Is Your 2003 GMC Savana 3500 Running Rough?
As the workhorse of your fleet or your personal project vehicle, a 2003 GMC Savana 3500 that isn’t running correctly is more than an inconvenience—it’s a major problem. If you’re dealing with a persistent Check Engine Light, erratic engine behavior, poor fuel economy, or even a no-start condition, the root cause is often a failing Powertrain Control Module (PCM). This module is the brain of your vehicle, controlling everything from fuel injection and spark timing to transmission shifting. When it fails, the symptoms can be confusing and frustrating.
This replacement Powertrain Control Module, part number 12576106, is the definitive solution to get your van back in service. We take the guesswork out of the repair by pre-programming the unit specifically for your vehicle. Simply provide us with your Vehicle Identification Number (VIN) after your purchase, and our technicians will flash the module with the latest, most stable software updates directly from GM. This ensures optimal performance, fuel efficiency, and reliability, essentially restoring the electronic brain of your vehicle to factory specifications.
From the Diagnostic Bay
We had a 2003 Express 3500 (a sister vehicle to the Savana) come into the shop with a bizarre issue. The owner complained of intermittent stalling at stoplights and a transmission that would randomly refuse to shift out of first gear. He’d already replaced the throttle body and a few sensors with no luck. We hooked up our scanner and saw communication errors with the PCM. After confirming the wiring harness was intact, we knew the module itself was the culprit. We installed a VIN-programmed unit just like this one, performed the security relearn, and the van ran perfectly. It’s a classic case of a failing computer causing phantom mechanical issues, and a properly programmed module is the only real fix.
Diagnosing a Faulty 2003 Savana 3500 Powertrain Module
A failing PCM can manifest in numerous ways, often mimicking other component failures. If you’re experiencing any of the following symptoms, your engine computer is a likely suspect. This module is the direct solution for these common problems.
- ✔ Check Engine Light: The light is on, and you may have codes related to module communication (U-codes), sensor circuits, or processor faults.
- ✔ No-Start Condition: The engine cranks but won’t start, often due to a lack of fuel injector pulse or spark command from the PCM.
- ✔ Poor Engine Performance: Noticeable loss of power, hesitation, stumbling, or rough idling.
- ✔ Reduced Fuel Economy: A sudden and unexplained drop in MPG is a common sign the PCM is not managing the engine efficiently.
- ✔ Erratic Shifting: The transmission may shift harshly, get stuck in a gear, or shift at the wrong times.
- ✔ Intermittent Stalling: The engine may stall for no apparent reason, either while driving or at an idle.
- ✔ Failed Emissions Test: Inability to pass smog or emissions testing due to PCM-related faults.
Plug-and-Play Installation Process
Our goal is to make this repair as straightforward as possible. By programming the module with your VIN, we handle the most complex part of the job before it even ships. When you receive your 2003 Savana 3500 Powertrain Module, the physical installation is simple. It is typically located in the LH rear of the engine compartment on the Savana vans. After installation, you may need to perform a security relearn procedure (often called a Passlock or VATS relearn), which pairs the new module to your vehicle’s anti-theft system. This procedure is simple and can be done without special tools, typically involving a series of key cycles. Instructions are widely available online for your specific model.
Broad GM Compatibility
While this is a perfect fit for the 2003 Savana 3500, this versatile P59 series PCM was used across a wide range of GM trucks, vans, and even some cars. It is a direct replacement for multiple service numbers including 12581565, 12570557, 12576869, and 89017733, among others. It fits vehicles like the Chevrolet Express, Silverado, Suburban, GMC Sierra, Yukon, and Cadillac CTS from the 2003-2004 era. Please verify the part number and check the compatibility list to ensure this is the correct module for your application.
Frequently Asked Questions
Do I need to do anything after installing this PCM?
Because this module is pre-programmed to your VIN, no dealer visit is required for flashing. However, you will likely need to perform a security relearn procedure. This typically takes about 30 minutes and involves a sequence of turning the key on and off. Some applications may also require a Crankshaft Variation Relearn (CASE relearn), which requires a capable scan tool.
How do I provide my VIN?
After you complete your purchase, please send us a message with your 17-digit Vehicle Identification Number (VIN). We cannot program and ship your module without it. The VIN is found on your driver’s side dashboard (viewable through the windshield) or on the driver’s door jamb sticker.
Is this a new or used part?
This is a high-quality, fully tested replacement part. Each unit undergoes rigorous inspection and functional testing to ensure it meets or exceeds original equipment performance. It is then programmed with the latest GM-certified software for your vehicle.
Will this fix my transmission shifting problems?
In many cases, yes. The PCM (Powertrain Control Module) controls both the engine and the transmission. If your shifting issues are caused by faulty electronic commands, this replacement 2003 Savana 3500 Powertrain Module is the correct solution. If the problem is internal to the transmission (e.g., a bad solenoid or clutch pack), this will not fix it.
What is the warranty on this module?
This part comes with our standard warranty against defects in materials and workmanship. Please see our store’s warranty page for full details and duration. We stand behind our products to ensure your complete satisfaction.