Is Your GM Truck or Van Running Rough? The PCM Might Be the Culprit.
The Powertrain Control Module, or PCM, is the central computer of your 1998-1999 GMC Savana 2500. It’s the brain behind the entire operation, managing everything from fuel injection and ignition timing to transmission shift points and emissions controls. When this critical component begins to fail, it can cause a cascade of confusing and frustrating problems that can be difficult to diagnose. From a simple check engine light to a vehicle that won’t start at all, a faulty PCM can leave you stranded and facing a costly repair bill at the dealership.
From the Diagnostic Bay
We once had a 1999 Chevy Express van come in that the owner swore had a bad transmission. It was shifting hard and sometimes wouldn’t shift out of first gear at all. He had already replaced the vehicle speed sensor and the transmission solenoids with no luck. After hooking up our professional scan tool, we noticed that while the sensors were sending good data, the PCM wasn’t correctly interpreting the signals to command shifts. The internal logic had failed. Instead of a multi-thousand dollar transmission rebuild, the fix was this exact type of programmed PCM. We flashed it to the van’s VIN, performed a quick security relearn, and the van was shifting perfectly again. It’s a classic case of symptoms in one area being caused by a failure in the electronic brain.
Common Symptoms of a Failing PCM
If your vehicle is experiencing any of the following issues, a failing PCM could be the root cause. Proper diagnosis is always recommended, but these are strong indicators that the main computer is at fault:
- ✔ Persistent Check Engine Light (CEL) that won’t clear, especially with communication-related error codes (e.g., U-codes).
- ✔ Engine stalling intermittently or refusing to start, even though it cranks over.
- ✔ Noticeable decrease in fuel efficiency for no apparent reason.
- ✔ Rough idling, engine misfires, or hesitation during acceleration.
- ✔ Harsh, erratic, or delayed automatic transmission shifting.
- ✔ Failure to pass an emissions test due to monitor readiness issues.
- ✔ In some cases, multiple unrelated warning lights may appear on the dashboard as the PCM loses communication with other modules.
The Direct-Fit Solution: Your Pre-Programmed 1998-1999 Savana 2500 PCM
Don’t let a faulty computer keep your reliable GM truck or van off the road. This is a genuine, used OEM Powertrain Control Module that has been thoroughly tested and is ready for installation. The key to our service is the pre-programming. When you place your order, you provide us with your vehicle’s unique 17-digit Vehicle Identification Number (VIN). Our technicians then use official GM software to load the latest, most updated calibration specifically for your vehicle’s engine, transmission, and factory options. This ensures seamless integration and performance, eliminating the need for an expensive trip to the dealership for programming.
This module is a direct replacement for multiple service numbers, including 09355699, 16266645, 9355699, 16250279, 16258815, 09366810, and 9366810. By programming to your VIN, we ensure this single part works perfectly across a wide range of compatible vehicles.
Installation and Next Steps
Installing the PCM is a straightforward process for a DIY mechanic or any professional technician. Always disconnect the negative battery terminal before beginning. The module is typically located in the engine bay. Once the new module is connected and the battery is reconnected, you will likely need to perform a security relearn procedure (often called a Passlock or VATS relearn). This procedure syncs the new PCM with your vehicle’s anti-theft system and can usually be done without special tools. A quick search for your specific model’s ‘security relearn procedure’ will provide the simple steps required.
Frequently Asked Questions
Do I need to get this programmed by a dealer after I receive it?
No. The main benefit of our service is that we program the module to your vehicle’s specific VIN before we ship it. This makes the installation process much simpler and avoids extra costs at a dealership or repair shop.
How do I provide my VIN?
After you complete your purchase, we will send you a message requesting your 17-digit VIN. You can also add it as a note during checkout. We cannot ship the module until we have your VIN to program it correctly.
Is this a new part?
This is a high-quality, tested, and fully functional used OEM part sourced from a salvaged vehicle. Using a genuine OEM part ensures perfect fitment and compatibility, which can be an issue with aftermarket alternatives.
My original part number is 09355699, not 16250279. Will this work?
Yes. This module is compatible with all the part numbers listed in the description. Since we flash the software based on your VIN, it will function identically to the original module, regardless of the number printed on the case.
What is a security relearn procedure?
It’s a simple procedure that syncs the new PCM to your vehicle’s anti-theft system, allowing it to start. It typically involves turning the key to the ‘ON’ position for 10-15 minutes, then off, and repeating the cycle three times. Specific instructions for your vehicle can be easily found online.