Is Your GM Truck or Van Acting Possessed?
If your 1998-1999 GMC 3500 is suddenly stalling, shifting erratically, or throwing a Christmas tree of seemingly unrelated check engine light codes, the problem might not be a dozen different sensorsโit could be the one component that controls them all: the Powertrain Control Module (PCM). Over my 20 years in the shop, I’ve seen countless hours and dollars wasted on replacing perfectly good parts when the vehicle’s computer was the real culprit. These PCMs, especially from this era, are known to fail, causing symptoms that can send even experienced mechanics on a wild goose chase.
From the Shop Floor: A Real-World Diagnosis
“A customer’s ’99 Chevy Suburban came in last week with a complaint of a harsh 1-2 shift and a random no-start condition that would happen once or twice a week. The codes were all over the placeโTPS sensor, MAF sensor, even a transmission solenoid code. After confirming the wiring harness and grounds were solid (a critical first step!), we connected a scan tool and saw the live data stream was dropping out intermittently. That’s a classic sign of a failing computer. We installed a VIN-programmed PCM just like this one, and the truck has been running perfectly ever since. It saved the customer from buying hundreds of dollars in unnecessary sensors.”
The Direct Solution: A Pre-Programmed, Tested OEM PCM
This isn’t just a part in a box; it’s a complete solution. We’ve taken a genuine, used OEM PCM, rigorously tested it to ensure full functionality, and we program it specifically for your vehicle using your VIN. This process installs the latest, most stable software updates from General Motors, addressing many of the common drivability issues these trucks and vans developed over the years. You get a reliable part that’s ready to install right out of the box.
- โ VIN-Programmed for You: We flash the module with your vehicle’s specific calibration. No expensive trips to the dealer for programming.
- โ Solves Common Issues: Corrects problems like rough idle, poor fuel economy, check engine lights, and transmission shifting faults.
- โ Latest GM Software: Ensures your engine and transmission operate with the most current and efficient logic.
- โ Cost-Effective Repair: Get the performance of an OEM part without the high cost of a new-from-dealer module.
- โ Broad Compatibility: This module, identified by service ID 9355699, fits a wide range of GM trucks and vans from 1998-1999.
Plug-and-Play Installation: Get Back on the Road Fast
Installing this PCM is a straightforward job you can do in your own driveway. While a security relearn procedure may be required on some models (a simple process you can find online), the core installation takes less than an hour.
- Safety First: Disconnect the negative battery terminal and wait a few minutes for the system to discharge.
- Locate the PCM: On most trucks and vans like the GMC 3500, the PCM is located in the engine compartment, typically on the driver’s side inner fender.
- Disconnect Connectors: Carefully unclip the wiring harness connectors from the old module. Inspect the pins for any corrosion or damage before proceeding.
- Remove Old Module: Unbolt the old PCM from its mounting bracket.
- Install New Module: Bolt the new, programmed PCM into place and securely reconnect the wiring harnesses.
- Final Steps: Reconnect the negative battery terminal. If your vehicle doesn’t start, perform the security relearn procedure (often called a VATS or Passlock relearn).
Confirming Your Fitment
This PCM is a direct replacement for part numbers 09355699, 16266645, 16250279, 16258815, and 9366810. It fits a huge variety of vehicles, including the Chevy/GMC 1500/2500/3500 pickups, Suburban, Tahoe, Yukon, Express/Savana vans, and more. The most important step is to provide us with your 17-digit VIN when you check out. This allows us to guarantee perfect compatibility and programming for your exact vehicle configuration.