Restore Peak Performance to Your Vehicle’s Powertrain
Is your Cadillac XLR, Corvette, or other GM vehicle suffering from perplexing issues like a persistent check engine light, rough idling, stalling, or a sudden drop in fuel economy? These are often hallmark signs of a failing Engine Control Module (ECM), the central computer that governs your engine’s every function. A faulty ECM can disrupt everything from fuel injection and ignition timing to transmission shifting, leaving you with an unreliable and inefficient vehicle. This genuine GM control unit, part number 12678512, is the definitive solution to restore your vehicle’s factory performance and reliability.
We had a 2009 Cadillac CTS-V come into the shop with a ghost of a problem. The owner complained of intermittent power loss and a check engine light that would come and go with no consistent codes. We checked the wiring, sensors, and fuel system, but everything tested fine. After hours of diagnostics, we decided to inspect the ECM. On the surface, it looked perfect, but a deep data scan revealed it was dropping communication packets under load. We replaced it with one of these pre-programmed units. The customer called a week later, ecstatic that his car had never run better. It’s a reminder that sometimes the most elusive problems trace back to the vehicle’s brain.
Common Symptoms of a Failing ECM
- ✔ Persistent Check Engine Light (CEL) that won’t clear.
- ✔ Unexplained loss of engine power or poor acceleration.
- ✔ Rough or erratic idling and frequent stalling.
- ✔ Noticeable decrease in fuel efficiency.
- ✔ Difficulty starting the engine or a complete no-start condition.
- ✔ Harsh or incorrect automatic transmission shifting.
- ✔ Communication errors with diagnostic scan tools.
The Plug-and-Play Solution: A Pre-Programmed 2009 XLR Engine Module
The biggest hurdle in replacing a modern ECM is the complex and expensive programming required at a dealership. We eliminate that step entirely. When you purchase this module, we use the Vehicle Identification Number (VIN) you provide to flash it with the latest, most stable GM-certified software specific to your vehicle’s configuration. This ensures that the module is ready for installation right out of the box, saving you hundreds of dollars in dealer programming fees and significant vehicle downtime. It’s a true plug-and-play solution designed for both professional technicians and savvy DIYers.
Guaranteed Compatibility and Interchangeability
This versatile control unit is a direct replacement for a wide range of GM vehicles. It is fully interchangeable with several service numbers, ensuring a perfect match for your application. If your original module has one of the following part numbers, this unit is the correct replacement:
Compatible Service Numbers: 12636659, 12639300, 1263605, 12628993, 12628911, 12625453, 12622175, 12630464, and 12678512.
This module fits an extensive list of models including the Cadillac STS, SRX, DTS, and XLR; Chevrolet Colorado, Trailblazer, and Corvette; GMC Envoy and Canyon; Hummer H3; and Saab 9-7x. Please verify your specific model and engine in the fitment list to confirm compatibility.
Frequently Asked Questions
Do I need to get this ECM programmed by a dealer?
No. We handle all the programming for you before shipment. Simply provide your vehicle’s VIN during checkout, and the module will arrive with the latest GM software specific to your car, ready for installation.
What is a VIN and where can I find it?
The VIN is your vehicle’s unique 17-digit identification number. You can typically find it on a plate on the driver’s side dashboard (visible through the windshield), on the driver’s side door jamb sticker, or on your vehicle’s registration and insurance documents.
Is installation difficult?
The physical installation is straightforward for anyone with basic mechanical skills, as it’s a direct-fit part. However, after installation, some GM vehicles may require a simple security relearn procedure (often called a Passlock or anti-theft relearn), which can usually be done without special tools. Instructions for this procedure are widely available online.
Will this part fix my check engine light?
If the check engine light and other symptoms are caused by a faulty ECM, this replacement part will resolve the issue. It’s crucial to ensure a proper diagnosis has been performed to confirm the ECM is the root cause of the problem.
What happens if I forget to provide my VIN?
Providing your VIN is essential for the programming service. If you do not provide it, we cannot program the module, and we will have to contact you to get the information, which will delay the shipment of your order.