Restore Your Truck’s Brain and Brawn
Is your trusty 1999-2000 Silverado 1500, or another GM truck or van, giving you headaches? Unexplained stalling, a stubborn check engine light, or rough, unpredictable performance can be incredibly frustrating. As a mechanic with over two decades of experience, I’ve seen these symptoms countless times. More often than not, the culprit is a failing Powertrain Control Module (PCM)—the central computer that manages everything from fuel mixture to transmission shifting.
This isn’t just a replacement part; it’s a complete, ready-to-install solution. We take the guesswork and dealer hassle out of the equation. By providing us with your vehicle’s VIN at checkout, you’ll receive a PCM that is professionally flashed with the latest, most stable software updates directly from GM. This ensures optimal performance, fuel efficiency, and reliability, essentially giving your vehicle’s computer a fresh start. This 1999-2000 Silverado 1500 PCM is your direct path to resolving those phantom electrical issues and getting your dependable workhorse back on the road.
From the Diagnostic Bay: The Ghost in the Machine
I once had a 2000 GMC Sierra in the shop with a problem that was driving the owner crazy. It would randomly stall at red lights, but only when the A/C was on. No consistent codes, just pure frustration. We checked the fuel pressure, alternator, and idle air control valve—all were fine. On a hunch, I monitored the PCM data stream and noticed the processor would momentarily drop communication right before a stall. We swapped in a pre-programmed PCM just like this one, and the problem vanished. The old module’s internal circuits were failing under specific electrical loads, a classic sign of age-related failure these units are known for.
Common Signs of a Failing GM PCM
If your vehicle is experiencing any of the following, a faulty PCM could be the root cause. This module is the definitive fix for these common issues:
- ✔ Check Engine Light is illuminated with codes like P0601, P0602, or P0606 (Internal Controller Failure).
- ✔ The engine cranks but refuses to start.
- ✔ Unexplained stalling or rough idling, especially when coming to a stop.
- ✔ Poor fuel economy and a noticeable loss of power.
- ✔ Harsh or erratic automatic transmission shifting.
- ✔ Communication errors with your scan tool.
A Straightforward Guide to Installation
Installing your new 1999-2000 Silverado 1500 PCM is a job most DIYers can handle in their own driveway. Since we program it to your VIN, you can skip the expensive trip to the dealership.
- Safety First: Disconnect the negative terminal from your vehicle’s battery to prevent any electrical shorts.
- Locate the Old PCM: On most Silverado/Sierra models, the PCM is located in the engine bay, on the driver’s side, often under the battery or near the fender. On Express/Savana vans, it’s typically in the LH rear of the engine compartment.
- Disconnect the Harnesses: Carefully unclip and remove the electrical wiring harnesses connected to the module. These connectors have locking tabs that need to be released.
- Remove the Module: Unbolt the old PCM from its mounting bracket and remove it from the vehicle.
- Install the New PCM: Mount your new, pre-programmed module in the same location, reconnect the wiring harnesses securely, and re-fasten any bolts.
- Reconnect Battery: Re-attach the negative battery terminal.
- Perform Security Relearn: You will likely need to perform a simple security relearn procedure. This typically involves turning the key to the ‘ON’ position for 10-15 minutes, then off, and repeating two more times. This allows your vehicle’s anti-theft system to recognize the new PCM.
Verified Vehicle Compatibility List
This module, part number 16265035, is a direct replacement for a wide range of GM vehicles. It is also a compatible replacement for part numbers 16263494, 8162634940, 218-11787, and 21811787. Please verify your vehicle is on this list:
- Blazer S10 (98-00)
- C1500/C2500/C3500 Pickup (99-00)
- S10 Pickup (98-00)
- Silverado 1500 (99-00, 4.3L V6)
- Suburban 1500/2500 (99)
- Tahoe (99-00, Classic Style)
GMC Trucks & SUVs:
- Envoy (98-00)
- Jimmy S15 (98-00)
- C1500/C2500/C3500 Pickup (99-00)
- Sierra 1500 (99-00, 4.3L V6)
- Sonoma (98-00)
- Yukon / Yukon Denali (99-00)
- Astro (99-01)
- Express 1500/2500/3500 (99-02)
- Safari (99-01)
- Savana 1500/2500/3500 (99-02)
Other GM Models:
- Cadillac Escalade (99-00)
- Oldsmobile Bravada (98-00)
- Isuzu Hombre (98-00, 4.3L)
Frequently Asked Questions
How does the VIN programming work?
After you place your order, you simply provide us with your 17-digit Vehicle Identification Number (VIN). Our technicians use this to flash the module with the exact, factory-correct software and calibrations for your specific vehicle, ensuring a perfect match.
Is this a plug-and-play module?
Yes, for the most part. Because it arrives programmed to your VIN, it eliminates the need for dealer-level programming tools. You will, however, need to perform a simple security relearn procedure (detailed in our installation guide) which syncs the new PCM to your vehicle’s anti-theft system.
Do I need to perform a security relearn procedure?
Yes, this is a necessary step for most GM vehicles of this era. It’s a simple process that typically takes about 30 minutes and involves cycling the ignition key. This ensures your vehicle will start and run correctly with the new module.
What part numbers does this module replace?
This PCM is a direct, compatible replacement for several part numbers, including 16263494, 16265035, 8162634940, 218-11787, and 21811787. If your original module has any of these numbers, this part will work for you.
Will this fix my check engine light?
If the check engine light is on due to an internal failure of the PCM (common codes include P0601, P0606), then yes, this replacement module will solve the problem and allow the light to be cleared. It’s crucial to ensure the PCM is truly the faulty component.
Is there a core charge for my old module?
No, there is no core charge or need to return your old, faulty part. You can recycle it locally or simply dispose of it.