Is Your 1998-1999 GM Truck or Van Running Rough?
The Powertrain Control Module (PCM), often called the engine computer, is the electronic brain of your vehicle. It manages everything from fuel injection and ignition timing to transmission shifting and emissions control. When it starts to fail, it can cause a cascade of confusing and frustrating problems that can be difficult to diagnose. If your truck is stalling, getting poor gas mileage, or has an illuminated Check Engine Light, a faulty PCM could be the culprit.
This is a direct replacement Powertrain Control Module for a wide range of 1998-1999 General Motors vehicles. It is a genuine, used OEM part that has been carefully inspected and is ready for service. The most critical part of the replacement process is programming, and we handle that for you. Simply provide your vehicle’s 17-digit VIN during checkout, and our technicians will flash the module with the latest GM-certified software specific to your truck or van. This ensures proper communication with all other vehicle systems and restores original factory performance.
From the Diagnostic Bay
We had a 1999 Chevy Tahoe come into the shop that was driving the owner crazy. It would randomly stall at stoplights, and sometimes it wouldn’t start back up for 10-15 minutes. He had already replaced the fuel pump and the ignition control module, but the problem persisted. We hooked up our scanner and noticed intermittent communication loss with the PCM. After confirming all power and ground circuits to the computer were solid, we knew the internal logic of the PCM itself was failing. We installed one of these VIN-programmed modules, performed the quick security relearn, and the Tahoe ran like new. The owner was thrilled to finally have a reliable vehicle again.
Diagnosing a Faulty 1998-1999 GMC 1500 PCM
A failing engine computer can mimic the symptoms of many other failing parts, making it a tricky diagnosis. However, certain patterns often point directly to the PCM. Look out for multiple, unrelated trouble codes, or codes that indicate a communication failure (U-codes). If you’re experiencing any of the issues below and have ruled out more common causes like sensors or wiring, it’s time to consider the PCM.
Common Symptoms of a Failing PCM
- ✔ Check Engine Light is on with various, often inconsistent, diagnostic trouble codes.
- ✔ Engine stalling or shutting off randomly while driving or at idle.
- ✔ No-start or hard-start condition, even with a good battery and starter.
- ✔ Noticeable decrease in fuel economy.
- ✔ Harsh or erratic automatic transmission shifting.
- ✔ The engine runs rough, misfires, or hesitates during acceleration.
- ✔ Failure to pass an emissions test.
The Simple, Reliable Solution
Don’t let a faulty computer keep your truck off the road. This module is a cost-effective and reliable solution. By providing us with your VIN, you bypass the need for expensive dealership programming or specialized scan tools. The module arrives at your door ready to be installed. In most cases, a simple security relearn procedure (which can be done without tools) is all that’s needed to get your vehicle running again. This part is a direct replacement for service numbers 09355699, 16266645, 9355699, 16250279, 16258815, 09366810, and 9366810, and fits a massive range of GM trucks and vans from the era. Please verify the part number on your original module to ensure compatibility.
Frequently Asked Questions
Do I need to get this PCM programmed?
No. We handle the programming for you before we ship the part. You must provide us with your vehicle’s 17-digit VIN so we can load the correct software for your specific make, model, and options.
Is this a new part?
No, this is a high-quality, tested used OEM part sourced from a salvaged vehicle. Each unit is inspected to ensure it is fully functional and ready for programming and installation.
How do I provide my VIN?
You can add your VIN to the notes section during the checkout process. If you forget, we will contact you via email after your purchase to request the information. We cannot ship your part until we have programmed it.
Will I need to do anything after installing it?
In most cases, you will need to perform a security relearn procedure, also known as a CASE relearn. This syncs the new computer with your vehicle’s anti-theft system. This procedure is simple and typically involves turning the key on and off in a specific sequence. Instructions are readily available online for your specific model.
Will this fix my truck’s problem for sure?
This part will correct any issues directly caused by a failing PCM. If your vehicle exhibits symptoms like random stalling, communication error codes, or erratic engine behavior that have not been solved by replacing other components, this is very likely the solution. However, proper vehicle diagnosis is always recommended.