Is Your GM Truck or SUV Running Rough?
If you’re dealing with frustrating issues like stalling, poor fuel mileage, erratic shifting, or a persistent check engine light in your 1998 GMC Envoy or a similar GM vehicle, a failing Powertrain Control Module (PCM) is often the culprit. As the central computer of your vehicle, the PCM is responsible for managing everything from fuel injection and spark timing to transmission shift points. When it begins to fail, it can cause a wide range of perplexing and seemingly unrelated problems, making your vehicle unreliable and difficult to drive.
Don’t let a faulty computer keep you off the road. This is a direct replacement, genuine OEM used PCM, part number 16266645, that has been meticulously tested and is ready to restore your vehicle’s performance. The best part? We handle the complex programming for you. Simply provide your vehicle’s VIN during checkout, and our technicians will flash the module with the latest, most up-to-date software directly from GM. This ensures a seamless installation and optimal performance, saving you a costly trip to the dealership.
From the Diagnostic Bay
We once had a ’99 Suburban come into the shop with an intermittent no-start condition that was driving the owner mad. It would crank but wouldn’t fire, yet there were no consistent trouble codes. We checked the fuel pump, ignition system, and sensors—all tested fine. On a hunch, we connected a lab scope to the PCM’s injector driver circuits. Sure enough, we saw the signal drop out randomly during cranking. The PCM was failing internally under load. We installed one of these VIN-programmed modules, and the truck fired up on the first try and never had the problem again. It’s a classic case of the vehicle’s ‘brain’ being the ghost in the machine.
Symptoms of a Failing 1998 Envoy PCM
- ✔ Persistent Check Engine Light (CEL) that won’t clear, or communication error codes (U-codes).
- ✔ Unexplained engine stalling or cutting out while driving.
- ✔ Rough or inconsistent idling.
- ✔ Noticeable decrease in fuel economy.
- ✔ Harsh or erratic automatic transmission shifting.
- ✔ Engine cranks but refuses to start.
- ✔ Intermittent issues that seem to have no other logical cause.
The Perfect Solution: Pre-Programmed and Ready to Install
Replacing a PCM isn’t just about swapping hardware. The software is critical. This module is not just a part; it’s a complete solution. By programming it to your specific VIN, we ensure that it has the correct calibration for your vehicle’s engine, transmission, and options. This service eliminates the need for expensive dealer-only tools and procedures, making this a straightforward repair for a competent DIY mechanic or any professional repair shop.
This PCM is a compatible replacement for a wide range of part numbers, including 09355699, 16266645, 9355699, 16250279, 16258815, 09366810, and 9366810. It fits a huge variety of popular GM trucks and vans from the late 90s, such as the Chevrolet Silverado, GMC Sierra, Tahoe, Yukon, Suburban, Express, Savana, and more. Please verify the part number or consult our detailed fitment list to confirm compatibility with your exact model.
Installation Note
While this module is delivered programmed to your VIN, some GM vehicles of this era may require a simple security relearn procedure or a Crankshaft Variation (CASE) relearn after installation. This can typically be performed with a capable bi-directional scan tool or, in some cases, by following a specific key-on/key-off sequence. This final step syncs the new PCM with your vehicle’s anti-theft system and crankshaft position sensor for flawless operation.
Frequently Asked Questions
Do I need to program this PCM?
No, you don’t! We handle all the programming before we ship the part. Just provide us with your vehicle’s 17-digit VIN when you place your order, and we will flash the module with the latest GM software specific to your vehicle.
Is this a new part?
This is a high-quality, tested, and fully functional used OEM (Original Equipment Manufacturer) part sourced from a salvaged vehicle. This provides OEM reliability at a fraction of the cost of a new module from a dealership.
What information do you need from me?
All we need is your vehicle’s VIN (Vehicle Identification Number). This ensures we load the correct software and calibrations for your specific engine, transmission, and factory options.
My old computer has a different part number on it. Will this still work?
Yes, this module is a direct replacement for several part numbers, including 09355699, 16266645, 9355699, and others listed in the description. GM often supersedes part numbers, and this unit covers a wide range of original hardware.
Will I need to do anything else after installing it?
In some cases, you may need to perform a security relearn or a CASE (Crankshaft Position System Variation) relearn. This is a standard procedure for many GM vehicles when the PCM is replaced and can be done by most repair shops or with a high-end scan tool.