Is Your Workhorse Truck Sidelined?
There’s nothing more frustrating than when your dependable 1998-1999 GMC 3500 suddenly won’t start, runs rough, or has its check engine light glaring at you from the dash. These classic trucks are built to last, but after two decades of service, their electronic components can start to fail. The Powertrain Control Module (PCM), the vehicle’s main computer, is often the culprit behind these baffling issues. It controls everything from fuel injection and spark timing to transmission shifting, and when it goes, the whole system suffers.
Over my 20 years on the shop floor, I’ve seen countless GMT400 platform trucks and vans with symptoms that stumped their owners. A customer’s ’99 Chevy 3500 dually came into my shop last month with an intermittent no-start and a random stalling problem. We checked all the basics—fuel pressure was good, the crank sensor was new—but the problem persisted. After hooking up the scope, we found the PCM was intermittently failing to send a signal to the ignition control module. This is a classic internal failure I’ve diagnosed on dozens of these exact PCMs. Replacing it with a reliable, correctly programmed unit brought that truck right back to life.
The Direct Solution for Your 1998-1999 GMC 3500 PCM
This isn’t just a used part pulled from a yard; it’s a complete, ready-to-install solution. We take a genuine, tested OEM computer and program it specifically for your truck using your Vehicle Identification Number (VIN). This process ensures all factory settings are correct and loads the latest available software updates from General Motors, often improving performance and drivability over the original programming.
- ✔ Fix Common Issues: A direct solution for no-start conditions, rough idle, poor fuel economy, erratic shifting, and false sensor codes.
- ✔ VIN Programmed: We flash the module with your truck’s specific VIN, ensuring perfect communication with your vehicle’s systems.
- ✔ Plug-and-Play: Arrives ready for installation. No expensive trip to the dealership for programming is required.
- ✔ Cost-Effective Repair: Get your truck running right without the high cost of a new-from-dealer computer.
- ✔ Broad Compatibility: This PCM is a direct replacement for multiple part numbers and fits a wide range of GM trucks, vans, and SUVs.
Plug-and-Play Installation: No Dealer Visit Required
You can get your truck back on the road in under an hour with basic hand tools. Follow these simple steps to swap your PCM.
- Safety First: Disconnect the negative terminal from your truck’s battery to prevent any electrical shorts.
- Locate the PCM: On most of these trucks and vans, the PCM is located in the engine compartment, typically on the driver’s side inner fender or near the battery.
- Disconnect the Connectors: Carefully unclip the wiring harness connectors from the old PCM. Inspect the pins and connectors for any corrosion or damage.
- Remove the Old Module: Unbolt the PCM from its mounting bracket.
- Install the New Module: Bolt your new, pre-programmed PCM into the bracket and securely reconnect the wiring harnesses. You should hear a ‘click’ as they lock in place.
- Reconnect the Battery: Reattach the negative battery terminal. Your truck is now ready to start.
Expert Pro Tip: Clean Your Connections
Before plugging in your new PCM, take a moment to spray the vehicle’s harness connectors with a quality electronics cleaner. Use a small, soft brush (like a toothbrush) to gently scrub away any dirt or light corrosion on the pins. This simple step ensures a clean, solid connection and can prevent a host of future communication errors. A poor connection is one of the most common reasons a good part fails to work correctly.
Guaranteed Fitment
This computer is a direct replacement for units with the service number 09355699. It also interchanges with the following part numbers:
16266645, 9355699, 16250279, 16258815, 09366810, 9366810
This module fits a wide variety of 1998-1999 GM models, including the Chevrolet/GMC C/K 1500, 2500, 3500 pickups, Suburban, Tahoe, Yukon, Express/Savana vans, and more. Please verify your original part number or use the fitment chart to confirm compatibility. Simply provide us with your VIN after purchase, and we’ll handle the rest.