Restore Your Truck’s Brain and Get Back on the Road
Is your reliable Chevy or GMC workhorse suddenly giving you headaches? Unexplained stalling, rough idling, erratic shifting, or a persistent Check Engine Light can often point to one culprit: a failing Powertrain Control Module (PCM). As a technician with over two decades of experience under the hood, I’ve seen how a faulty PCM can create some of the most frustrating and hard-to-diagnose issues. It’s the central computer of your vehicle, managing everything from fuel delivery and spark timing to transmission shift points. When it fails, your truck simply can’t operate as it should.
This isn’t just another part. This is a complete, ready-to-install solution. We take the guesswork and the expensive trip to the dealership out of the equation. Simply provide us with your vehicle’s VIN after purchase, and our experts will program this module with the latest factory software from GM, ensuring it’s a perfect match for your truck’s specific configuration. This is the most direct path to getting your 1999-2000 Chevrolet 3500 PCM replaced and your vehicle running smoothly again.
Case Study: The Ghost in the Machine
I remember a 2000 GMC Sierra 2500 that came into my shop. The owner was at his wit’s end. The truck would randomly refuse to start, but only when warm. No consistent codes, just pure frustration. We checked fuel pressure, spark, and sensors—all tested fine. After hours of diagnostics, we focused on the PCM. On these older GM trucks, years of heat cycles in the engine bay can cause microscopic cracks in the PCM’s circuit board. We swapped in a pre-programmed module, and the truck fired up instantly, every single time. It’s a classic failure mode for this platform, and a fresh, correctly programmed PCM is often the definitive fix.
Is Your GM Truck or Van Showing These Signs?
A failing PCM can manifest in many ways. If you’re experiencing any of the following, it might be time for a replacement. This is especially true if you see diagnostic trouble codes (DTCs) like P0601, P0604, or P0606, which point directly to an internal module fault.
- ✔ Check Engine Light is on or flashing
- ✔ Vehicle refuses to start or has intermittent starting issues
- ✔ Poor fuel economy
- ✔ Harsh or erratic automatic transmission shifting
- ✔ Engine stalling, stumbling, or misfiring
- ✔ Communication errors with your scan tool
- ✔ Failure to pass an emissions test
A Straightforward Guide to Installation
Replacing the 1999-2000 Chevrolet 3500 PCM is a job most DIYers with basic tools can handle. Since we program it beforehand, you won’t need any special computer equipment for the initial install. Just follow these steps carefully.
- Safety First: Disconnect the negative terminal from your vehicle’s battery and secure it away from the post to prevent accidental contact.
- Locate the PCM: On most trucks and SUVs listed, the PCM is located in the engine compartment, typically on the driver’s side fender well or near the battery. On Express and Savana vans, it’s often in the LH rear of the engine compartment.
- Disconnect the Connectors: Carefully unclip and remove the wiring harness connectors from the old PCM. These connectors have locking tabs that need to be released. Avoid pulling on the wires themselves.
- Remove the Old Module: Unbolt the PCM from its mounting bracket. Keep the hardware as you will reuse it for the new module.
- Install the New Module: Mount your new, pre-programmed PCM onto the bracket and securely fasten it.
- Reconnect Everything: Plug the wiring harness connectors firmly into the new PCM until they click into place. Reconnect the negative battery terminal.
- Perform Security/CASE Relearn: After installation, you may need to perform a security relearn procedure for the vehicle to start. Additionally, a Crankshaft Variation (CASE) relearn with a capable scan tool is highly recommended to prevent a P1336 trouble code and ensure optimal engine performance. Many local shops can perform this service for a small fee if you don’t have the tool.
Verified Vehicle Compatibility
This module, part number 16263494, is a direct replacement for a wide range of GM vehicles. We guarantee compatibility if your vehicle and original module ID are on this list. It is also a direct replacement for part numbers 16265035, 8162634940, 218-11787, and 21811787.
CHEVROLET 1500/2500 PICKUP 99-00 (Gasoline)
GMC 1500/2500/3500 PICKUP 99-00 (Gasoline)
SILVERADO/SIERRA 1500 PICKUP 99-00 (4.3L V6)
TAHOE/YUKON 99-00 (Classic/Denali)
SUBURBAN 1500/2500 99 (Gasoline)
ESCALADE 99-00
ASTRO/SAFARI VAN 99-01 (4.3L)
EXPRESS/SAVANA VAN 1500/2500/3500 99-02 (Gasoline)
S10/S15/SONOMA 98-00 (4.3L)
BLAZER/JIMMY 98-00 (4.3L)
BRAVADA 98-00 (4.3L)
ENVOY 98-00 (4.3L)
ISUZU HOMBRE 98-00 (4.3L)
(Note: Some 1998 models require build date option ZN4. Please verify your part number.)
Your Trusted Solution for a Reliable Repair
Don’t let a faulty computer keep your truck sidelined. This is more than just a part; it’s a professionally prepared solution that restores the performance and dependability you count on. By handling the complex programming for you, we make this a simple, effective repair. Order your pre-programmed 1999-2000 Chevrolet 3500 PCM today and get your truck back to work.
Why do you need my VIN?
Your Vehicle Identification Number (VIN) allows us to program the PCM with the exact software and calibrations your specific vehicle requires. This includes engine size, transmission type, and tire size, ensuring perfect compatibility and performance right out of the box.
Is this a simple plug-and-play installation?
Yes, for the most part. Because we program it to your VIN, you do not need a dealer-level scan tool for programming. However, on many GM vehicles of this era, you will need to perform a security relearn procedure (instructions can be found online) and a CASE (Crankshaft Variation) relearn with a capable scan tool for optimal performance.
Will this fix my transmission shifting problems?
In many cases, yes. The PCM controls the transmission solenoids and shift logic. If the module itself is faulty, it can cause hard shifting, slipping, or delayed engagement. Replacing a bad PCM often resolves these issues.
What if my original part number is not 16263494?
This module is also a direct replacement for several other part numbers, including 16265035 and 8162634940. Please check the compatibility list or contact us with your original part number to confirm fitment.
Do I need to send my old PCM back?
This listing does not require a core return. You can keep or responsibly recycle your old module.