Restore Peak Performance to Your GM Truck or Van
Is your 1999-2000 GMC Sierra 1500, or another compatible GM vehicle, suffering from frustrating and unpredictable engine problems? A faulty Powertrain Control Module (PCM) is often the culprit behind issues that can leave you stranded. As the electronic brain of your vehicle, the PCM governs everything from fuel mixture and ignition timing to transmission shift points. When it fails, performance, reliability, and fuel economy suffer. This replacement 1999-2000 Sierra 1500 PCM is the definitive solution, arriving at your door programmed with the latest GM software updates specifically for your vehicle’s VIN.
A Technician’s Notebook
I remember a 2000 GMC Sierra 1500 with the 4.3L V6 that came into my shop with a maddeningly intermittent no-start condition. It would run perfectly for days, then refuse to start after being driven and sitting for about an hour. The owner had already replaced the fuel pump and ignition coil. All the basics checked out, but there were no trouble codes stored. On a hunch, I monitored the PCM data stream during a hot-soak period. Sure enough, as the engine bay heat built up, the PCM would stop communicating. This is a classic sign of internal circuit board failure on these units. We installed a VIN-programmed module just like this one, and the truck has been starting reliably ever since. It’s a fix I’ve performed hundreds of times on these GM platforms.
Is Your Truck Showing These Warning Signs?
A failing PCM can manifest in numerous ways. If you’re experiencing any of the following, it’s a strong indicator that your module needs attention:
- ✔ Unexplained Check Engine Light (CEL), especially with codes like P0601 (Internal Control Module Memory Check Sum Error) or P0606 (PCM Processor Fault).
- ✔ Engine stalling or shutting off while driving.
- ✔ Harsh or erratic automatic transmission shifting.
- ✔ A noticeable drop in fuel economy.
- ✔ The engine cranks but refuses to start.
- ✔ Communication errors with diagnostic scan tools.
A Straightforward Guide to Installation
Replacing the PCM is a job most DIY mechanics can handle. Our pre-programming service eliminates the most difficult step, saving you a trip to the dealership. Follow these general steps for a successful installation:
- Safety First: Always disconnect the negative terminal from your vehicle’s battery before starting any electrical work.
- Locate the PCM: On most 1999-2000 Sierra/Silverado models with a 6-cylinder engine, the PCM is located in the engine compartment on the driver’s side, often under or near the battery tray. For vans and other models, refer to your service manual for the exact location (e.g., LH rear engine compartment).
- Disconnect the Connectors: Carefully unclip and remove the electrical wiring harness connectors from the old PCM. These connectors have locking tabs that need to be released before they can be pulled away.
- Remove the Old Module: Unbolt the PCM from its mounting bracket. Keep the hardware, as you will need it to install the new unit.
- Install the New PCM: Mount your new, pre-programmed PCM onto the bracket and secure it with the original hardware.
- Reconnect Everything: Firmly plug the wiring harness connectors into the new module until they click into place. Reconnect the negative battery terminal.
- Security Relearn & Final Checks: In many cases, you may need to perform a security relearn procedure (often called a Passlock relearn) for the vehicle to start. A Crankshaft Variation (CASE) relearn with a capable scan tool is also recommended for optimal performance, though the vehicle will typically run without it.
Verified Vehicle Compatibility
This module is a direct replacement for service number 16263494 and part number 218-11787. It is guaranteed to fit a wide range of GM vehicles. Please verify your vehicle is on this list and provide your VIN upon purchase for correct programming.
This part fits many models including the 1999-2000 GMC Sierra 1500 (6-cyl), Silverado 1500 (6-cyl), Chevrolet/GMC 2500/3500 Pickups (gas), Tahoe, Yukon, Suburban, Escalade, S10/Sonoma (4.3L), Blazer/Jimmy (4.3L), Astro/Safari, and Express/Savana vans. Please refer to the detailed fitment list to confirm compatibility with your specific year and engine options.
Frequently Asked Questions
Why do you need my VIN?
Your Vehicle Identification Number (VIN) is essential for us to program the PCM with the correct software for your truck’s specific engine, transmission, and factory options. This ensures seamless integration and proper function, just like a part from the dealership.
Is this a simple plug-and-play installation?
For the most part, yes. The module is pre-programmed, so you won’t need a dealer’s scan tool for that step. However, some GM vehicles require a security relearn procedure after installation, which can typically be done without special tools. A CASE relearn is also recommended for best performance.
Will this fix my Check Engine Light?
If the Check Engine Light is on due to an internal PCM failure (like code P0601), this replacement module will solve the problem. However, if the light is on for another reason (e.g., a bad oxygen sensor), you will still need to address that separate issue.
What if my original part number is slightly different?
This module is compatible with several part numbers, including 16263494, 16265035, and 8162634940. As long as your vehicle is on the compatibility list, our VIN-based programming will ensure it works correctly, even if the number on your old part differs.
What is a CASE relearn?
A Crankshaft Position System Variation (CASE) relearn is a procedure that calibrates the PCM to the minor imperfections of your engine’s crankshaft sensor reluctor wheel. While the truck will usually run fine without it, performing this procedure with a capable scan tool can prevent a P1336 trouble code and ensure the most accurate misfire detection.