Restore Peak Performance to Your GM Truck or Van
Is your 1998-1999 Chevrolet 3500, or another compatible GM vehicle, suffering from perplexing issues like a persistent check engine light, erratic shifting, stalling, or poor fuel economy? The Powertrain Control Module (PCM), often called the engine computer, is the brain of your vehicle’s operation. When it fails, it can cause a cascade of problems that are often difficult to diagnose. This genuine, used OEM Powertrain Control Module, part number 16266645, is the reliable and cost-effective solution to get your truck back on the road and running smoothly.
The Critical Role of Your 1998-1999 Chevrolet 3500 PCM
The PCM is a sophisticated computer that manages and monitors dozens of critical systems in real-time. It takes data from sensors all over your engine and transmission—like the oxygen sensors, throttle position sensor, and crankshaft position sensor—and uses that information to precisely control fuel injection, ignition timing, and transmission shift points. A healthy PCM ensures your engine operates at maximum efficiency, delivering the power you expect while minimizing emissions. A failing one can leave you stranded or with a vehicle that’s unreliable and frustrating to drive.
From the Diagnostic Bay
We had a ’99 GMC Yukon come into the shop with a complaint of intermittent stalling and a random misfire code that would jump from cylinder to cylinder. The customer had already replaced the spark plugs, wires, cap, and rotor. We checked fuel pressure, and it was perfect. After hours of chasing wires, we checked the main ground for the PCM on the engine block. It was slightly loose and corroded. After cleaning and tightening it, the issues vanished. Before you condemn your PCM, always check the simple things first: ensure your battery connections are clean and tight, and verify the main engine and PCM grounds are secure. A bad ground can mimic a faulty computer and save you hundreds of dollars.
Common Symptoms of a Failing PCM
- ✔ Persistent Check Engine Light (CEL) with various trouble codes.
- ✔ Engine stalling or randomly shutting off while driving.
- ✔ Harsh or erratic automatic transmission shifting.
- ✔ Noticeable decrease in fuel economy.
- ✔ Engine misfires or rough idling.
- ✔ No-start condition where the engine cranks but won’t fire up.
- ✔ Failure to communicate with a diagnostic scan tool.
Plug-and-Play Solution: VIN-Programmed for Your Vehicle
Replacing a PCM isn’t as simple as swapping the part. Each module contains vehicle-specific software that must match your truck’s Vehicle Identification Number (VIN), options, and emissions settings. This used PCM is taken from a salvaged vehicle and is a genuine OEM part, ensuring perfect physical fitment. More importantly, we eliminate the guesswork and the need for an expensive trip to the dealership. Simply provide us with your vehicle’s VIN during checkout, and our technicians will program the module with the latest GM-certified software updates specific to your truck. When it arrives, it’s ready for installation, making this a straightforward repair for a DIY mechanic or professional technician.
Compatible Part Numbers:
This module is a direct replacement for several part numbers. Please verify that your original module has one of the following numbers printed on its label: 09355699, 16266645, 9355699, 16250279, 16258815, 09366810, 9366810.
Extensive Vehicle Fitment:
This Electronic Control Module is compatible with a wide range of GM trucks, vans, and SUVs from 1998-1999, provided the part number on your original module matches. This includes models like the Chevrolet Silverado, Suburban, Tahoe, Express Van, GMC Sierra, Yukon, Savana Van, Cadillac Escalade, and more. Please consult the detailed fitment list and match your original part number to ensure compatibility.
Frequently Asked Questions
Why do you need my VIN?
Your Vehicle Identification Number (VIN) is essential for us to load the correct, vehicle-specific software onto the PCM. This programming ensures the module communicates properly with your engine, transmission, and other systems, and accounts for your vehicle’s specific options and emissions requirements.
Is any additional programming required after installation?
In most cases, no. Our programming makes this a plug-and-play installation. However, some vehicles may require a security relearn procedure (often called a CASE relearn or Passlock relearn) which can typically be done without a scan tool. Instructions for this procedure are widely available online for your specific model.
What is the difference between a PCM, ECM, and ECU?
The terms are often used interchangeably. ECU (Electronic Control Unit) is a generic term. ECM (Engine Control Module) typically only controls engine functions. A PCM (Powertrain Control Module) is an integrated unit that controls both the engine and the transmission, which is standard on the 1998-1999 Chevrolet 3500 PCM and related platforms.
Is this a new part?
No, this is a high-quality, tested, used OEM part sourced from a salvaged vehicle. This ensures you get a genuine factory component with proven reliability at a fraction of the cost of a new module from a dealership.
How do I locate the PCM on my truck?
On most of the compatible GM trucks and SUVs from this era (like the Chevrolet 3500), the PCM is located in the engine compartment, typically on the driver’s side inner fender or near the battery. On vans like the Express and Savana, it is often found in the left rear of the engine compartment.