Is your 2009 Cadillac CTS suffering from perplexing issues like a persistent check engine light, rough idling, stalling, or poor fuel economy? These are classic signs of a failing Engine Control Module (ECM), the central computer that governs your vehicle’s performance. Don’t let a faulty computer compromise the luxury and power you expect from your Cadillac. This genuine GM Engine Control Module, part number 1263605, is the definitive solution to restore your vehicle’s peak operational status.
This isn’t just a replacement part; it’s a fully integrated solution. We take the guesswork and extra expense out of the repair process by programming the module specifically for your vehicle before it ever leaves our facility. Simply provide your vehicle’s VIN (Vehicle Identification Number) during checkout, and our technicians will flash the unit with the latest, most stable software updates directly from General Motors. This ensures perfect communication between the ECM and all other vehicle systems, including the transmission, anti-lock brakes, and security system.
Common Symptoms of a Failing ECM
- ✔ Persistent Check Engine Light (CEL) with various trouble codes.
- ✔ Unexplained drops in fuel efficiency.
- ✔ Engine stalling, stumbling, or hesitating during acceleration.
- ✔ Rough or erratic idling.
- ✔ Harsh or incorrect automatic transmission shifting.
- ✔ Difficulty starting the engine or a complete no-start condition.
- ✔ Misfire codes even after replacing spark plugs and coils.
From the Diagnostic Bay
We had a 2009 CTS 6.2L come into the shop with a complaint of erratic shifting and a flashing check engine light. The owner had already spent a small fortune at another shop on transmission sensors and a fluid flush, with no improvement. Our lead tech scanned the vehicle and noticed communication errors between the TCM (Transmission Control Module) and the ECM. Instead of diving into the transmission, he focused on the data stream from the engine computer. He found inconsistent readings from the throttle position sensor, but the sensor itself tested fine. The culprit? A failing processor inside the original ECM was sending corrupt data, confusing the transmission. A new, properly programmed 2009 CTS Engine Module solved both the shifting problem and the check engine light, saving the customer from an unnecessary transmission rebuild.
The Plug-and-Play Solution: Your 2009 CTS Engine Module
Replacing an ECM can be a daunting task, often requiring expensive trips to the dealership for programming. We eliminate that step. By programming the module to your VIN, we ensure it’s ready for installation right out of the box. This process correctly sets up all the vehicle-specific parameters, including the anti-theft system (VATS/Passlock), so you won’t be stranded with a car that won’t start after the swap. Once installed, a simple “case learn” or crankshaft position sensor relearn procedure with a capable scan tool is typically all that’s needed to finalize the process and get you back on the road.
Guaranteed Compatibility
This ECM is a direct replacement for a wide range of GM vehicles. It is interchangeable with the following service numbers, ensuring a perfect fit and function:
- 12636659
- 12639300
- 1263605
- 12628993
- 12628911
- 12625453
- 12622175
- 12630464
- 12678512
This unit is confirmed to fit the following vehicles, among others:
- 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)
- 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)
- Buick Lucerne (2009-2011) – 4.6L
- Saab 9-7x (2009)
Choosing this pre-programmed 2009 CTS Engine Module is the smartest way to fix complex electronic issues, restoring the precise engine management your vehicle was designed with from the factory.
Frequently Asked Questions
Do I need to get this module programmed by a dealer?
No. We handle the programming for you before shipment. Simply provide your vehicle’s VIN at checkout, and the module will arrive ready for installation.
Where is the ECM located on my 2009 Cadillac CTS?
On the 2009 CTS, the Engine Control Module is typically located in the right-hand (passenger side) front of the engine compartment. Always disconnect the battery before attempting replacement.
What is a ‘case learn’ or ‘crankshaft variation relearn’?
This is a simple procedure required by most GM vehicles after an ECM replacement. It synchronizes the new ECM with the crankshaft position sensor to prevent misfire codes. A mechanic with a professional-grade scan tool can perform this in a few minutes.
How do I provide my VIN?
You can add your 17-digit VIN to the notes section during the checkout process. If you forget, we will contact you via email to retrieve it before we program and ship your part.
Will this fix my check engine light?
If the check engine light is caused by a faulty ECM, then yes, this part will resolve the issue. However, the light can be triggered by other failing components. It’s always best to have the vehicle properly diagnosed to confirm the ECM is the root cause of the problem.