Is Your GM Truck or Van Running Rough?
If you’re dealing with frustrating issues like a persistent check engine light, poor fuel economy, erratic shifting, or even a no-start condition in your 1998-1999 GM vehicle, a failing Powertrain Control Module (PCM) is often the culprit. The PCM is the brain of your vehicle, controlling everything from the fuel injectors and ignition timing to the transmission shift points. When it starts to fail, it can cause a cascade of problems that are difficult to diagnose and can sideline your reliable workhorse.
Common Symptoms of a Failing PCM:
- ✔ Check Engine Light is on with various trouble codes (DTCs).
- ✔ Engine stalling, stumbling, or misfiring.
- ✔ Harsh or unpredictable automatic transmission shifting.
- ✔ A noticeable drop in fuel mileage.
- ✔ The engine cranks but refuses to start.
- ✔ Failure to pass an emissions test.
- ✔ Communication errors with diagnostic scan tools.
The Direct-Fit Solution: A VIN-Programmed 1998-1999 GMC 2500 PCM
Don’t let a faulty computer keep you off the road. This is a dependable, genuine used Powertrain Control Module (service number 9355699) that serves as a direct replacement for a wide range of 1998-1999 Chevrolet and GMC trucks, vans, and SUVs. The critical difference with our service is that we program the module specifically to your vehicle’s Vehicle Identification Number (VIN) before it ships. This ensures that it has the correct factory calibration and the latest GM software updates for optimal performance, fuel efficiency, and emissions control. This process eliminates the need for an expensive trip to the dealership for programming.
From the Diagnostic Bay
We had a ’99 Chevy Suburban come in that the owner had thrown hundreds of dollars at. He’d replaced the spark plugs, wires, cap, rotor, and even the fuel pump trying to chase down an intermittent misfire and stalling issue. The codes were all over the place. After checking all the basics, we hooked up a scope to the injector drivers and saw the signals were dropping out randomly. The root cause wasn’t any of the parts he’d replaced; it was a failing driver inside the original PCM. We installed a VIN-programmed unit just like this one, performed the security relearn, and the truck ran like it just rolled off the assembly line. It’s a classic case of diagnosing the brain, not just the symptoms.
Simple Installation Process
Replacing the PCM is a straightforward job for a DIY mechanic with basic tools. It’s typically located in the engine compartment. After disconnecting the battery, you simply unbolt the old module, disconnect the wiring harnesses, and install the new one in its place. Once installed, you will likely need to perform a simple security relearn procedure (often called a Passlock or VATS relearn), which pairs the new computer to your vehicle’s anti-theft system. This procedure can usually be done without special tools and instructions are widely available online or in service manuals.
This unit is a tested, functional component sourced from a salvaged vehicle, providing a cost-effective and reliable alternative to searching for a new, often unavailable, part. By providing us with your VIN upon purchase, you guarantee that the 1998-1999 GMC 2500 PCM you receive is ready to restore your vehicle’s proper function.
Frequently Asked Questions
Is this part ready to install out of the box?
Yes, this PCM is programmed to your vehicle’s VIN before we ship it. However, you will most likely need to perform a security relearn procedure after installation to sync the computer with your vehicle’s anti-theft system. This procedure typically takes 10-30 minutes and does not require special tools.
How do I provide my VIN?
After you complete your purchase, we will contact you for your vehicle’s 17-digit VIN. We cannot ship the module until we have this information to program it correctly.
My original part number isn’t 9355699, will this still work?
This module is compatible with several part numbers, including 09355699, 16266645, 16250279, 16258815, 09366810, and 9366810. Please check the extensive fitment list on this page to confirm it fits your specific make, model, and engine.
Is this a new computer?
No, this is a genuine, used OEM part that has been sourced from a salvaged vehicle. Each unit is inspected to ensure it is in good working condition before being programmed and shipped.
What if I have issues after installation?
First, ensure the security relearn procedure was completed successfully. If problems persist, double-check all electrical connections. A failing sensor or wiring issue elsewhere on the vehicle can sometimes mimic PCM failure. We are here to help with diagnostic advice if you run into trouble.