Is Your Cadillac or Pontiac Running Rough?
If your 2004-2005 Cadillac DeVille, Seville, or Pontiac Bonneville is suffering from perplexing issues like stalling, poor fuel economy, a persistent Check Engine Light, or even a no-start condition, the culprit is often a failing Powertrain Control Module (PCM). This component is the central brain of your vehicle, managing everything from fuel injection and spark timing to transmission shifts. When it begins to fail, it can create a cascade of problems that are frustrating and difficult to diagnose. Don’t let a faulty computer keep your luxury sedan off the road. This is the reliable, straightforward solution you need.
From the Diagnostic Bay
We had a 2005 DeVille with the 4.6L Northstar V8 come in with a complaint of intermittent stalling at stoplights and a random P0601 (Internal Control Module Memory Check Sum Error) code. The owner had already replaced the spark plugs, coils, and even the fuel pump with no success. After hooking up our diagnostic tools, we noticed erratic data readings from multiple sensors that would flicker just before the engine would quit. Instead of a sensor issue, this pointed to the processor itself. We installed a VIN-programmed PCM just like this one, performed the security relearn procedure, and the car ran perfectly. It’s a classic case where chasing individual symptoms is futile because the core problem lies with the vehicle’s central computer.
The Simple Solution: A VIN-Programmed 2004-2005 DeVille PCM
This isn’t just a replacement part; it’s a complete, ready-to-install solution. We are offering a genuine, used OEM Powertrain Control Module, part number 12587465, that has been meticulously tested and is ready for service. The most critical part of the process is that we program the module to your vehicle’s specific Vehicle Identification Number (VIN) before it ships. This crucial step ensures that the computer has the correct software and calibrations for your car’s exact configuration, including its engine, transmission, and factory options. This process flashes the unit with the latest updates from General Motors, often resolving issues that were present even in the original factory software.
Symptoms of a Failing PCM
- ✔ Check Engine Light is on with seemingly unrelated error codes.
- ✔ Engine stalls, sputters, or idles erratically.
- ✔ Noticeable decrease in fuel efficiency.
- ✔ Harsh or incorrect automatic transmission shifting.
- ✔ The vehicle won’t start, even with a good battery and starter.
- ✔ Communication errors with diagnostic scan tools.
- ✔ Intermittent issues that disappear and reappear without a clear cause.
Guaranteed Fitment & Compatibility
This Electronic Control Module is a direct replacement for several service numbers, ensuring broad compatibility. Located in the left-hand (driver’s side) engine compartment, physical installation is straightforward for a DIY mechanic or any professional technician. Please verify that this part fits your vehicle using the information below:
- Pontiac Bonneville: 2004-2005 (with 4.6L engine)
- Cadillac DeVille: 2004
- Cadillac DeVille: 2005 (with ID 12587465)
- Cadillac Seville: 2004
This module is a direct replacement for the following service part numbers: 12587465, 12586547, 15576920.
IMPORTANT: After purchasing, you must provide us with your vehicle’s 17-digit VIN. We cannot ship your order until we have this information to properly program the module.
Frequently Asked Questions
Do I need to get this computer programmed?
No. We handle the programming for you before we ship the part. Simply provide your vehicle’s VIN during or after checkout, and we will flash the module with the correct GM software for your specific car.
What is a VIN and why do you need it?
The VIN is your car’s 17-digit Vehicle Identification Number, like a serial number. It contains critical information about your car’s make, model, engine, and factory-installed options. We use it to load the precise software and calibration files onto the PCM, ensuring it works perfectly with your vehicle.
Is any additional work needed after installation?
In most cases, you will need to perform a security relearn procedure (also known as a Passlock or anti-theft relearn). This process syncs the new PCM to your vehicle’s anti-theft system and ignition keys. It’s a simple procedure that typically takes 30 minutes and does not require special tools. We can provide instructions for this process.
Is this a new part?
No, this is a high-quality, tested, and fully functional used OEM part sourced from a salvaged vehicle. This allows us to provide a reliable, factory-correct part at a significant cost saving compared to a new unit from a dealership.
Where is the 2004-2005 DeVille PCM located?
The Powertrain Control Module on these vehicles is conveniently located in the engine compartment on the driver’s side, typically housed within the air filter box assembly for protection.