Is Your 1999-2000 Sierra Running Rough? The PCM Might Be the Culprit.
The Powertrain Control Module, or PCM, is the central computer of your 1999-2000 GMC Sierra 1500. It’s the brain behind the entire operation, managing everything from fuel injection and ignition timing to transmission shift points and emissions controls. When this critical component begins to fail, it can cause a wide range of confusing and frustrating symptoms that can be difficult to diagnose. You might experience poor fuel economy, a persistent check engine light, or even a truck that refuses to start. This isn’t just an inconvenience; it’s a problem that affects your truck’s reliability, performance, and safety.
From the Diagnostic Bay
We had a 2000 Sierra 1500 with the 5.3L V8 come into the shop with a complaint of intermittent stalling and harsh shifting. The owner had already replaced the throttle position sensor and the mass airflow sensor, but the problem persisted. After hooking up our diagnostic scanner, we noticed erratic data coming from multiple sensors, but none were consistently failing. This is a classic sign of a failing PCM. The internal logic of the computer was corrupted, causing it to misinterpret perfectly good sensor inputs. We installed a VIN-programmed PCM, performed the security relearn procedure, and the truck ran like new. It saved the owner from throwing more money at parts he didn’t need.
Diagnosing a Faulty 1999-2000 Sierra 1500 PCM
A failing powertrain module can manifest in many ways, often mimicking other sensor or component failures. If your truck is exhibiting several of the following symptoms, there’s a strong possibility that your PCM is the root cause. This replacement module is the definitive solution to restore your truck’s factory performance and reliability.
Common Symptoms of PCM Failure:
- ✔ Check Engine Light: The check engine light is on, and you may have codes related to multiple, unrelated sensors, or internal processor failure codes (e.g., P0601, P0606).
- ✔ Engine Performance Issues: You may notice rough idling, stalling, hesitation during acceleration, misfires, or a significant drop in fuel economy.
- ✔ Transmission Problems: The PCM also controls the transmission. Failure can lead to harsh or erratic shifting, getting stuck in one gear (limp mode), or failure to shift at all.
- ✔ No-Start Condition: In severe cases, the PCM can fail completely, preventing the engine from starting. The engine may crank but will not fire up because the PCM isn’t commanding fuel or spark.
- ✔ Communication Errors: Your diagnostic scan tool may be unable to communicate with the PCM, which is a direct sign of a major internal fault.
The Simple, Reliable Solution: A VIN-Programmed Module
Don’t let a faulty computer keep your truck off the road. This Powertrain Control Module is a direct-fit replacement for your 1999-2000 Sierra 1500. The key to a successful repair is proper programming. We take the guesswork out of the equation by programming this module specifically for your truck using the VIN you provide. This ensures that all factory settings, including engine and transmission calibrations, anti-theft system data, and emissions parameters, are correct for your exact vehicle configuration. It arrives at your door ready for installation, loaded with the latest GM software updates to ensure optimal performance and longevity.
This module is a direct replacement for part numbers 19109040, 09354896, and 9354896 and fits a wide range of GM trucks and cars from that era. Please verify the fitment list below to ensure compatibility with your vehicle.
Frequently Asked Questions
Do I need to get this PCM programmed?
No. We handle the programming for you before we ship the part. Simply provide us with your vehicle’s 17-digit VIN during or after checkout, and we will flash the module with the correct factory software for your specific truck.
What is a VIN and why do you need it?
The VIN (Vehicle Identification Number) is a unique code for your truck. It contains information about the engine, transmission, emissions systems, and other options. Providing the VIN allows us to load the exact software your truck was built with, ensuring perfect compatibility.
Is any additional setup required after I install it?
In most cases, you will need to perform a security relearn procedure after installation. This syncs the new PCM with your truck’s anti-theft system and keys. This procedure is simple, requires no special tools, and instructions are readily available online or can be provided. A CASE (Crankshaft Angle Sensor Error) relearn may also be needed with a capable scan tool for optimal performance.
Will this fix my check engine light?
If the check engine light was caused by an internal failure of the original PCM, then yes, this replacement will resolve the issue. However, if there are other failing sensors or mechanical problems with your vehicle, the light may return. It is always best to have your vehicle properly diagnosed.
Where is the PCM located on my 1999-2000 Sierra?
On the 1999-2000 Sierra and Silverado pickups, the PCM is located in the engine bay on the driver’s side, underneath the battery tray.