Is your 1998 or 1999 Chevrolet 3500, or another GM truck from that era, running rough, stalling, or showing a persistent check engine light? These are classic signs of a failing Powertrain Control Module (PCM). The PCM is the brain of your vehicle’s engine, managing everything from fuel mixture and ignition timing to transmission shifting. When it fails, it can cause a wide range of frustrating and difficult-to-diagnose issues. This pre-programmed PCM is the most straightforward and reliable solution to get your workhorse back on the road.
From the Diagnostic Bay
I remember a customer with a ’99 Suburban who had spent nearly a thousand dollars chasing a ghost. His truck would randomly stall at stoplights and had a rough idle. He had replaced the spark plugs, ignition coil, and even the fuel pump based on advice from forums. When he finally brought it to our shop, we connected the scanner and saw erratic data from multiple sensors. An experienced technician knows that when multiple, unrelated sensors act up at once, the problem isn’t the sensors—it’s the computer reading them. We swapped in a correctly programmed PCM, and the truck ran like it just rolled off the assembly line. This simple replacement saved him from more wasted time and money.
Common Symptoms of a Failing PCM
- ✔ Check Engine Light is on with various, often inconsistent, error codes.
- ✔ Engine stalling or shutting off unexpectedly while driving.
- ✔ Difficulty starting the engine or a complete no-start condition.
- ✔ Poor engine performance, hesitation, or misfires.
- ✔ Reduced fuel economy for no apparent reason.
- ✔ Harsh or erratic automatic transmission shifting.
- ✔ Failure to pass state emissions testing.
The Direct-Fit Solution for Your GM Truck or Van
Finding a replacement computer for these classic GM vehicles can be a challenge, and getting one programmed is another hurdle. We’ve eliminated the guesswork. This is a genuine, used OEM PCM sourced from a salvaged vehicle, ensuring original factory performance and durability. Before we ship it, our technicians program it using your vehicle’s specific Vehicle Identification Number (VIN). This process loads the latest GM-authorized software and calibrations directly onto the module, making it ready for installation right out of the box. This is a crucial step that ensures all components of your 1998-1999 Chevrolet 3500 PCM communicate correctly.
After installation, the only remaining step is a simple security relearn procedure (often called VATS or Passlock), which can be done in your driveway with just the key. This procedure syncs the new computer with your vehicle’s anti-theft system. Once completed, your engine will start and run as it should, with its performance and reliability restored.
Guaranteed Compatibility
This module, part number 9366810, is a direct replacement for several other service numbers, including 09355699, 16266645, and 16250279. It is compatible with a wide array of 1998-1999 GM trucks and vans, such as the Chevrolet and GMC Pickups (1500, 2500, 3500), Suburban, Tahoe, Yukon, Express, and Savana vans, as well as the Cadillac Escalade, Oldsmobile Bravada, and more. Please verify your original part number or consult the detailed fitment list to confirm this is the correct part for your vehicle.
Frequently Asked Questions
Do I need to have this PCM programmed?
No. We handle the programming for you before shipment. Simply provide us with your vehicle’s VIN during or after checkout, and we will flash the module with the correct software for your specific vehicle. It will arrive ready to be installed.
What is a security relearn procedure?
The security relearn, or VATS/Passlock relearn, is a simple process that syncs the replacement PCM to your vehicle’s anti-theft system. It typically involves turning the key to the ‘ON’ position for 10-15 minutes, then ‘OFF’, and repeating this cycle three times. No special tools are required, and instructions are readily available online for your specific model.
Is this a new part?
This is a high-quality, tested, and fully functional used OEM part recovered from a salvaged vehicle. We inspect and guarantee its performance. Using a genuine OEM computer ensures the best compatibility and longevity compared to aftermarket alternatives.
How do I find my original part number?
Your vehicle’s original PCM part number is printed on a sticker on the module itself. On most GM trucks and vans of this era, the PCM is located in the engine bay, often on the driver’s side fender or near the battery.
Will this fix my vehicle’s problem?
If your vehicle is exhibiting multiple symptoms listed above and a professional diagnosis has pointed to a faulty computer, this part is very likely the solution. A faulty PCM can mimic many other component failures, so proper diagnosis is always recommended.