Restore Your Truck’s Brain and Get Back on the Road
Is your 1998-1999 GMC 1500 Pickup acting up? If you’re dealing with frustrating issues like a no-start condition, erratic engine behavior, poor fuel mileage, or a persistent Check Engine Light, the problem might be the very heart of your vehicle’s electronics: the Powertrain Control Module (PCM). As a technician with over 20 years of experience, I’ve seen firsthand how a failing PCM can cause a host of problems that seem impossible to pin down. This isn’t just a part; it’s the central command for your engine and transmission, and when it fails, your reliable truck can become a driveway ornament.
We offer a dependable and straightforward solution. This is a genuine, road-tested OEM PCM, carefully recovered from a salvaged vehicle and inspected for quality. The best part? We take the biggest headache out of the replacement process. We will flash this module with the latest official GM software updates, specifically programmed to your truck’s unique Vehicle Identification Number (VIN). This means you get a part that’s ready to install right out of the box, saving you from a costly trip to the dealership for programming.
Common Signs of a Failing PCM in Your GM Truck
If you’re experiencing any of the following, a faulty PCM could be the culprit. I’ve diagnosed hundreds of these, and these are the classic indicators:
- ✔ Check Engine Light is on with communication error codes like P0601, P0605, or P0606.
- ✔ Your engine cranks but refuses to start.
- ✔ The engine stalls, hesitates, or runs rough for no apparent reason.
- ✔ A noticeable drop in fuel economy.
- ✔ Harsh or incorrect automatic transmission shifting.
- ✔ Seemingly random electrical issues that other diagnostics can’t explain.
A Technician’s Notebook: The Intermittent Gremlin
A customer brought in his ’99 Sierra with a problem that was driving him crazy. It would run perfectly for days, then suddenly start stalling at red lights and shifting hard. He’d already replaced the spark plugs, wires, and even the fuel pump, with no luck. After connecting my scan tool, I noticed intermittent communication loss with the PCM. On a hunch, I gently tapped the module while the engine was running, and it immediately stumbled. The internal circuits were failing under heat and vibration. We installed a VIN-programmed PCM just like this one, performed the quick security relearn, and the truck has been running flawlessly ever since. It’s a textbook example of why a reliable 1998-1999 GMC 1500 PCM is critical.
A Straightforward Guide to Installation
Replacing the 1998-1999 GMC 1500 PCM is a job most DIYers can handle with basic tools. Our pre-programming service eliminates the most difficult step.
- Safety First: Disconnect the negative terminal from your truck’s battery to prevent any electrical shorts.
- Locate the PCM: On most of these trucks, the PCM is located in the engine compartment on the driver’s side, near the fender or firewall. It’s a silver metal box with several large electrical connectors.
- Disconnect Connectors: Carefully unclip and remove all electrical harness connectors from the old PCM. They often have locking tabs that need to be released.
- Remove the Old Module: Unbolt the PCM from its mounting bracket. Keep the hardware, as you’ll need it for the new module.
- Install the New PCM: Mount your new, pre-programmed PCM onto the bracket and secure it. Reconnect all the electrical connectors, ensuring they click securely into place.
- Reconnect Battery: Reattach the negative battery terminal.
- Perform Security Relearn: You will likely need to perform a simple security relearn procedure (often called Passlock or Passkey). This typically involves turning the key to the ‘ON’ position for 10-15 minutes. We include simple instructions for this vital step.
Verified Vehicle Compatibility List
This module, identified by part number 16250279 or service ID 9355699, is a direct fit for a wide range of GM vehicles. Please match your part number to ensure compatibility. This unit replaces part numbers: 09355699, 16266645, 16250279, 16258815, 09366810. It fits the following models:
- ASTRO 98 (LH front by battery)
- BLAZER S10/JIMMY S15 98 (RH front engine compartment)
- BRAVADA 98 (w/o build date opt ZN4)
- CADILLAC ESCALADE 99 (LH front engine compartment)
- CHEVROLET 1500 PICKUP 98-99 (Gasoline, LH engine compartment)
- CHEVROLET 2500 PICKUP 98-99 (Gasoline, LH front engine compartment)
- CHEVROLET 3500 PICKUP 98-99 (Gasoline, LH front engine compartment)
- ENVOY 98 (RH front engine compartment)
- EXPRESS 1500/2500/3500 VAN 98-99 (Gasoline)
- GMC 1500 PICKUP 98-99 (Gasoline, LH engine compartment)
- GMC 2500 PICKUP 98-99 (Gasoline, LH front engine compartment)
- GMC 3500 PICKUP 98-99 (Gasoline, LH front engine compartment)
- ISUZU HOMBRE 98 (4.3L)
- S10/S15/SONOMA 98 (4.3L)
- SAFARI (GMC) 98 (LH front by battery)
- SAVANA 1500/2500/3500 VAN 98-99 (Gasoline)
- SUBURBAN 1500/2500 98-99 (Gasoline, LH front engine compartment)
- TAHOE/YUKON 98-99 (Gasoline, LH engine compartment)
Choosing this tested and correctly programmed 1998-1999 GMC 1500 PCM is the most reliable and cost-effective way to solve complex electronic issues and restore the performance you expect from your truck.
Frequently Asked Questions
Why do you need my VIN?
Your VIN (Vehicle Identification Number) allows us to program the PCM with the exact software and calibrations your specific truck requires. This ensures proper engine performance, transmission shifting, and compatibility with your vehicle’s options.
Is this part difficult to install?
No. Since we program the module for you, the physical installation is simple. It involves basic hand tools to swap the module and performing a straightforward key-cycle security relearn procedure, which we provide instructions for.
Is this a new part?
This is a high-quality, used OEM part sourced from a salvaged vehicle. Each unit is inspected and tested before being programmed with the latest GM software for your VIN, offering OEM reliability at a fraction of the cost.
What if my part number is slightly different?
This module is a direct replacement for several part numbers, including 09355699, 16266645, 16258815, and more. As long as your vehicle is on the compatibility list and your original module matches one of the listed numbers, this part will work.
Will this fix my Check Engine Light?
If the Check Engine Light is caused by an internal PCM failure (codes like P0601, P0605, etc.), this replacement will resolve the issue. However, if the light is on due to a faulty sensor or other component, that separate issue will still need to be addressed.