If your 1999-2000 GMC Sierra or other compatible GM truck is suffering from puzzling electrical issues, you’ve come to the right place. As a technician with over two decades of experience under the hood, I’ve seen firsthand how a failing Powertrain Control Module (PCM) can cause massive headaches—from random stalling and no-start conditions to poor fuel mileage and a persistent Check Engine Light. This isn’t just a part; it’s the central computer of your vehicle, and when it falters, everything else does too.
This replacement PCM, part number 16263494, is the definitive solution. We take the guesswork and high dealership costs out of the equation. Before we ship it, we program the module with the latest official GM software updates, specifically matched to your truck’s Vehicle Identification Number (VIN). This means it arrives at your door ready for installation, with no need for an expensive trip to the dealer for programming. It’s the most direct path to restoring your truck’s performance and reliability.
A Technician’s Notebook: The Ghost in the Machine
I remember a 2000 Silverado 4.3L that came into my bay with an issue that had stumped two other shops. The owner complained of intermittent stalling at stoplights and a weird, delayed shift from first to second. There were no consistent trouble codes, just a history of random communication errors. After verifying the wiring harness and grounds were solid, my gut pointed to the PCM. The internal processors on these units can develop micro-fractures over years of heat cycles, causing unpredictable behavior. We installed a VIN-programmed PCM just like this one. The truck’s shifting became crisp, the stalling vanished, and the owner was thrilled to have his reliable workhorse back. This is often the fix for those ‘ghost’ problems that seem to have no other cause.
Is Your Truck Showing These Signs of a Failing PCM?
A faulty engine computer can manifest in numerous ways. If you’re experiencing any of the following, a new 1999-2000 Sierra 1500 PCM could be the answer:
- âś” Check Engine Light is on with codes like P0601 (Internal Control Module Memory Check Sum Error), P0605, or other communication faults.
- âś” The engine cranks but refuses to start.
- âś” Unexplained drops in fuel economy.
- âś” Harsh or erratic automatic transmission shifting.
- âś” The engine stalls unexpectedly, either while driving or at idle.
- âś” Apparent misfires even after replacing plugs and wires.
A Straightforward Guide to Your PCM Swap
Replacing the PCM on these GM trucks is a job most DIYers can handle with basic hand tools. For the 1999-2000 Sierra/Silverado, the module is typically located on the driver’s side, under the battery tray. Always consult a service manual for your specific model’s location.
- Safety First: Disconnect the negative terminal from your vehicle’s battery and secure it away from the post.
- Access the Module: On many trucks, you will need to remove the battery and the battery tray to gain clear access to the PCM.
- Disconnect Connectors: Carefully unplug the electrical 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 PCM: Unbolt the old module from its mounting bracket.
- Install the New PCM: Mount your new, pre-programmed PCM and securely reconnect the electrical harnesses. You should hear a ‘click’ as they lock into place.
- Reassemble: Reinstall the battery tray and battery, then reconnect the negative battery terminal.
- Perform Security Relearn: Your vehicle will likely require a simple security relearn procedure to recognize the new PCM. This usually involves turning the key to the ‘ON’ position for 10-15 minutes. Check your owner’s manual for the exact steps.
Verified Vehicle Compatibility
This module is a direct replacement for part numbers 16263494, 16265035, 8162634940, 218-11787, and 21811787. It fits a wide range of GM vehicles. Please verify your part number or contact us with your VIN to ensure a perfect match. Key compatible models include:
CHEVROLET 2500 PICKUP 00 Electronic Control Module; gasoline (LH front engine compartment)
EXPRESS 1500 VAN 00 Electronic Control Module; (LH rear engine compartment)
EXPRESS 2500 VAN 00 Electronic Control Module; (LH rear engine compartment), gasoline
EXPRESS 3500 VAN 00 Electronic Control Module; (LH rear engine compartment), gasoline
SAVANA 1500 VAN 01-02 Electronic Control Module; (LH rear engine compartment), ID 16263494
ASTRO 00-01 Electronic Control Module; (LH front by battery), ID 16263494
GMC 3500 PICKUP 00 Electronic Control Module; gasoline (LH front engine compartment)
EXPRESS 2500 VAN 01-02 Electronic Control Module; (LH rear engine compartment), gasoline, ID 16263494
S10/S15/SONOMA 99-00 Electronic Control Module; (RH front engine compartment), 4.3L
SAVANA 1500 VAN 00 Electronic Control Module; (LH rear engine compartment)
