Restore Your Truck’s Reliability and Performance
Is your 1999-2000 GMC Sierra 1500 or other GM truck acting up? Unexplained stalling, rough idling, poor fuel mileage, and a persistent Check Engine Light are more than just annoyances—they’re signs that the engine’s central computer may be failing. As a technician with over two decades of experience, I’ve seen countless drivers chase expensive sensor replacements when the real problem was a faulty Powertrain Control Module (PCM). This module is the brain of your engine, and when it malfunctions, the entire vehicle suffers. Don’t let a failing PCM leave you stranded. This replacement unit is the dependable, straightforward solution to get your truck running like it should.
We make this repair process simple. This isn’t just a generic part off a shelf; it’s a dedicated solution for your vehicle. Before we ship it, we will program the module with the latest official GM software updates, specifically matched to your truck’s Vehicle Identification Number (VIN). This critical step ensures perfect communication between your engine and transmission, restoring factory performance and efficiency. By providing a fully programmed 1999-2000 Sierra 1500 PCM, we eliminate the need for an expensive trip to the dealership for programming. It arrives at your door ready for installation.
A Technician’s Notebook
I remember a 2000 Silverado 1500 that came into the shop with a laundry list of complaints: intermittent no-start, stalling at red lights, and a transmission that shifted erratically. The owner had already replaced the throttle position sensor and the mass air flow sensor with no improvement. His scanner showed a P0601 (Internal Control Module Memory Check Sum Error) code, which is a dead giveaway for a failing PCM. We explained that the PCM’s internal memory was corrupted, causing it to send bad commands to the rest of the vehicle. We installed a VIN-programmed module, and the difference was immediate. The truck started instantly, idled smoothly, and shifted perfectly. It’s a classic case where fixing the core problem—the computer—is the only real solution.
Is Your GM Truck Showing These Symptoms?
- âś” Check Engine Light is on with codes like P0601, P0605, or other communication errors.
- âś” The engine cranks but refuses to start.
- âś” Your vehicle experiences random stalling or hesitation while driving.
- âś” Noticeable decrease in fuel economy.
- âś” The transmission shifts harshly or at the wrong times.
- âś” Failure to pass an emissions test due to module-related faults.
A Straightforward Guide to Installation
- âś” Safety First: Always disconnect the negative terminal from your vehicle’s battery before starting any electrical work.
- âś” Locate the PCM: On most 1999-2000 Sierra/Silverado models, the PCM is located in the engine compartment, on the driver’s side, often under or near the battery tray.
- âś” Disconnect Connectors: Carefully unclip and remove the electrical harness connectors from the old module. These connectors have locking tabs that need to be released. Avoid pulling on the wires themselves.
- âś” Remove the Old Module: Unbolt the old PCM from its mounting bracket. It’s typically held in place by a few bolts.
- âś” Install the New Module: Mount your new, pre-programmed PCM onto the bracket and secure the bolts.
- âś” Reconnect Everything: Firmly plug the electrical connectors into the new module until they click into place. Reconnect the negative battery terminal.
- âś” Final Check: Turn the key to the ‘On’ position for 10 seconds before starting the engine. This allows the system to recognize the new module. Start your vehicle and enjoy restored performance.
Will This Fit My Truck or Van?
This module is a direct replacement for part numbers 16263494, 16265035, 8162634940, 218-11787, and 21811787. It is guaranteed to fit a wide range of GM vehicles. Please verify your vehicle is on the list below. This is the correct 1999-2000 Sierra 1500 PCM for 6-cylinder models and also fits many other applications:
- GMC/Chevrolet Pickups (1500/2500/3500): 1999-2000
- GMC Sierra/Chevy Silverado 1500 (6-cyl): 1999-2000
- GMC/Chevrolet Vans (Express/Savana 1500/2500/3500): 1999-2002
- Chevy Tahoe / GMC Yukon (incl. Denali): 1999-2000
- Cadillac Escalade: 1999-2000
- Chevy Astro / GMC Safari: 1999-2001
- Chevy S10 / GMC Sonoma / Isuzu Hombre (4.3L): 1998-2000
- Chevy Blazer / GMC Jimmy / Oldsmobile Bravada / GMC Envoy (4.3L): 1998-2000
Frequently Asked Questions
Frequently Asked Questions
Do I need to do anything after installing this PCM?
No. Because this module is pre-programmed to your VIN, it is ready for installation right out of the box. In some cases, a Crankshaft Variation Relearn procedure may be needed, which can be done with a capable scan tool or by a local shop.
How do I provide my VIN?
After you complete your purchase, you will receive instructions on how to send us your vehicle’s 17-digit VIN. We cannot ship your part until we receive this information.
Is this a new or used part?
This is a high-quality, inspected, and tested recycled OEM part. Each unit is verified to be fully functional before being programmed with the latest GM software for your specific vehicle.
Will this fix my transmission shifting problems?
In many cases, yes. The PCM controls both engine and transmission functions. If your shifting issues are caused by faulty electronic commands from a failing module, this part will correct them.
What is the difference between a PCM and an ECM?
The terms are often used interchangeably. PCM (Powertrain Control Module) is the more accurate term for these GM vehicles as it controls both the engine (Engine Control Module – ECM) and transmission functions in one unit.
What if my original part number is not 16265035?
This module is also a direct replacement for part numbers 16263494, 8162634940, 218-11787, and 21811787. As long as your vehicle is on the compatibility list, this module will work.