Restore Peak Performance to Your GM Truck or Van
Is your truck suffering from a check engine light that won’t go away, erratic shifting, poor fuel economy, or a no-start condition? These are classic signs of a failing Powertrain Control Module (PCM), the central computer that manages your vehicle’s engine and transmission. This replacement PCM, part number 16265035, is the definitive solution to restore your vehicle’s factory performance, reliability, and efficiency. It serves as a direct-fit replacement for a wide range of late 90s and early 2000s GM vehicles, including the Chevrolet Silverado, GMC Sierra, Tahoe, Yukon, and Express/Savana vans.
From the Diagnostic Bay
We had a 1999 GMC Sierra 1500 come into the shop with a complaint that stumped a few other mechanics. The truck would randomly stall at idle, had a harsh 1-2 shift, and the check engine light would flicker on and off with no stored codes. We checked fuel pressure, ignition components, and even the wiring harness, but everything seemed fine. On a hunch, we connected a scope to the PCM’s sensor inputs and outputs. We discovered that the processor was intermittently dropping the signal to the fuel injectors. It wasn’t a complete failure, but a slow, frustrating decline. Swapping in a VIN-programmed PCM like this one solved every single issue instantly. The customer was thrilled to have his reliable truck back. These intermittent electronic faults can be the hardest to diagnose, and often, the PCM is the root cause.
Common Symptoms of a Failing PCM
The PCM is a complex component, and its failure can manifest in numerous ways. If you’re experiencing any of the following, it’s highly likely your engine computer is the culprit.
- ✔ Persistent Check Engine Light (CEL) illumination
- ✔ Engine stalling or misfiring
- ✔ Difficulty starting the engine or a complete no-start condition
- ✔ Poor or inconsistent engine performance
- ✔ Noticeable decrease in fuel economy
- ✔ Harsh or erratic automatic transmission shifting
- ✔ Failure to pass emissions testing
- ✔ Communication errors with diagnostic scan tools
Why Our VIN-Programmed 1999 GMC 1500 PCM is the Best Solution
Simply installing a used computer from another vehicle won’t work. Modern GM vehicles utilize a Vehicle Anti-Theft System (VATS) or Passlock system that is tied directly to the vehicle’s unique Vehicle Identification Number (VIN). Our process eliminates the guesswork and costly trips to the dealership. When you order, you provide us with your VIN. We then flash this module with the latest, most up-to-date software directly from GM, ensuring it is a perfect match for your truck’s specific configuration, including engine size, transmission type, and emissions equipment. This means no additional programming is required upon installation. It’s designed to be a true plug-and-play solution to get you back on the road quickly.
Installation and Post-Installation Procedures
Replacing the PCM is a straightforward process for a DIY mechanic. It is typically located in the engine bay on the driver’s side. Always disconnect the negative battery terminal before beginning work. Carefully unplug the wiring harnesses and unbolt the old module. Install the new module, reconnect the harnesses, and then reconnect the battery. While our programming handles the core functions, some vehicles may require a security relearn procedure or a Crankshaft Position Sensor (CASE) relearn to be performed with a capable scan tool for optimal performance and to clear any related trouble codes. This ensures the new computer is fully synchronized with all of your vehicle’s sensors.
Guaranteed Compatibility
This module is a direct replacement for several original equipment part numbers, ensuring broad compatibility. It is interchangeable with the following part numbers: 16263494, 16265035, 8162634940, 218-11787, and 21811787. Please verify your original part number or consult the detailed fitment list below to confirm this is the correct part for your vehicle.
Detailed Vehicle Fitment:
This Electronic Control Module fits a wide array of GM models. Please check your specific year, model, and engine options against this list:
- Astro / Safari (GMC): 1999-2001 (ID 16263494)
- Blazer S10 / Jimmy S15 / Envoy: 1998 (w/ build date opt ZN4), 1999-2000
- Bravada: 1998 (w/ build date opt ZN4), 1999-2000
- Chevrolet / GMC 1500, 2500, 3500 Pickups: 1999-2000 (Gasoline engines)
- Escalade: 1999-2000
- Express / Savana 1500, 2500, 3500 Vans: 1999-2002 (Gasoline engines, check ID)
- Isuzu Hombre: 1998 (w/ extended build date opt ZN4), 1999-2000 (4.3L)
- S10 / S15 / Sonoma: 1998 (w/ build date opt ZN4), 1999-2000 (4.3L)
- Sierra / Silverado 1500: 1999-2000 (4.3L 6-cylinder)
- Suburban 1500 / 2500: 1999 (Gasoline engines, ID 16263494)
- Tahoe / Yukon: 1999-2000 (Classic style / Denali)
Frequently Asked Questions
Why do I need to provide my VIN?
Your vehicle’s VIN is essential for us to program the PCM with the correct software from GM. This ensures compatibility with your engine, transmission, anti-theft system, and other specific options, making the installation process as simple as possible.
Is this part difficult to install?
For most DIY mechanics, the installation is straightforward. It involves disconnecting the battery, unplugging the electrical connectors, removing a few bolts, and swapping the module. It’s typically located in the engine compartment for easy access.
Will this fix my check engine light?
If the check engine light is caused by an internal failure of the PCM, then yes, this part will resolve the issue. However, the light can be triggered by many other components. It’s always best to have the codes read by a scanner to help pinpoint the problem before ordering.
What is a CASE relearn procedure?
A CASE (Crankshaft Angle Sensor Error) relearn is a procedure that synchronizes the new PCM with the crankshaft position sensor. On some GM vehicles, this may be required after installation to prevent a misfire code. It must be performed with a compatible bi-directional scan tool.
Is this a new or used part?
This is a high-quality, inspected replacement part that has been tested and prepared to meet or exceed original specifications. It is programmed with the latest software and is ready for installation in your vehicle.