ASTRO 99 Electronic Control Module; (LH front by battery), (4.3L), ID 16263494
ISUZU HOMBRE 99-00 Electronic Control Module; (RH front engine compartment), 4.3L (6 cylinder)
SAFARI (GMC) 99-01 Electronic Control Module; (LH front by battery), ID 16263494
SAVANA 3500 VAN 01-02 Electronic Control Module; (LH rear engine compartment), gasoline, ID 16263494
EXPRESS 1500 VAN 99 Electronic Control Module; (LH rear engine compartment), ID 16263494
GMC 1500 PICKUP 99 Electronic Control Module; 5.0L, (LH engine compartment), ID 16263494
BLAZER S10/JIMMY S15 98 Electronic Control Module; (RH front engine compartment), w/build date opt ZN4
GMC 1500 PICKUP 99 Electronic Control Module; 5.7L, (LH engine compartment), ID 16263494
SAVANA 3500 VAN 99 Electronic Control Module; (LH rear engine compartment), gasoline, ID 16263494
SAVANA 3500 VAN 00 Electronic Control Module; (LH rear engine compartment), gasoline
TAHOE 00 Electronic Control Module; Classic style (LH front engine compartment)
YUKON 99 Electronic Control Module; (LH engine compartment), ID 16263494
ESCALADE 99 Electronic Control Module; (LH front engine compartment), ID 16263494
ESCALADE 00 Electronic Control Module; (LH front under battery)
EXPRESS 2500 VAN 99 Electronic Control Module; (LH rear engine compartment), gasoline, ID 16263494
S10/S15/SONOMA 98 Electronic Control Module; 6-262 (4.3L), w/build date opt ZN4
YUKON 00 Electronic Control Module; (LH front under battery), Denali
BRAVADA 98 Electronic Control Module; (6-262, 4.3L), w/build date opt ZN4
CHEVROLET 3500 PICKUP 00 Electronic Control Module; gasoline (LH front engine compartment)
ENVOY 99-00 Electronic Control Module; (RH front engine compartment)
EXPRESS 1500 VAN 01-02 Electronic Control Module; (LH rear engine compartment), ID 16263494
EXPRESS 3500 VAN 99 Electronic Control Module; (LH rear engine compartment), gasoline, ID 16263494
GMC 3500 PICKUP 99 Electronic Control Module; gasoline (LH front engine compartment), ID 16263494
ISUZU HOMBRE 98 Electronic Control Module; 4.3L (6 cylinder), w/extended build date opt ZN4
SIERRA 1500 PICKUP 99-00 Electronic Control Module; (LH front under battery), 6 cylinder
SAVANA 2500 VAN 00 Electronic Control Module; (LH rear engine compartment), gasoline
SUBURBAN 1500 99 Electronic Control Module; gasoline (LH front engine compartment), ID 16263494
CHEVROLET 1500 PICKUP 99 Electronic Control Module; 5.7L, (LH engine compartment), ID 16263494
EXPRESS 3500 VAN 01-02 Electronic Control Module; (LH rear engine compartment), gasoline, ID 16263494
GMC 2500 PICKUP 00 Electronic Control Module; gasoline (LH front engine compartment)
SILVERADO 1500 PICKUP 99-00 Electronic Control Module; (LH front under battery), 6 cylinder
SUBURBAN 2500 99 Electronic Control Module; gasoline (LH front engine compartment), ID 16263494
BLAZER S10/JIMMY S15 99-00 Electronic Control Module; (RH front engine compartment)
CHEVROLET 3500 PICKUP 99 Electronic Control Module; gasoline (LH front engine compartment), ID 16263494
SAVANA 1500 VAN 99 Electronic Control Module; (LH rear engine compartment), ID 16263494
TAHOE 99 Electronic Control Module; gasoline (LH front engine compartment), ID 16263494
BRAVADA 99-00 Electronic Control Module; (RH front engine compartment)
CHEVROLET 1500 PICKUP 99 Electronic Control Module; 5.0L, (LH engine compartment), ID 16263494
SAVANA 2500 VAN 99 Electronic Control Module; (LH rear engine compartment), gasoline, ID 16263494
SAVANA 2500 VAN 01-02 Electronic Control Module; (LH rear engine compartment), gasoline, ID 16263494
ENVOY 98 Electronic Control Module; (RH front engine compartment), w/build date opt ZN4
GMC 2500 PICKUP 99 Electronic Control Module; gasoline (LH front engine compartment), ID 16263494
Do I need to send my old PCM back?
No core charge is required for this module. You can keep your old part, which saves you the time and expense of return shipping.
How do I provide my VIN for programming?
After you complete your purchase, simply send us a message with your 17-digit VIN. We cannot ship your order until we receive this information, as the programming is essential for the module to function in your vehicle.
Is this a simple plug-and-play installation?
Yes, because we program it to your VIN, it is designed to be plug-and-play. However, as with most GM vehicles of this era, you will need to perform a simple security relearn procedure after installation. This takes about 10-15 minutes and requires only your ignition key.
Will this fix my specific problem?
This PCM is a direct fix for module-related failures, including internal processor faults (P0601) and other common symptoms. While it solves a wide range of issues, we always recommend a proper diagnosis to confirm the PCM is the point of failure before ordering. A new 1999-2000 Sierra 1500 PCM is often the final piece of the puzzle for many complex electronic issues.