Restore Peak Performance to Your Cadillac or Pontiac
Is your 2004 Cadillac Seville, DeVille, or 2004-2005 Pontiac Bonneville suffering from perplexing engine issues? The Powertrain Control Module (PCM), the electronic brain of your vehicle, is often the source of these frustrating problems. This genuine GM PCM, service number 12587465, is the definitive solution to get your vehicle running smoothly and reliably again. It arrives at your door pre-programmed with the latest GM software updates, specifically matched to your vehicle’s VIN. This eliminates the need for expensive dealership programming, making it a straightforward, effective repair.
From the Diagnostic Bay
We had a 2004 Cadillac DeVille come into the shop with a complaint of intermittent stalling and a transmission that seemed to have a mind of its own, shifting harshly at random. The owner had already replaced the throttle position sensor and a couple of ignition coils based on some generic trouble codes, but the problem persisted. After hooking up our professional scanner and monitoring live data, we saw erratic readings from multiple sensors that didn’t make sense together. This is a classic sign of a failing central computer. Instead of continuing to chase phantom sensor issues, we installed a VIN-programmed PCM. The car immediately ran perfectly, the transmission shifted like new, and all the strange data readings stabilized. It’s a reminder that when multiple, unrelated systems act up, it’s wise to look at the one component that controls them all: the PCM.
Diagnosing and Replacing Your 2004 Seville PCM
A failing PCM can manifest in a wide variety of symptoms that can easily be mistaken for other component failures. By controlling everything from fuel injection and ignition timing to transmission shift points and emissions systems, a faulty module can cause chaos throughout your vehicle’s powertrain. If you’re experiencing these issues, a failing PCM is a likely culprit.
Common Symptoms of a Failing PCM
- ✔ Check Engine Light: The light may be on with codes that point to various sensors, or it may illuminate intermittently for no apparent reason.
- ✔ Engine Stalling or Misfiring: Your engine might stall unexpectedly while driving or at idle, or you may experience rough running and misfires.
- ✔ Poor Fuel Economy: A malfunctioning PCM can’t properly manage the engine’s fuel delivery, leading to a noticeable drop in MPG.
- ✔ Harsh or Failed Shifting: The PCM controls the transmission. A bad module can cause delayed, hard, or erratic shifting.
- ✔ No-Start Condition: In cases of complete failure, the PCM may not be able to activate the fuel pump or ignition system, preventing the car from starting at all.
- ✔ Failed Emissions Test: Incorrect engine management will almost certainly lead to a failed smog or emissions inspection.
A Simple, Programmed Solution
This isn’t just a part in a box; it’s a comprehensive solution. We take a quality, used OEM module and program it using your vehicle’s specific VIN. This ensures that all factory settings, including those for the engine, transmission, and anti-theft system, are correctly configured for your exact car. When you receive the part, installation is as simple as disconnecting the battery, swapping the modules, and reconnecting the battery. You will need to perform a simple security relearn procedure, which can be done without any special tools. This process ensures your vehicle recognizes the new module and allows the engine to start.
Vehicle Fitment:
This module is a direct replacement for the following vehicles equipped with the specified options:
- 2004 Cadillac Seville: Electronic Control Module; (LH engine compartment)
- 2004 Cadillac DeVille: Electronic Control Module; (LH engine compartment)
- 2005 Cadillac DeVille: Electronic Control Module; (LH engine compartment), ID 12587465
- 2004-2005 Pontiac Bonneville: Electronic Control Module; (LH engine compartment), 4.6L
This part is compatible with service numbers 12587465, 12586547, and 15576920. Please provide your VIN upon purchase to ensure flawless programming and compatibility.
Frequently Asked Questions
Do I need to have this computer programmed?
No. We handle all the programming for you before shipment. Simply provide us with your vehicle’s VIN during or after checkout, and we will flash the module with the latest GM software for your specific car. It will be ready for installation when you receive it.
Is this a new part?
This is a high-quality, used OEM part sourced from a salvaged vehicle. Each unit is thoroughly inspected and tested to ensure it is fully functional before being programmed and shipped.
Where is the PCM located on my 2004 Seville?
The PCM, or Electronic Control Module, is located in the engine compartment on the left-hand (driver’s) side. It is typically housed within the air cleaner assembly.
What is the security relearn procedure?
After installing the new PCM, you will need to perform a simple security relearn. This typically involves turning the key to the ‘ON’ position for 10-15 minutes, then ‘OFF’ for 10 seconds, and repeating this cycle three times. This allows your vehicle’s anti-theft system to synchronize with the replacement 2004 Seville PCM. Specific instructions can be easily found online for your model.
Will this fix my transmission shifting problems?
In many cases, yes. The PCM is responsible for controlling the transmission’s electronic solenoids and interpreting sensor data to determine shift points. If the PCM is faulty, it can directly cause erratic or harsh shifting. If your transmission issues are caused by a faulty module, this part is the correct fix.