Restore Peak Performance to Your Cadillac or Pontiac
Is your 2004 Cadillac Seville, DeVille, or 2004-2005 Pontiac Bonneville suffering from frustrating issues like intermittent stalling, a persistent check engine light, poor fuel economy, or erratic shifting? These are common indicators of a failing Powertrain Control Module (PCM), the central computer that manages your vehicle’s engine and transmission. Don’t let a faulty computer keep your luxury vehicle off the road. This genuine, used OEM PCM, service number 12587465, is the reliable and effective solution to get your car running smoothly again.
From the Diagnostic Bay
We had a 2004 Cadillac DeVille come into the shop that was a real head-scratcher. The owner complained of random stalling at stoplights and a check engine light that would come and go. We checked for vacuum leaks, tested sensors, and cleaned the throttle body, but the problem persisted. The scanner showed a P0601 code (Internal Control Module Memory Check Sum Error), a dead giveaway for a failing PCM. Instead of just swapping in a blank unit from a junkyard, which would require expensive dealership programming, we sourced a quality-tested used module like this one. We flashed it with the customer’s VIN and the latest GM software right here. After a 15-minute install and a quick security relearn, the car ran perfectly. The customer was thrilled to have their smooth, reliable Cadillac back without the massive dealership bill.
Common Symptoms of a Failing 2004 Seville Engine Computer
A failing engine computer can manifest in numerous ways, often mimicking other component failures. If you’re experiencing any of the following, your PCM could be the culprit:
- ✔ Persistent Check Engine Light (CEL) with codes related to internal processor failure (e.g., P0601, P0606).
- ✔ Vehicle refuses to start or has difficulty starting, even with a good battery and starter.
- ✔ Unexplained engine stalling, especially when coming to a stop or at idle.
- ✔ Noticeable decrease in fuel efficiency.
- ✔ Rough idling, engine misfires, or poor acceleration.
- ✔ Harsh or erratic automatic transmission shifting.
- ✔ Failure to communicate with diagnostic scan tools.
The Plug-and-Play Solution: Programmed to Your VIN
What sets this PCM apart is our professional programming service. This isn’t just a used part pulled from a shelf; it’s a complete solution. Before we ship it, our technicians will use your vehicle’s unique Vehicle Identification Number (VIN) to flash the module with the correct, factory-specified software and the latest updates from General Motors. This critical step ensures that the computer works seamlessly with your car’s specific systems, including the engine, transmission, anti-theft system, and all factory options. This eliminates the need for expensive and time-consuming trips to the dealership for programming.
This unit is a direct replacement for service numbers 12587465, 12586547, and 15576920. Please verify your original part number before ordering.
Installation and Relearn Procedures
While this module is programmed for your vehicle, installation may require a final step known as a security relearn or anti-theft relearn procedure. This syncs the new computer with your car’s keys and security system. In many cases, this can be done without special tools. Additionally, a Crankshaft Position Sensor Variation (CASE) relearn may be needed with a compatible scan tool to ensure optimal engine timing and prevent misfire codes. We recommend installation by a qualified mechanic to ensure these procedures are completed correctly.
Guaranteed Fitment
This electronic control module is a confirmed fit for the following vehicles:
- Pontiac Bonneville: 2004-2005 (4.6L Engine)
- Cadillac DeVille: 2004-2005 (ID 12587465)
- Cadillac Seville: 2004
Frequently Asked Questions
Do I need to have this computer programmed?
No. The main benefit of this part is that we handle the programming for you before it ships. Simply provide your VIN during or after checkout, and it will arrive ready to be installed and synchronized with your vehicle.
What is a VIN and where can I find it?
The VIN (Vehicle Identification Number) is a unique 17-digit code for your car. You can typically find it on a metal 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 this a new part?
No, this is a high-quality, tested, and fully functional used OEM (Original Equipment Manufacturer) part sourced from a salvaged vehicle. This ensures a perfect fit and reliable operation at a fraction of the cost of a new unit.
What other steps are required after I install it?
After physical installation, you will likely need to perform a security relearn procedure to sync the computer with your car’s anti-theft system. A Crankshaft Position (CASE) relearn may also be necessary to prevent false misfire codes. We recommend consulting a service manual or a professional mechanic for these final steps.
Will this part fix my vehicle’s problem?
This part will correct issues caused by a faulty PCM. However, it is crucial that your vehicle has been properly diagnosed. If your problem is caused by a bad sensor, wiring issue, or another component, replacing the PCM will not resolve the issue. We highly recommend a thorough diagnosis before ordering.