Is Your GM Truck or Van Running Rough?
If your late-90s Chevrolet, GMC, or Cadillac is suffering from perplexing issues like stalling, poor fuel economy, erratic shifting, or a persistent Check Engine Light, the culprit is often the very brain of your vehicle: the Powertrain Control Module (PCM). This vital component manages everything from fuel injection and ignition timing to transmission shift points. When it fails, it can cause a cascade of problems that are frustrating to diagnose and can leave you stranded. Don’t let a faulty computer dictate your vehicle’s reliability. This is your direct-fit, fully programmed solution.
From the Diagnostic Bay
We had a 1999 Chevy Tahoe come in that was driving the owner crazy. It would start and run fine for 15 minutes, then suddenly stall and refuse to restart for an hour. He’d replaced the fuel pump, ignition coil, and crank sensor with no luck. The scanner showed a few intermittent communication codes but nothing consistent. After checking all the wiring and grounds, we hooked up a scope to the PCM’s main outputs. We saw the injector and ignition signals simply drop out when the engine warmed up. A faulty driver inside the original PCM was failing under heat. We installed one of our VIN-programmed modules, performed the security relearn, and the Tahoe ran perfectly. It’s a classic case where shotgunning parts costs more time and money than correctly identifying the root cause—a failing PCM.
Common Symptoms of a Failing GM PCM
- ✔ Check Engine Light is on with various communication or sensor codes (e.g., U-codes, P0601-P0606).
- ✔ Engine cranks but refuses to start, or starts and immediately stalls.
- ✔ Noticeable decrease in fuel efficiency for no apparent reason.
- ✔ The transmission shifts harshly, at the wrong times, or not at all.
- ✔ Unexplained engine stumbling, misfiring, or hesitation during acceleration.
- ✔ Intermittent issues that seem to appear and disappear, often related to engine temperature.
- ✔ Failure to pass an emissions test due to readiness monitor issues.
Your Trusted Source for a 1998-1999 Express 3500 PCM
This isn’t just a used part pulled from a salvage yard. This is a complete, ready-to-install solution. We take a genuine, tested OEM PCM and flash it with the latest official GM software calibration specifically for your vehicle. By providing us with your Vehicle Identification Number (VIN) during checkout, you ensure that the module you receive is perfectly matched to your engine, transmission, and factory options. This eliminates the need for an expensive trip to the dealership for programming, saving you hundreds of dollars and significant downtime.
The VIN Programming Advantage
Your vehicle’s VIN is the key to its identity. It tells the PCM about the engine size (4.3L, 5.0L, 5.7L), transmission type, gear ratios, and even tire size. Our process ensures all these parameters are correctly loaded, so your vehicle operates exactly as the manufacturer intended. This pre-programming makes the installation process as simple as possible. In most cases, after installation, you will only need to perform a simple security relearn procedure (often called a CASE relearn), which can typically be done without special tools. This synchronizes the new PCM with your vehicle’s anti-theft system.
Guaranteed Compatibility
This module, identified by part number 9355699, is a direct replacement for several other service numbers, including 16266645, 16250279, 16258815, and 09366810. It fits an extensive range of popular 1998 and 1999 GM models, including:
- Chevrolet & GMC Pickups (1500, 2500, 3500)
- Chevrolet Tahoe & GMC Yukon
- Chevrolet & GMC Suburban
- Express & Savana Vans (1500, 2500, 3500)
- Cadillac Escalade
- S10, S15, Sonoma, Blazer, and Jimmy with the 4.3L V6
- And many more.
Restore the performance and reliability of your truck or van with a dependable, correctly programmed 1998-1999 Express 3500 PCM that is ready for installation right out of the box.
Frequently Asked Questions
Do I need to get this PCM programmed?
No. This PCM comes fully pre-programmed to your vehicle’s specific VIN. You must provide your VIN at the time of purchase so we can load the correct GM software before shipping it to you.
Is this a simple plug-and-play installation?
It is very close to plug-and-play. After you physically install the module, you will likely need to perform a security relearn procedure. This allows the PCM to communicate with your vehicle’s anti-theft system. This procedure can usually be done without special scan tools and instructions are widely available online.
How do I find my original part number?
Your original part number is printed on a sticker on the PCM itself. The module is typically located in the engine bay, often on the driver’s side fender or near the battery. Match the number on your old unit to 9355699 or one of the compatible numbers listed in the description.
Where do I find my vehicle’s VIN?
Your 17-digit VIN can be found on a metal plate on the driver’s side of the dashboard (visible through the windshield), on the driver’s side door jamb sticker, or on your vehicle’s registration and insurance documents.
Is this a new part?
This is a high-quality, used OEM part that has been sourced from a salvaged vehicle. It is inspected, tested, and then programmed with the latest software for your vehicle, offering OEM reliability at a great value.