Is Your Buick Regal Running Rough, Stalling, or Showing a Check Engine Light?
If you’re dealing with frustrating engine problems in your 2003-2004 Buick Regal, a faulty Powertrain Control Module (PCM) is often the culprit. Over my 20+ years turning wrenches, I’ve seen these exact symptoms hundreds of times on GM’s 3.8L V6 platform. A bad PCM can cause intermittent stalling, no-start conditions, terrible fuel economy, erratic shifting, and a host of confusing diagnostic trouble codes that won’t go away. Don’t let a failing computer keep your reliable Regal off the road.
A Real-World Scenario: Just last month, a customer brought in his 2003 LeSabre, which uses this same module. It had a persistent P0601 (Internal Control Module Memory Check Sum Error) and would randomly die at stoplights. He’d already replaced the crank sensor and plugs. We swapped in one of our pre-programmed PCMs, and the car ran perfectly. It’s a common story, and the fix is straightforward when you have the right part.
The Direct Solution: A VIN-Programmed 2003-2004 Regal PCM
This isn’t just a generic, off-the-shelf part. This is a dependable Powertrain Control Module, service number 12583826, that we program specifically for your vehicle before it ships. We use your Vehicle Identification Number (VIN) to load the latest, most stable software updates directly from GM. This process ensures your vehicle’s engine, transmission, and emissions systems all communicate perfectly, restoring the performance and reliability you expect.
Key Benefits of Our Programmed PCM:
- ✔ VIN-Specific Programming: We flash the module with your car’s exact VIN, ensuring 100% compatibility.
- ✔ Latest GM Software: Your PCM arrives with all the newest drivability and performance updates from the manufacturer.
- ✔ No Dealer Required: This module is ready to install right out of the box. No expensive trip to the dealership for programming is necessary.
- ✔ Solves Common Issues: Directly addresses problems like false trouble codes, poor idle, hesitation, and communication errors.
- ✔ Direct-Fit Replacement: Guaranteed to fit and function just like the original factory module.
Plug-and-Play Installation: Get Back on the Road in Minutes
You don’t need to be a master mechanic to install this part. The PCM on these vehicles is located inside the air filter box housing for easy access.
- Safety First: Disconnect the negative terminal from your car’s battery.
- Locate the PCM: Open the air filter box on the driver’s side of the engine compartment. The PCM is the silver module held in place by clips.
- Disconnect the Old Module: Carefully unplug the electrical connectors. They have locking tabs that need to be released.
- Install the New PCM: Seat your new, pre-programmed module in the housing and securely plug in the connectors. You’ll hear a click when they’re properly seated.
- Reconnect Power: Re-attach the negative battery terminal.
- Perform Security Relearn (If Needed): In most cases, the car will start and run perfectly. Some vehicles may require a simple 10-30 minute key-cycle security relearn procedure, which can be done in your driveway without any special tools.
Expert Pro Tip: Before you plug in your new PCM, take a moment to inspect the harness connectors. Use a small brush and some quality electrical contact cleaner to remove any green or white corrosion from the pins. A poor connection is a common point of failure and can mimic the symptoms of a bad module.
Guaranteed Vehicle Compatibility
This module is a direct replacement for service numbers 12583826 and 89017735. It is guaranteed to fit the following vehicles:
- 2003-2004 Buick Regal (LH engine compartment)
- 2003 Buick LeSabre (ID 12583826)
- 2003-2004 Buick Park Avenue (LH front engine compartment)
- 2003 Pontiac Bonneville (ID 12583826)
- 2003 Pontiac Grand Prix (3.8L, ID 12583826)
- 2003 Chevrolet Impala (3.8L, ID 12583826 or 89017735)
- 2003 Chevrolet Monte Carlo (3.8L, ID 12583826)
IMPORTANT: After purchasing, please send us your vehicle’s 17-digit VIN. We cannot ship your order until we have this information to program your module.