Restore Peak Performance to Your Cadillac or Pontiac
Is your 2004-2005 Cadillac DeVille, Seville, or Pontiac Bonneville suffering from perplexing issues like stalling, rough idling, no-start conditions, or a persistent Check Engine Light? These are classic signs of a failing Powertrain Control Module (PCM), the electronic brain of your vehicle. A malfunctioning PCM can disrupt everything from fuel delivery and spark timing to transmission shifting, leaving you with an unreliable and frustrating driving experience. Don’t let a faulty computer keep your luxury vehicle off the road. This genuine, used OEM PCM is the reliable and cost-effective solution you need.
This unit, service number 12587465, is a direct replacement for your original module. We take the guesswork and high dealership costs out of the equation. Before this part ships, our technicians will program it with the latest GM software updates, specifically flashed to your vehicle’s unique Vehicle Identification Number (VIN). This critical programming step ensures that the computer communicates flawlessly with your car’s specific systems and options, making for a smoother installation and restoring its original factory performance.
From the Diagnostic Bay
We once had a 2004 Cadillac Seville come into the shop with a complaint of intermittent stalling 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. The symptoms were erratic, making diagnosis tricky. After confirming the power and ground circuits to the PCM were solid, we knew the module itself was the culprit. These units can fail internally, causing phantom issues that seem unrelated. We installed a VIN-programmed replacement like this one, performed the security relearn, and the car ran perfectly. It’s a great reminder that when electronics are involved, the central computer is often the root cause of the most confusing problems.
Common Symptoms of a Failing PCM
- ✔ Unexplained Check Engine Light illumination
- ✔ Engine stalling or shutting off while driving
- ✔ Rough or erratic engine idling
- ✔ Difficulty starting the engine or a complete no-start condition
- ✔ Poor fuel economy
- ✔ Harsh or incorrect automatic transmission shifting
- ✔ Communication errors with diagnostic scan tools
- ✔ False sensor codes being stored in memory
Your Pre-Programmed 2004-2005 DeVille PCM Solution
Finding the right part is only half the battle; ensuring it works correctly is paramount. This is where our programming service makes all the difference. A PCM from a salvage vehicle will not work correctly if simply swapped into your car due to the anti-theft systems and specific vehicle calibrations. Our process ensures you receive a part that is ready for installation. Simply provide us with your VIN during checkout or via message, and we handle the complex flashing process. This saves you a trip to the dealership and the expensive programming fees they charge.
Guaranteed Compatibility
This Electronic Control Module is a direct fit for the following vehicles. Please verify your original part number matches one of the service numbers listed below to ensure compatibility.
- Pontiac Bonneville: 2004-2005 (4.6L Engine)
- Cadillac DeVille: 2004-2005 (LH engine compartment)
- Cadillac Seville: 2004 (LH engine compartment)
Compatible Service Numbers: 12587465, 12586547, 15576920
Simple Installation Process
While professional installation is always recommended, replacing the PCM is a straightforward process for the experienced DIYer. After receiving your pre-programmed module:
- Disconnect the Battery: Always disconnect the negative battery terminal before working on any vehicle electronics.
- Locate the PCM: On these models, it is typically found in the engine compartment on the driver’s side (LH).
- Swap the Modules: Carefully disconnect the wiring harnesses and remove the old PCM. Install the new unit and securely reconnect the harnesses.
- Reconnect the Battery: Reattach the negative battery terminal.
- Perform Security Relearn (If Necessary): In most cases, you will need to perform a simple security relearn procedure, also known as a Passlock or VATS relearn. This typically involves turning the key to the ‘ON’ position for 10-15 minutes, then off, and repeating two more times. This allows the new PCM to sync with your vehicle’s anti-theft system. Instructions for this procedure are widely available online for your specific model.
By purchasing this programmed 2004-2005 DeVille PCM, you are getting a quality-tested, OEM part that solves your vehicle’s issues without the dealership price tag. Restore the reliability and smooth operation of your Cadillac or Pontiac today.
Frequently Asked Questions
Why do you need my VIN?
Your Vehicle Identification Number (VIN) is essential for programming the PCM correctly. It contains specific information about your car’s engine, transmission, options, and anti-theft system. Flashing the module with your VIN ensures it works perfectly with your exact vehicle configuration.
Is this a plug-and-play part?
Because we program it to your VIN before shipping, it is as close to plug-and-play as possible. However, you will likely need to perform a security relearn procedure after installation, which is a simple process that takes about 30 minutes and does not require special tools.
This part is used. How can I be sure it works?
This PCM is a genuine OEM part sourced from a salvaged vehicle. Each unit is inspected and tested to ensure it is fully functional before being programmed and shipped. We guarantee it will be in good working condition upon arrival.
Will this fix my Check Engine Light?
If the Check Engine Light is on due to a faulty PCM (e.g., internal error codes), then yes, this replacement part will resolve the issue. It is crucial to properly diagnose the problem first to ensure the PCM is the root cause and not a separate sensor or wiring issue.
What if I have a different part number?
This module replaces several service numbers, including 12587465, 12586547, and 15576920. As long as your vehicle model and year are listed in the compatibility chart and your original part number is one of these, this unit will work for you.