Is Your GM Truck or Van Running Rough?
If you’re dealing with frustrating issues like a persistent check engine light, stalling, poor fuel mileage, or erratic transmission shifting in your 1999-2000 Chevrolet Silverado 1500, the problem may lie with a failing Powertrain Control Module (PCM). As the central computer of your vehicle, the PCM is responsible for managing everything from fuel injection and ignition timing to transmission shift points. When it begins to fail, it can cause a wide range of confusing and difficult-to-diagnose symptoms.
From the Diagnostic Bay
We once had a ’99 Sierra in the shop that was a real head-scratcher. The owner had already replaced multiple sensors and the fuel pump, but the truck would still randomly stall and idle poorly. After connecting our diagnostic scanner, we saw intermittent data dropouts from the PCM, especially once the engine bay warmed up. The internal processor was failing. We installed one of these VIN-programmed modules, performed the security relearn, and the truck ran like new. It’s a classic example where chasing individual symptoms can be costly, while the root cause is the central computer itself.
Symptoms of a Failing Powertrain Control Module
- ✔ Persistent Check Engine Light (CEL) with various trouble codes.
- ✔ Engine stalling, stumbling, or refusing to start.
- ✔ Noticeable decrease in fuel economy.
- ✔ Harsh, delayed, or incorrect automatic transmission shifting.
- ✔ Rough or unstable engine idle.
- ✔ Failure to pass emissions testing.
- ✔ No communication with diagnostic scan tools.
The Direct-Fit Solution: A VIN-Programmed 1999-2000 Silverado PCM
This replacement Powertrain Control Module, part number 16265035, is the definitive solution to get your vehicle back on the road and running reliably. We take the guesswork out of the repair. Simply provide us with your vehicle’s VIN (Vehicle Identification Number) during checkout, and our technicians will flash the module with the latest, most up-to-date software directly from GM. This ensures perfect compatibility with your truck’s specific engine, transmission, and options.
By programming the module before it ships, we eliminate the need for an expensive trip to the dealership for coding. This module arrives ready for installation, making it a straightforward job for a DIY mechanic or your trusted local shop. It is a direct replacement for OEM part numbers 16263494, 16265035, 8162634940, 218-11787, and 21811787, and fits a wide range of GM trucks and vans from 1998-2002. Please verify the comprehensive fitment list to confirm compatibility with your exact model.
Frequently Asked Questions
What does the PCM actually do?
The Powertrain Control Module (PCM) is the main computer that controls your vehicle’s engine and transmission. It takes data from dozens of sensors to manage fuel delivery, spark timing, emissions systems, and transmission shifting to ensure optimal performance and efficiency.
Do I need to program this module?
No. This module comes pre-programmed to your vehicle’s specific VIN. You must provide your VIN at the time of purchase so we can load the correct GM factory software before shipping it to you. This makes installation much simpler.
Where is the PCM located on my 1999-2000 Silverado?
On most 1999-2000 Silverado and Sierra trucks with the 4.3L V6 engine, the PCM is located in the engine compartment on the driver’s side, often under the battery tray. On other compatible vehicles like Express/Savana vans, it may be in the rear of the engine compartment. Always disconnect the battery before attempting replacement.
Will I need to perform any other procedures after installation?
In many cases, you may need to perform a security relearn procedure (also known as a Passlock relearn) to allow the vehicle to start. This procedure can often be done without special tools and involves a sequence of key cycles. Additionally, a Crankshaft Variation Relearn (CASE relearn) may be needed to clear certain trouble codes, which typically requires a compatible bi-directional scan tool.
Is this a new or used part?
This is a high-quality, serviced original equipment part that has been tested and prepared for reliable, long-term service. It is programmed with the latest software and functions as a direct replacement for your original failed unit.