Is Your Pontiac Bonneville or Cadillac Running Poorly?
If your 2004-2005 Pontiac Bonneville, or 2004-2005 Cadillac DeVille/Seville is suffering from frustrating issues like stalling, a persistent check engine light, rough idling, or a no-start condition, a failing Powertrain Control Module (PCM) could be the culprit. The PCM is the central computer of your vehicle, managing everything from fuel mixture and ignition timing to transmission shifting. When it fails, the symptoms can be unpredictable and difficult to diagnose, leaving you stranded and facing a costly repair bill at the dealership.
The Smart Solution: A VIN-Programmed 2004-2005 Bonneville PCM
Don’t let a faulty engine computer keep your car off the road. This is a genuine, road-tested OEM Powertrain Control Module, service number 12587465, that offers a reliable and cost-effective solution. We take the guesswork and complexity out of the repair by professionally programming the module to your vehicle’s specific Vehicle Identification Number (VIN) before it ships. This crucial step ensures that the computer communicates perfectly with your car’s existing systems, including the anti-theft system, sensors, and other modules. This is the same process a dealership uses, but without the high cost and hassle.
From the Diagnostic Bay
We had a 2005 Cadillac DeVille come in on a tow truck. The owner had replaced the spark plugs, ignition coils, and even the fuel pump chasing an intermittent stalling problem that never set a clear trouble code. After hours of diagnostics, we hooked up our scope and monitored the PCM’s driver circuits. We found that the injector driver for cylinder 3 was dropping out randomly when the module got warm. A new, programmed PCM was the fix. The owner was frustrated by the money spent on other parts, but relieved to finally have a reliable car again. This highlights how a failing PCM can mimic many other component failures.
Common Symptoms of a Failing GM PCM
- ✔ Persistent Check Engine Light (CEL) with various codes
- ✔ Engine stalling or shutting off while driving
- ✔ Rough or erratic idling
- ✔ Difficulty starting the engine or a complete no-start condition
- ✔ Noticeable decrease in fuel economy
- ✔ Harsh or incorrect automatic transmission shifting
- ✔ Communication errors with diagnostic scan tools
Guaranteed Compatibility and Simple Installation
This module is a direct replacement for several service numbers, including 12587465, 12586547, and 15576920. It is meticulously inspected and sourced from a salvaged vehicle, providing OEM quality and durability. By providing us with your VIN during checkout, you ensure that the unit you receive is loaded with the latest GM software updates for your specific vehicle, making installation as straightforward as possible. In most cases, you simply disconnect the battery, swap the modules, and reconnect the battery. Some vehicles may require a simple security relearn procedure, which can typically be done without special tools.
This 2004-2005 Bonneville PCM is the definitive solution to restore your vehicle’s performance, reliability, and drivability. Get your car back on the road quickly and confidently.
Fitment Guide:
- Pontiac Bonneville: 2004-2005 (4.6L Engine, Located in LH engine compartment)
- Cadillac DeVille: 2004-2005 (Located in LH engine compartment, verify ID 12587465 for 2005)
- Cadillac Seville: 2004 (Located in LH engine compartment)
Frequently Asked Questions
Why do you need my vehicle’s VIN?
Your VIN (Vehicle Identification Number) is essential for programming the PCM. It allows us to load the exact software and calibrations specific to your car’s engine, transmission, and options. This ensures seamless integration and proper function, preventing compatibility issues and error codes.
Is this part ready to install when I receive it?
Yes! Because we program the module to your VIN before shipping, it arrives ready for installation. In most cases, it is a plug-and-play process. Some vehicles may require a security relearn procedure, which is a simple process you can often do yourself. Instructions can be readily found online or in your vehicle’s service manual.
Is this a new part?
This is a high-quality, used OEM (Original Equipment Manufacturer) part that has been carefully sourced from a salvaged vehicle. Each unit is tested to ensure it is fully functional. This provides the reliability of a genuine GM part at a fraction of the cost.
Where is the PCM located on my vehicle?
For the specified Bonneville, DeVille, and Seville models, the Powertrain Control Module is located in the engine compartment on the left-hand (driver’s) side, typically housed within the air filter box assembly for protection.
What if my original part number is different?
This module, service number 12587465, is a direct replacement for compatible service numbers 12586547 and 15576920. As long as your vehicle is listed in the fitment guide, this programmed module will function correctly.