Is Your Chevy 3500 Running Rough, Stalling, or Not Starting?
As a mechanic with over two decades of experience under the hood, I’ve seen it all when it comes to the workhorse GMT400 platform. If your 1998-1999 truck or van is suddenly giving you headaches—like erratic idling, poor fuel economy, harsh shifting, or the dreaded crank-no-start—the problem often points directly to a failing Powertrain Control Module (PCM). This isn’t just a part; it’s the brain of your vehicle, and when it goes, it can create a host of confusing and frustrating symptoms.
From the Shop Floor: “A customer’s ’99 Chevy 3500 came in last week with these exact symptoms. It would crank all day but wouldn’t fire up, and the fuel pump was silent. The owner had already replaced the pump and relay, chasing his tail. After a quick check of the power and ground circuits at the module connectors, my scan tool confirmed the real issue: no communication with the PCM. It was internally fried, a common failure I’ve diagnosed on hundreds of these GM trucks. We swapped in a programmed module like this one, and it fired up on the first turn of the key.”
The Direct Solution: A VIN-Programmed PCM Ready to Install
Don’t waste time and money at the dealership. This is a reliable, tested PCM sourced from a salvaged vehicle that we program specifically for your truck. When you order, you provide us with your Vehicle Identification Number (VIN). We then flash the module with the latest official GM software updates for that specific VIN. This process corrects common factory bugs and ensures your vehicle’s systems communicate perfectly, restoring performance and reliability.
Common Symptoms of a Failing PCM:
- ✔ Check Engine Light is on with various communication codes
- ✔ Engine stalls randomly while driving or at idle
- ✔ Vehicle cranks but refuses to start
- ✔ Noticeable drop in fuel mileage
- ✔ Automatic transmission shifts harshly or erratically
- ✔ No power to the fuel pump
Easy Installation for the DIY Mechanic
Replacing your 1998-1999 Chevrolet 3500 PCM is a straightforward job you can do in your own driveway. Because we program it beforehand, you won’t need a trip to the dealer or any specialized scan tools for setup.
- Safety First: Disconnect the negative terminal from your vehicle’s battery.
- Locate the PCM: On most of these trucks and vans, the PCM is located in the engine compartment, typically on the driver’s side fender or near the battery.
- Disconnect the Harnesses: Carefully unclip the wiring harness connectors from the old module. Inspect the pins and connectors for any corrosion or damage and clean them if necessary.
- Swap the Modules: Unbolt the old PCM and secure the new one in its place.
- Reconnect Everything: Firmly plug the wiring harnesses into your new PCM until they click into place. Reconnect the negative battery terminal.
- Start the Engine: Your vehicle is now ready to run with its newly programmed brain.
Guaranteed Compatibility and Part Number Information
This module is a direct replacement for several original part numbers, ensuring a perfect fit and function for a wide range of GM vehicles. This unit, identified by service number 09355699, also replaces the following part numbers: 16266645, 9355699, 16250279, 16258815, 09366810, and 9366810.
It is compatible with many 1998 and 1999 Chevrolet, GMC, Cadillac, Oldsmobile, and Isuzu models including the Silverado, Sierra, Suburban, Tahoe, Yukon, Express, Savana, and more. Please verify your original part number or consult the detailed fitment list to confirm this is the correct part for your specific vehicle and engine combination.