Restore Your Truck’s Core Performance and Reliability
Is your 2003 GMC Sierra 2500 or other compatible GM vehicle suffering from baffling electrical gremlins? Unexplained check engine lights, poor fuel mileage, erratic shifting, or even a no-start condition can often be traced back to one component: a failing Powertrain Control Module (PCM). As the central computer, the PCM manages everything from fuel injection and ignition timing to transmission shifting. When it falters, the symptoms can be frustrating and difficult to diagnose. This replacement PCM, part number 89017733, is the definitive solution to restore your vehicle’s factory-spec operation.
Case Study: The Ghost in the Machine
I remember a 2003 Silverado 2500 with the 8.1L that came into my shop. The owner was at his wit’s end. He’d replaced the throttle body, multiple sensors, and was still getting random stalling and a persistent U0100 ‘Lost Communication’ code. My scan tool could barely talk to the computer. After verifying the wiring and grounds were solid—a critical first step—all signs pointed to an internal PCM failure. We installed one of our pre-programmed modules, and it was like flipping a switch. The truck fired up instantly, idled smoothly, and all communication was restored. This isn’t just a part; it’s the end of a diagnostic nightmare.
Is Your GM Vehicle Showing These Signs of PCM Failure?
A failing computer can manifest in numerous ways. If you’re experiencing any of the following, a faulty PCM is a likely culprit. In my 20+ years of experience, these are the most common indicators I see in the shop:
- ✔ Check Engine Light (CEL) is on with communication codes (like U0100) or internal processor fault codes (P0601, P0602, P0606).
- ✔ The engine cranks but refuses to start.
- ✔ Unexplained drops in fuel economy.
- ✔ Harsh or erratic automatic transmission shifting.
- ✔ Engine stalling or sputtering intermittently.
- ✔ Multiple unrelated sensor codes appearing at once.
A Straightforward Guide to Installation
Replacing the 2003 Sierra 2500 Powertrain Control Module is a job most DIYers can handle with basic tools. Our pre-programming service means you won’t need a trip to the dealership for expensive flashing.
- Safety First: Always disconnect the negative battery terminal and wait a few minutes for the system to discharge completely.
- Locate the PCM: On most Sierra/Silverado trucks, the PCM is located under the hood on the driver’s side, often beneath or next to the battery tray. On Express/Savana vans, it’s typically in the LH rear of the engine compartment.
- Disconnect Connectors: Carefully release the locking tabs on the electrical harness connectors and pull them straight out. Never force them. Inspect the pins for any corrosion or damage.
- Remove the Old Module: Unbolt the PCM from its mounting bracket. It’s usually held by a few small bolts.
- Install the New Module: Mount your new, pre-programmed PCM and securely tighten the bolts. Reconnect the electrical harnesses, ensuring they click firmly into place.
- Reconnect Battery: Reattach the negative battery terminal. The vehicle may require a security relearn or Crankshaft Variation (CASE) relearn, which can often be completed with a series of key cycles or by driving.
Verified Vehicle Compatibility
This module is a direct replacement for service number 89017733 and many others. It is guaranteed to fit the following vehicles, provided the options match. We program it specifically for your vehicle’s VIN.
- AVALANCHE 2500 03: Electronic Control Module; (LH front under battery)
- ASTRO 03: Electronic Control Module; (LH front by battery)
- BLAZER S10/JIMMY S15 03: Electronic Control Module; (RH front engine compartment)
- CTS 04: Electronic Control Module; (RH engine compartment), Base, ID 12581565
- CORVETTE 04: Electronic Control Module; (RH engine compartment), ID 12581565
- EXPRESS/SAVANA VANS (1500, 2500, 3500) 03: Electronic Control Module; (LH rear engine compartment)
- S10/S15/SONOMA 03: Electronic Control Module; (RH front engine compartment), 4.3L
- SAFARI (GMC) 03: Electronic Control Module; (LH front by battery)
- SIERRA/SILVERADO 1500 PICKUP 03: Electronic Control Module; (LH front under battery), w/4.3L
- SIERRA/SILVERADO 2500 PICKUP 03: Powertrain Control Module; (LH front under battery), gasoline, 8.1L
- SIERRA/SILVERADO 3500 PICKUP 03: Engine Control Module; (LH front under battery), gasoline, 8.1L
- SUBURBAN 2500 03: Electronic Control Module; (LH front under battery), 8.1L
- YUKON XL 2500 03: Electronic Control Module; (LH front under battery), 8.1L
Frequently Asked Questions About Your 2003 Sierra 2500 Powertrain Control Module
Frequently Asked Questions
How does the VIN programming work?
After you place your order, you’ll need to provide us with your vehicle’s 17-digit VIN. We use this to load the latest, most stable GM-approved software directly onto the module, making it a true plug-and-play part for your specific vehicle.
Will I need to do anything after installing this PCM?
In many cases, no. However, some GM vehicles may require a simple security relearn procedure (often just key cycles) or a Crankshaft Position (CASE) relearn to clear a specific code. This is a normal part of the process and can often be done without special tools.
Is this the same as an ECM or Engine Computer?
Yes. The terms Powertrain Control Module (PCM), Engine Control Module (ECM), and Engine Computer are often used interchangeably for this component. It is the main computer that controls the engine and transmission functions.
What happens if I don’t replace a failing PCM?
Continuing to drive with a faulty PCM can lead to more severe issues, including catalytic converter damage from an incorrect air/fuel mixture, transmission damage from improper shifting, and leaving you stranded with a no-start condition.