Is Your Cadillac or GM Vehicle Running Rough?
If you’re experiencing perplexing issues like a persistent check engine light, poor fuel economy, stalling, or a no-start condition, the root cause might be a failing Engine Control Module (ECM). As the central computer for your vehicle’s engine, the ECM is responsible for managing everything from fuel injection and ignition timing to emissions controls and transmission shifting. When it fails, the symptoms can be widespread and frustrating, often mimicking other component failures. This can lead to costly and incorrect repairs if not diagnosed properly.
This listing is for a genuine, used GM Engine Control Module, part number 12633555, which also directly replaces part numbers 12653998, 12655007, and 12644446. We take the guesswork out of the replacement process. Before this module ships, we will program it specifically to your vehicle using the VIN you provide. This critical step ensures that the computer has the correct software and calibrations for your car’s specific engine, transmission, and options, loaded with the latest updates available from General Motors.
From the Diagnostic Bay
We once had a 2014 Cadillac SRX come in on a tow truck. The owner had already replaced the fuel pump and all six spark plugs trying to solve an intermittent no-start and stalling issue. The codes were all over the place—communication errors, misfires, sensor faults. After hours of chasing wires, we checked the 5-volt reference signal from the ECM and found it was dropping out randomly. The ECM was internally shorting and taking the whole network down with it. A pre-programmed replacement ECM like this one had the vehicle running perfectly in under an hour, saving the customer from further expensive and unnecessary part replacements.
Solving Problems with a Programmed 2014-2015 CTS ECM
A faulty ECM can be the hidden cause behind a host of drivability problems. By replacing your old, malfunctioning unit with this fully programmed module, you can restore your vehicle’s performance, reliability, and efficiency. Because we flash the unit with your vehicle’s specific VIN, it arrives ready for a much simpler installation process, often avoiding costly trips to the dealership for programming. This module is a reliable and cost-effective solution to get your vehicle back on the road and running as it should.
Common Symptoms of a Failing ECM
- ✔ Check Engine Light is illuminated with various, often inconsistent, trouble codes.
- ✔ Engine stalling, stumbling, or hesitating during acceleration.
- ✔ Noticeable decrease in fuel efficiency.
- ✔ The vehicle cranks but refuses to start.
- ✔ Automatic transmission shifting issues or harsh shifts.
- ✔ Communication errors with diagnostic scan tools.
- ✔ Misfire codes even after replacing plugs, coils, and injectors.
This module is a tested, used part sourced from a salvaged vehicle, providing a dependable solution at a fraction of the cost of a new unit. It’s compatible with a wide array of General Motors vehicles beyond the Cadillac CTS, including models like the Chevrolet Camaro, Malibu, Equinox, Traverse, Buick Regal, LaCrosse, Enclave, and GMC Acadia. Please review the detailed fitment list to confirm compatibility with your specific make, model, and year.
Frequently Asked Questions
Do I need to program this ECM?
No. We handle the programming for you before shipment. Simply provide your vehicle’s 17-digit VIN during or after checkout, and we will flash the module with the latest GM software for your specific car.
Is this a new part?
No, this is a high-quality, used OEM part that has been carefully inspected and sourced from a salvaged vehicle. It is guaranteed to be functional and is programmed to work like a new module.
What information do you need from me?
After you complete your purchase, we will need your vehicle’s complete 17-digit VIN (Vehicle Identification Number). This is crucial for us to load the correct software and calibrations for your car.
Will I need to perform any additional steps after installation?
In many cases, you may need to perform a security relearn procedure (often called a Passlock or anti-theft relearn) which can typically be done without special tools. Some vehicles may also require a Crankshaft Position Sensor Variation relearn, which requires a capable scan tool. Please consult your vehicle’s service manual or a professional technician.
How do I know if this ECM will fit my vehicle?
This ECM, part number 12633555, fits a wide range of GM vehicles. The best way to ensure compatibility is to match your original part number to one of the numbers listed (12633555, 12653998, 12655007, 12644446) and consult the detailed fitment list on this page.