Fitment for Your Vehicle
This module is a direct replacement for a wide range of GM vehicles and is interchangeable with multiple service numbers, including 12636659, 12639300, 12628993, and more. Please verify your vehicle is on the list below for guaranteed compatibility.
- Cadillac CTS (2009, 6.2L)
- Cadillac DTS (2009-2011)
- Cadillac Lucerne (2009-2011, 4.6L)
- Cadillac SRX (2009, 4.6L)
- Cadillac STS (2009-2010, 4.4L/4.6L)
- Cadillac XLR (2009, 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)
- Saab 9-7X (2009)
This 2009 XLR Engine Module is the heart of your vehicle’s operation. Ordering our VIN-programmed unit is the most reliable way to restore its function and get you back on the road with confidence.
Frequently Asked Questions
Do I need to do any programming myself?
No. We handle all the programming before shipping. You just need to provide your vehicle’s 17-digit VIN during checkout. The module arrives ready to be installed.
Is this a simple plug-and-play installation?
Mostly, yes. After physical installation, you will likely need to perform a security relearn procedure, which does not require any special tools. We include instructions for this simple process.
Will this fix my specific problem?
This module corrects issues directly caused by a failing ECM, including many no-start, stalling, and communication code problems. While it’s a very common point of failure, you should always ensure your vehicle has been properly diagnosed.
What if I order the wrong part?
By providing your VIN, we verify compatibility before programming. This vital step prevents you from receiving the wrong part and ensures it’s the correct hardware and software for your vehicle’s options.
Are there any other part numbers this is compatible with?
Yes, this ECM is a direct replacement for several service numbers, including 12636659, 12639300, 12628993, 12625453, 12630464, and 12678512, among others.