Restore Peak Performance to Your GM Truck or Van
Is your 1998-1999 Chevrolet 1500, Tahoe, Suburban, or other GM vehicle suffering from frustrating and hard-to-diagnose issues? A failing Powertrain Control Module (PCM) is often the hidden culprit behind problems like poor idling, erratic shifting, a persistent check engine light, or even a no-start condition. This module is the electronic brain of your vehicle, controlling everything from fuel mixture and ignition timing to transmission shift points. When it falters, the entire vehicle’s performance suffers. This replacement PCM, part number 16266645, is the definitive solution to get your truck back to running the way it was meant to.
The Smart Solution: VIN-Programmed for Your Vehicle
Don’t settle for a generic computer that requires an expensive trip to the dealership for programming. We take the hassle and extra cost out of the equation. Before this unit ships, we will flash it with the latest official GM software updates, specifically programmed to your vehicle’s unique Vehicle Identification Number (VIN). This ensures that all factory settings, anti-theft systems (PassLock/VATS), and specific options for your truck are correctly configured. The result is a seamless, plug-and-play installation process that restores factory functionality right out of the box.
From the Diagnostic Bay
I once had a 1999 GMC Yukon in the shop that was driving its owner crazy. It had a random misfire that wouldn’t set a specific code, and the transmission would occasionally shift hard into second gear. The owner had already replaced the spark plugs, wires, cap, rotor, and even the fuel pressure regulator. After hours of diagnostics, we traced the issue back to a failing PCM driver that was intermittently dropping the signal to an injector. Swapping in a VIN-programmed PCM like this one solved both the misfire and the harsh shifting instantly. It’s a reminder that the computer is the foundation of the entire system, and when it’s faulty, it can create symptoms that mimic many other failing parts.
Symptoms of a Failing 1998-1999 Chevrolet 1500 PCM
- ✔ Persistent Check Engine Light (CEL) with communication-related trouble codes (e.g., U-codes).
- ✔ Vehicle refuses to start or stalls intermittently for no apparent reason.
- ✔ Harsh, delayed, or erratic automatic transmission shifting.
- ✔ A noticeable drop in fuel economy and overall engine performance.
- ✔ Misfire codes that persist even after replacing ignition components.
- ✔ The cooling fans run constantly or not at all.
- ✔ Failure to pass state emissions inspections.
Guaranteed Compatibility and Reliability
This genuine used OEM computer is sourced from a salvaged vehicle and has been thoroughly inspected. While the hardware is used, the critical software is brand new, updated to the latest GM calibration for your specific vehicle. This provides the durability of original factory hardware with the performance and fixes of modern software. This module is a direct replacement for a wide range of part numbers, including 09355699, 16266645, 9355699, 16250279, 16258815, 09366810, and 9366810, ensuring broad compatibility across the GM truck and van lineup from 1998-1999. Please verify the part number on your original module to ensure a perfect match.
Frequently Asked Questions
What is VIN programming and why is it essential?
VIN programming loads your vehicle’s specific software and security information onto the PCM. This is critical for GM vehicles of this era, as it ensures the engine, transmission, anti-theft system (VATS/PassLock), and other vehicle options communicate and function correctly. Without it, the vehicle will not start or run properly.
Is this part difficult to install?
Installation is straightforward for someone with basic mechanical skills. It typically involves disconnecting the battery, unplugging the electrical connectors from the old PCM, unbolting it from its bracket in the engine bay, and then installing the new one in reverse order. Because it comes pre-programmed, no dealer visit is required. However, a ‘CASE Relearn’ (Crankshaft Angle Sensor Error) procedure may be needed with a compatible scan tool for optimal performance.
How do I provide my vehicle’s VIN?
After you complete your purchase, we will contact you via email to request your vehicle’s 17-digit VIN. We cannot ship the module until we have this information to perform the programming service.
Will this computer fix my transmission shifting problems?
If your transmission issues are caused by faulty signals or processing from the PCM, then yes, this part is very likely to solve the problem. The PCM controls transmission line pressure and shift solenoids, and a failing module is a common cause of harsh or erratic shifting in these trucks.
This is a used part. How can I be sure it will last?
This module is a genuine OEM part, built to GM’s high durability standards. Unlike many aftermarket alternatives, the original hardware is known for its robustness. Each unit is inspected and then loaded with fresh, updated software, which resolves many of the common failure points associated with the original programming.