Is Your Truck Running Rough? It Could Be The PCM.
If your 1999-2000 GMC Sierra 1500 is suffering from perplexing issues like a persistent check engine light, erratic shifting, poor fuel economy, or even a no-start condition, the problem may lie with its central computer: the Powertrain Control Module (PCM). As the brain of your vehicle, the PCM is responsible for managing everything from the fuel injectors and ignition timing to the transmission shift points. When it fails, it can cause a cascade of problems that are often difficult to diagnose.
This replacement Powertrain Control Module, part number 16263494, is the definitive solution to restore your truck’s performance and reliability. Forget about costly trips to the dealership for programming. We handle the critical software flashing process for you. Simply provide your vehicle’s VIN during checkout, and our technicians will program the module with the latest GM-certified software specific to your truck. This ensures a seamless, plug-and-play installation process, getting you back on the road faster.
From the Diagnostic Bay
We had a 2000 Chevy Silverado (which uses the same platform as the Sierra) come into the shop with a complaint of intermittent stalling at stoplights. The customer had already replaced the fuel pump and idle air control valve with no success. After hooking up our diagnostic scanner, we noticed that the PCM was intermittently losing communication with various sensors right before the stall. Instead of throwing parts at it, we swapped in a known-good, programmed PCM. The truck ran perfectly for a full day of testing. The original PCM’s internal drivers were failing under heat load, a classic symptom of module failure in these vehicles. This highlights why correctly identifying a faulty PCM is crucial.
Common Symptoms of a Failing PCM
- ✔ Persistent Check Engine Light (CEL) with various trouble codes
- ✔ Rough or inconsistent engine idling
- ✔ Harsh or delayed transmission shifting
- ✔ A noticeable decrease in fuel efficiency
- ✔ Engine stalling or hesitation during acceleration
- ✔ Complete no-start condition where the engine cranks but won’t fire
- ✔ Communication errors with diagnostic scan tools
Your Solution: A Properly Programmed 1999-2000 Sierra 1500 PCM
This module is a direct-fit replacement for your original unit, designed to meet or exceed OEM specifications. By programming it to your VIN, we ensure all factory settings, including those for your specific engine, transmission, and emissions equipment, are correctly loaded. This eliminates compatibility issues and ensures your truck runs exactly as it was designed to from the factory. The installation is straightforward, typically located in the engine bay under the battery tray on the driver’s side. Once installed, you may need to perform a simple security relearn procedure, which can often be done without special tools.
This unit is a direct replacement for multiple part numbers, including: 16263494, 16265035, 8162634940, 218-11787, and 21811787. It also fits a wide range of other GM trucks and vans from the same era, such as the Chevrolet Silverado, Tahoe, Suburban, Express, and GMC Yukon, Savana, and more. Please verify the part number to ensure proper fitment for your specific application.
Frequently Asked Questions
Do I need to get this PCM programmed by a dealer?
No. This is the key benefit of our service. We program the module with the latest GM software using the VIN you provide before we ship it. It arrives ready for installation.
What is the difference between an ECM, PCM, and ECU?
The terms are often used interchangeably. ECU (Engine Control Unit) is a general term. ECM (Engine Control Module) typically only controls engine functions. A PCM (Powertrain Control Module) is an integrated unit that manages both the engine and the transmission, which is what this module is.
Where is the PCM located on my 1999-2000 Sierra 1500?
On most 1999-2000 Sierra and Silverado models, the PCM is located in the engine compartment on the driver’s side, often under or near the battery tray.
Will this fix my check engine light?
If the check engine light is caused by a faulty internal circuit or software issue within your original PCM, then this replacement module will solve the problem. However, if the light is on due to a failing sensor or other mechanical issue, that component will still need to be addressed.
What is a security relearn and will I need to do one?
A security relearn, or anti-theft relearn, syncs the new PCM with your vehicle’s anti-theft system. Many GM vehicles of this era require this simple procedure after a PCM replacement to allow the engine to start. It typically involves a sequence of turning the key on and off and can be done without any special tools.