Restore Peak Performance to Your Truck
Is your 1999 or 2000 GMC Sierra 1500 suffering from baffling electrical gremlins, poor engine performance, or erratic shifting? The Powertrain Control Module (PCM) is the central computer of your vehicle, orchestrating critical engine and transmission functions. When it begins to fail, it can cause a wide range of frustrating and difficult-to-diagnose issues. This direct-fit replacement PCM is the definitive solution to get your truck back on the road, running as it should. We eliminate the guesswork and costly dealership visits by pre-programming this module specifically for your truck using your Vehicle Identification Number (VIN). This ensures that all factory settings for your engine, transmission, and accessories are perfectly matched, providing a seamless installation and immediate restoration of function.
The Brains Behind Your Powertrain: The 1999-2000 Sierra 1500 PCM
The PCM in your GMT800 platform truck is a sophisticated computer responsible for managing fuel delivery, ignition timing, emissions systems, and automatic transmission shift points. It constantly analyzes data from dozens of sensors throughout the vehicle to make real-time adjustments for optimal power, efficiency, and smoothness. Over time, heat cycles, vibrations, and electrical stress can cause internal components to degrade, leading to intermittent or complete failure. Replacing a faulty module with a correctly programmed unit is essential for your truck’s health and reliability.
Common Symptoms of a Failing PCM
- ✔ Persistent Check Engine Light (CEL) with communication-related codes (e.g., U-codes) or multiple, unrelated sensor codes.
- ✔ Engine performance issues such as stalling, hesitation, misfiring, or rough idling.
- ✔ Erratic or harsh automatic transmission shifting, or getting stuck in one gear.
- ✔ A sudden, unexplained drop in fuel economy.
- ✔ Complete no-start condition where the engine cranks but will not fire up.
- ✔ Failure of emissions-related components to pass inspection.
Plug-and-Play Solution with VIN Programming
Don’t settle for a generic, off-the-shelf module that requires an expensive trip to the dealer for programming. We take care of the critical programming step for you. After your purchase, simply provide us with your truck’s 17-digit VIN. Our technicians will flash the module with the latest GM-certified software specific to your vehicle’s configuration. This ensures it communicates perfectly with all other modules and sensors right out of the box. While the unit is plug-and-play, some vehicles may require a Crankshaft Variation Relearn (also known as a CASE relearn) using a compatible scan tool to prevent a P1336 trouble code. This is a simple procedure for any qualified mechanic.
This module is a direct replacement for part numbers: 16263494, 16265035, 8162634940, 218-11787, 21811787. Please verify your part number before ordering to ensure compatibility.
Frequently Asked Questions
Why do you need my VIN?
Your vehicle’s VIN (Vehicle Identification Number) allows us to program the PCM with the exact software and calibrations for your specific engine, transmission, and factory options. This ensures a perfect match and proper function without needing a trip to the dealership.
Is this part difficult to install?
Installation is straightforward for someone with basic mechanical skills. It typically involves disconnecting the battery, unplugging the electrical connectors from the old PCM, unbolting it from its bracket, and then installing the new one in reverse order. The entire process usually takes less than 30 minutes.
What is a CASE Relearn and will I need to perform one?
A CASE (Crankshaft Angle Sensor Error) Relearn is a procedure that synchronizes the new PCM with the crankshaft position sensor. Some vehicles may require this after installation to prevent a P1336 code. It must be done with a professional-grade bidirectional scan tool and is a common procedure for any repair shop.
How can I be sure my old PCM is the problem?
Diagnosing a PCM requires ruling out other potential causes first, such as faulty sensors, wiring issues, or poor battery connections. If all other related components have been tested and are working correctly, and you are experiencing multiple, intermittent electronic symptoms, the PCM is the most likely culprit.
Will this module work for other GM trucks and vans?
Yes, this PCM is compatible with a wide range of GM vehicles from the late 90s and early 2000s that use part number 16263494, including various Silverado, Express, Savana, S10, and Blazer models. Please check the detailed fitment list on this page to confirm it fits your specific vehicle.