Restore Your Truck’s Performance and Reliability
As a technician with over two decades of experience under the hood, I’ve seen firsthand how a failing Powertrain Control Module (PCM) can bring a solid GM truck to its knees. If your 1998-1999 GMC 1500 is experiencing baffling issues like stalling, erratic shifting, or a persistent Check Engine Light, the problem often traces back to this central computer. This isn’t just a part; it’s the brain of your vehicle’s engine and transmission, and when it falters, nothing works right. That’s why we offer a dependable and straightforward solution.
This is a thoroughly tested, used OEM Powertrain Control Module. We take the guesswork and high cost out of the equation. Before this module ships, our experts will program it with the latest official GM software updates, specifically matched to your truck’s Vehicle Identification Number (VIN). This means it arrives at your door ready for installation, saving you a costly trip to the dealership and the hassle of finding someone with the right equipment for programming. Getting your workhorse back on the road shouldn’t be complicated, and with this module, it won’t be.
Is Your Truck Showing These Signs of a Bad PCM?
- ✔ Persistent Check Engine Light, often with codes like P0601 (Internal Control Module Memory Check Sum Error) or P0606 (PCM Processor Fault).
- ✔ Unexplained stalling or the engine shutting off while driving.
- ✔ Rough or inconsistent idling.
- ✔ The vehicle won’t start, even with a good battery and starter.
- ✔ Noticeable decrease in fuel economy.
- ✔ Harsh or erratic automatic transmission shifting.
- ✔ Failure to pass an emissions inspection.
Case Study: The Ghost in the Machine
A few years back, a 1999 Sierra 1500 was towed into my shop. The owner was at his wit’s end. He’d replaced the fuel pump, plugs, and wires, but the truck would still randomly stall at red lights. No specific codes were being thrown consistently, just a few random misfires. After checking all the vitals, I suspected the PCM. On these GMT400 and early GMT800 platforms, internal solder joints on the PCM’s circuit board can crack from years of heat cycles and vibration, causing intermittent connections. We swapped in a pre-programmed module like this one, and the truck ran perfectly. It’s a classic failure I’ve diagnosed hundreds of times, and a reliable programmed module is the definitive fix.
Your Straightforward 5-Step Installation Guide
- ✔ Safety First: Always disconnect the negative terminal from your vehicle’s battery and wait at least 10 minutes to ensure the system is fully powered down.
- ✔ Locate the Module: On most 1998-1999 GMC 1500 pickups, you’ll find the PCM mounted in the engine compartment on the driver’s side, near the firewall or inner fender.
- ✔ Disconnect the Old Unit: Carefully unplug the electrical harness connectors. They have locking tabs that need to be released. Avoid pulling on the wires themselves. Once disconnected, unbolt the module from its mounting bracket.
- ✔ Install the New Module: Bolt your new, pre-programmed PCM into the mounting bracket. Firmly reconnect the electrical harnesses, making sure you hear a ‘click’ to confirm they are securely locked in place.
- ✔ Reconnect and Finalize: Reconnect the negative battery terminal. In some cases, a security relearn procedure (often called a Passlock relearn) may be necessary. This procedure is simple and typically involves turning the key to the ‘ON’ position for 10-15 minutes. Consult your vehicle’s service information for exact steps.
Verified Vehicle Compatibility
This module is a direct replacement for multiple part numbers and fits a wide range of GM trucks, vans, and SUVs. Please verify that your original module has one of the following part numbers or the service ID 9355699. If you’re unsure, feel free to contact us with your VIN.
Interchangeable Part Numbers: 09355699, 16266645, 16250279, 16258815, 09366810, 9366810
This part is confirmed to fit models including:
- ✔ Chevrolet & GMC 1500/2500/3500 Pickups (1998-1999)
- ✔ Chevrolet Tahoe & GMC Yukon (1998-1999)
- ✔ Chevrolet & GMC Suburban (1998-1999)
- ✔ Chevrolet Express & GMC Savana Vans (1998-1999)
- ✔ Cadillac Escalade (1999)
- ✔ Chevrolet Astro & GMC Safari Vans (1998)
- ✔ Oldsmobile Bravada, Chevrolet S10 Blazer, GMC S15 Jimmy/Sonoma (1998)
- ✔ And more models sharing the 9355699 ID.
Do I need to do any programming to this PCM?
Do I need to do any programming to this PCM?
No. The main benefit of our service is that we program the module to your vehicle’s specific VIN before we ship it. It arrives ready to be installed, with no additional programming required.
What is a VIN and why do you need it?
The VIN (Vehicle Identification Number) is your car’s unique 17-digit serial number. It contains critical information about your vehicle’s engine, transmission, and factory options. We use it to load the exact, correct GM software for your specific build, ensuring perfect compatibility.
Is this a new part?
This is a high-quality, tested, used OEM module sourced from a salvaged vehicle. This provides an affordable and reliable alternative to expensive, and often unavailable, new dealership parts.
What is the difference between a PCM and an ECM?
The terms are often used interchangeably. ECM stands for Engine Control Module, while PCM stands for Powertrain Control Module. A PCM controls both the engine and the transmission, which is the case for this GM module. For all practical purposes in this application, the terms refer to the same part.
What if my part number is slightly different?
This module interchanges with several part numbers, as listed above. The most important identifier is often the service ID (e.g., 9355699). If your part number is on our list, it will work. If you’re unsure, just send us your VIN, and we will verify compatibility for you.