Restore Peak Performance to Your GM 3.8L Engine
Is your 2003-2004 Buick Regal or other GM vehicle suffering from frustrating, hard-to-diagnose issues? A faulty Powertrain Control Module (PCM), the central computer of your vehicle, is often the hidden culprit behind poor engine performance, erratic transmission shifting, and persistent Check Engine lights. This replacement PCM, service number 89017735, is the definitive solution to get your car running smoothly and reliably again. Forget about expensive dealership visits and programming fees. We handle the critical first step for you.
Upon purchase, simply provide us with your vehicle’s VIN. Our technicians will then program the module with the latest GM-certified software specific to your car. This ensures that all factory parameters for fuel delivery, ignition timing, and transmission control are perfectly restored. This isn’t just a part; it’s a plug-and-play solution designed to solve the problem correctly the first time.
From the Diagnostic Bay: The Intermittent Stall Mystery
I remember a 2003 Buick LeSabre with the 3.8L engine that came into my shop with a maddeningly intermittent stalling problem. The owner had already replaced the fuel pump and crank sensor with no luck. Scans showed no hard codes, just a history of random communication errors. After monitoring live data, I noticed the PCM’s voltage would momentarily drop just before a stall. On the bench, we found a hairline crack in the circuit board, a classic sign of thermal stress failure. Replacing the PCM with a pre-programmed unit like this one solved the issue instantly. It’s a reminder that with modern electronics, the symptoms aren’t always straightforward, but the fix can be.
Common Signs of a Failing PCM
If you’re experiencing any of the following, a failing engine computer could be the cause. In my 20+ years of experience, these are the most frequent indicators I’ve seen with these specific GM models.
- ✔ Check Engine Light is on with internal processor codes (e.g., P0601, P0602, P0606).
- ✔ The engine cranks but refuses to start.
- ✔ Unexplained drops in fuel economy.
- ✔ Harsh or erratic automatic transmission shifting.
- ✔ The vehicle stalls for no apparent reason, either while driving or at idle.
- ✔ Communication loss with your scan tool.
Your Guide to a Straightforward Installation
Installing your new 2003-2004 Regal PCM is a manageable job for a DIYer with basic tools. The most critical part is the security relearn procedure, which pairs the new module to your car’s anti-theft system. It requires no special tools, just a little time.
- Safety First: Disconnect the negative terminal from your vehicle’s battery to prevent any electrical shorts.
- Locate the PCM: On most of these vehicles, the PCM is located inside the air filter box housing in the left (driver’s side) of the engine compartment.
- Disconnect and Remove: Carefully unplug the wiring harness connectors. They have locking tabs that need to be released. Then, unbolt the old module from its mounting bracket.
- Install the New PCM: Mount the new module and securely reconnect the wiring harnesses. Ensure they click into place. Reconnect the vehicle’s battery.
- Perform Security Relearn (Crucial Step): Turn the key to the ‘ON’ position (don’t start the engine). The security light should be on or flashing. Leave the key on for 10-12 minutes, or until the light turns off. Turn the key off for 10 seconds. Repeat this cycle two more times (for a total of three cycles, about 30 minutes). After the third cycle, the vehicle will be paired and should start.
Verified Vehicle Compatibility List
This module is a direct-fit replacement for the original part number 89017735 or 12583826. Please verify your vehicle and options below to ensure proper fitment.
- 2003-2004 Buick Regal (Electronic Control Module; LH engine compartment)
- 2003 Buick LeSabre (Electronic Control Module; LH engine compartment, ID 12583826)
- 2003-2004 Buick Park Avenue (Electronic Control Module; LH front engine compartment, ID 12583826 for ’04)
- 2003 Chevrolet Impala (Electronic Control Module; LH engine compartment, 3.8L, ID 12583826 or 89017735)
- 2003 Chevrolet Monte Carlo (Electronic Control Module; LH engine compartment, 3.8L, ID 12583826)
- 2003 Pontiac Bonneville (Electronic Control Module; LH engine compartment, ID 12583826)
- 2003 Pontiac Grand Prix (Electronic Control Module; LH front engine compartment, 3.8L, ID 12583826)
Do I need to get this programmed by a dealer?
Do I need to get this programmed by a dealer?
No! That’s the primary benefit of our service. We program the Powertrain Control Module to your car’s specific VIN before we ship it. This saves you the time, hassle, and expense of a dealership visit. You will only need to perform the simple, 30-minute security relearn procedure at home.
What information do you need from me?
After you complete your purchase, we will need your 17-digit Vehicle Identification Number (VIN). This is typically found on your driver’s side dashboard (viewable through the windshield) or on your vehicle’s registration and insurance documents.
Is this part the same as an ECM?
Yes. The terms Powertrain Control Module (PCM) and Engine Control Module (ECM) are often used interchangeably for this component. It is the main computer that controls the engine and, in many cases, the transmission functions.
Will this fix my car’s hard starting issue?
A faulty PCM is a very common cause of no-start or hard-start conditions, as it controls both fuel injection and spark timing. While other issues can cause this symptom (like a bad fuel pump or crank sensor), if you’ve ruled those out or have diagnostic codes pointing to the PCM, this part is the correct solution.