Restore Peak Performance to Your General Motors Vehicle
Is your 2003 Pontiac Grand Prix, Chevrolet Impala, or Buick Century suffering from perplexing issues like a persistent check engine light, erratic shifting, poor fuel economy, or even a no-start condition? The Powertrain Control Module (PCM), often called the vehicle’s main computer, is the central command for all engine and transmission functions. When it begins to fail, it can cause a cascade of frustrating and difficult-to-diagnose problems. This replacement PCM, part number 89017735, is the definitive solution to restore your vehicle’s reliability and drivability.
Unlike a generic module from a parts store or salvage yard, this unit is delivered to you fully programmed for your specific vehicle. We use the Vehicle Identification Number (VIN) you provide at checkout to flash the module with the latest, most stable software updates directly from General Motors. This critical step ensures seamless communication with all other modules in your car, proper engine and transmission operation, and correct function of all factory options. It’s a plug-and-play solution that eliminates the need for an expensive trip to the dealership for programming.
Diagnosing and Replacing Your 2003 Grand Prix PCM
A failing PCM can mimic a wide variety of other component failures, often leading to wasted time and money replacing perfectly good sensors and parts. If you’ve been chasing an intermittent issue without success, it’s time to consider the central computer. A faulty 2003 Grand Prix PCM can be the root cause of inconsistent performance that other diagnostics miss. Replacing it with this pre-programmed unit is a straightforward process that can be completed with basic hand tools, getting you back on the road with confidence.
From the Diagnostic Bay
We had a 2004 Chevrolet Impala come into the shop with a complaint of random stalling and harsh 1-2 shifting. The owner had already replaced the throttle position sensor and the mass airflow sensor, but the problem persisted. Scans showed no hard codes, just some intermittent communication errors. After verifying power and ground to the PCM, we suspected an internal module fault. We installed one of our pre-programmed PCMs, performed the 30-minute security relearn procedure right in the bay, and the car ran perfectly. It’s a classic case where the ‘brain’ was the issue, not the sensors it was reading.
Common Symptoms of a Failing PCM
- ✔ Check Engine Light: The light may be on continuously or intermittently, often with communication-related error codes (U-codes).
- ✔ Poor Engine Performance: Noticeable loss of power, hesitation during acceleration, rough idling, or engine misfires.
- ✔ Reduced Fuel Economy: The engine may run too rich or too lean, causing a sudden and significant drop in MPG.
- ✔ Transmission Issues: Harsh or delayed shifting, or the transmission may feel like it’s stuck in one gear (limp mode).
- ✔ Engine Stalling: The engine may stall for no apparent reason, either while driving or at idle.
- ✔ No-Start Condition: The engine cranks but will not start, often due to the PCM failing to control the fuel or ignition systems.
Guaranteed Compatibility
This module is a direct replacement for original equipment part numbers 89017735, 12583827, and 12583826. It is guaranteed to fit and function in the following vehicles:
- ALERO: 2003-2004 (3.4L)
- AZTEK: 2003-2005
- BONNEVILLE: 2004-2005 (3.8L)
- CENTURY: 2003-2005
- GRAND AM: 2003-2005 (3.4L)
- GRAND PRIX: 2003 (3.1L)
- IMPALA: 2003-2005
- LESABRE: 2004-2005
- MALIBU: 2003
- MONTE CARLO: 2003-2005
- MONTANA: 2003-2005
- PARK AVENUE: 2004-2005
- RENDEZVOUS: 2003-2005
- SILHOUETTE: 2003-2004
- VENTURE: 2003-2005
Note: Please provide your VIN upon purchase to ensure we program the correct software for your vehicle’s specific options and configuration.
Frequently Asked Questions
Do I need to have this module 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 specific to your car.
What is a VIN and where do I find it?
The VIN is your car’s unique 17-digit identification number. You can typically find it on a small plate on the driver’s side of the dashboard (visible through the windshield), on the driver’s side door jamb sticker, or on your vehicle’s registration and insurance documents.
Is any special procedure needed after installation?
Yes, in most cases you will need to perform a security relearn procedure, also known as an anti-theft relearn. This syncs the new PCM with your vehicle’s anti-theft system. It’s a simple process that typically involves turning the key to the ‘ON’ position for 10 minutes, three times in a row. Instructions are readily available online for your specific model.
How do I know if my PCM is the problem?
Diagnosing a faulty PCM can be tricky as its symptoms often overlap with other failing parts. A good first step is to have the vehicle scanned for trouble codes. If you see communication error codes (U-codes) or if you’ve replaced multiple sensors without fixing the issue, the PCM is a likely culprit.
Is this a new or used part?
This is a high-quality, tested, and inspected original equipment part that has been prepared for its next service life. Each unit is verified to be fully functional before being programmed and shipped.