Is your GMC 3500 pickup suffering from erratic shifting, poor fuel economy, or a persistent Check Engine Light? These are classic signs of a failing Powertrain Control Module (PCM), the central computer that manages your truck’s engine and transmission. A faulty PCM can lead to a cascade of frustrating issues, leaving your reliable workhorse parked on the sidelines. This replacement PCM, part number 16263494, is the definitive solution to restore your vehicle’s performance, drivability, and reliability.
Unlike generic modules that require expensive trips to the dealership for programming, this unit arrives at your door ready for installation. We take your vehicle’s unique Vehicle Identification Number (VIN) and flash the module with the latest, most stable software updates directly from GM. This ensures perfect communication between all vehicle systems, just as the manufacturer intended. By handling the programming beforehand, we eliminate the guesswork and extra cost, providing a true plug-and-play repair.
Diagnosing a Faulty 1999-2000 GMC 3500 PCM
The PCM is the brain of your vehicle’s powertrain. When it begins to fail, the symptoms can be widespread and confusing. If you’re experiencing any of the following issues, your PCM is the most likely culprit. This module is the correct, VIN-programmed solution for your 1999-2000 GMC 3500 PCM and many other GM vehicles of the era.
Common Symptoms of PCM Failure
- ✔ Check Engine Light: The module may set false trouble codes (DTCs) for sensors that are actually working correctly, or it may fail to communicate with a diagnostic scan tool altogether.
- ✔ Engine Performance Problems: You might notice rough idling, stalling, hesitation during acceleration, engine misfires, or a significant drop in fuel efficiency.
- ✔ Transmission Shifting Issues: The PCM also controls the transmission. Failure can result in harsh shifting, delayed engagement into gear, or getting stuck in one gear (limp mode).
- ✔ No-Start Condition: In severe cases, a complete PCM failure can prevent the engine from starting at all, even if the battery and starter are good. It may fail to command the fuel pump or ignition system to operate.
- ✔ Failed Emissions Test: A malfunctioning PCM can’t properly manage the fuel and emissions systems, leading to an automatic failure at the inspection station.
Replacing your failing module with this pre-programmed unit is the most effective way to resolve these issues and get your truck back to work. We ensure it’s loaded with the correct software for your specific engine, transmission, and emissions equipment based on your VIN.
This module is a direct replacement for several part numbers, including 16263494, 16265035, 8162634940, 218-11787, and 21811787. It fits a wide array of GM trucks and vans, such as the Chevrolet Silverado, Express, Tahoe, Suburban, S10, Blazer, and the GMC Sierra, Savana, Yukon, and Sonoma. Please verify the part number or consult the detailed fitment list to confirm compatibility with your exact vehicle.
Frequently Asked Questions
Do I need to get this PCM programmed?
No. This is the biggest benefit of our service. You provide us with your vehicle’s VIN during checkout, and we program the module with the latest GM software before it ships. It arrives ready to install.
Where is the PCM located on my 1999-2000 GMC 3500?
On most GMC and Chevrolet pickups from this era, the PCM is located in the engine compartment on the driver’s side, often near the battery or firewall. It’s a silver metal box with multiple large electrical connectors.
What happens if I install this without providing a VIN?
The module will not function correctly. The programming is specific to your vehicle’s engine, transmission, and options. Without the correct VIN-based software, your truck may not start or will run very poorly. We cannot ship the part until we receive your VIN.
Is any other procedure needed after installation?
In many cases, you may need to perform a security relearn procedure, which can often be done without special tools. Some vehicles may also require a Crankshaft Variation Relearn (CASE Relearn) to clear a P1336 trouble code, which requires a capable scan tool.
Is this a new or used part?
This is a professionally serviced, original equipment (OEM) part that has been tested, inspected, and prepared to meet or exceed original factory specifications. It is flashed with the most current software for your vehicle.