Restore Peak Performance to Your GM Truck or Van
Is your trusty 1998-1999 GMC 2500 Pickup suffering from a persistent check engine light, erratic shifting, or a frustrating no-start condition? The Powertrain Control Module (PCM) is the brain of your vehicle’s operation, and when it fails, it can cause a host of confusing and performance-robbing issues. I’ve spent over two decades diagnosing these exact problems, and a faulty PCM is often the hidden culprit behind issues that mechanics might misdiagnose as bad sensors or fuel pumps.
This isn’t just a replacement part; it’s a complete, ready-to-install solution. We take a reliable, genuine GM computer sourced from a salvaged vehicle and professionally flash it with the latest official GM software updates. By programming it directly to your vehicle’s VIN before it ships, we eliminate the need for an expensive trip to the dealership for programming. You get a cost-effective part that’s ready to restore your engine’s proper function right out of the box.
A Technician’s Notebook
I remember a ’99 Chevy K2500 that came into the bay with a ghost of a problem. The owner said it would run fine for 20 minutes, then suddenly stall at a stoplight and refuse to restart for an hour. No consistent codes, just pure frustration. After checking fuel pressure and spark, which were fine when it was running, I suspected the PCM. On these GMT400 platforms, heat soak is a classic killer. We let the truck run until it stalled, then carefully cooled just the PCM with component cooler spray. It fired right back up. That confirmed the internal circuitry was failing when hot. A pre-programmed replacement like this one had him back on the road permanently the next day.
Is Your Truck Showing These Signs of PCM Failure?
- ✔ Check Engine Light is on with communication error codes (e.g., P0601, P0605, P0606).
- ✔ The engine cranks but refuses to start.
- ✔ Unexplained drops in fuel economy.
- ✔ The automatic transmission is shifting harshly, erratically, or not at all.
- ✔ Stalling, rough idling, or engine hesitation.
- ✔ Failure to pass an emissions/smog test.
A Straightforward Guide to Installation
- ✔ Safety First: Disconnect the negative terminal from your vehicle’s battery and wait 10-15 minutes for the system to fully discharge.
- ✔ Locate the PCM: On most 90s GM trucks and vans, the PCM is located in the engine compartment, typically on the driver’s side inner fender or near the battery.
- ✔ Disconnect Connectors: Carefully unclip and remove the electrical harness connectors from the old PCM. Inspect them for any corrosion or damaged pins.
- ✔ Remove the Old Unit: Unbolt the mounting brackets holding the old PCM in place and remove it from the vehicle.
- ✔ Install the New PCM: Mount your new, pre-programmed PCM in the same location and secure it with the original brackets.
- ✔ Reconnect Everything: Firmly plug the harness connectors into the new module. Reconnect the negative battery terminal.
- ✔ Final Steps: The vehicle may require a security relearn procedure, which typically involves turning the key to the ‘ON’ position for 10-15 minutes. This allows the new PCM to sync with your vehicle’s anti-theft system. Your truck should now start and run correctly.
Verified Vehicle Compatibility
This module, identified by service number 9355699, is a direct fit for a wide range of GM vehicles. Please match your existing part number to ensure compatibility. This part is interchangeable with the following numbers: 16266645, 09355699, 16250279, 16258815, 09366810, and 9366810.
Fits the following models (with ID 9355699):
- ASTRO 98
- BLAZER S10/JIMMY S15 98
- BRAVADA 98
- CADILLAC ESCALADE 99
- CHEVROLET 1500 PICKUP 98-99
- CHEVROLET 2500 PICKUP 98-99
- CHEVROLET 3500 PICKUP 98-99
- ENVOY 98
- EXPRESS 1500/2500/3500 VAN 98-99
- GMC 1500 PICKUP 98-99
- GMC 2500 PICKUP 98-99
- GMC 3500 PICKUP 98-99
- ISUZU HOMBRE 98
- S10/S15/SONOMA 98
- SAFARI (GMC) 98
- SAVANA 1500/2500/3500 VAN 98-99
- SUBURBAN 1500/2500 98-99
- TAHOE 98-99
- YUKON 98-99
Frequently Asked Questions
How do I provide my VIN number?
After completing your purchase, please send us a message with your 17-digit Vehicle Identification Number (VIN). We cannot program and ship the module without it.
Is this a new part?
No, this is a high-quality, tested computer that has been sourced from a properly salvaged vehicle. This allows us to provide a reliable and affordable solution.
Will I need to do anything after installation?
Because this 1998-1999 GMC 2500 PCM is pre-programmed to your VIN, it’s designed to be a plug-and-play installation. In some cases, a simple ‘key-on’ security relearn procedure may be needed, which takes about 10-15 minutes and requires no special tools.
Why is programming so important?
The VIN-specific programming ensures the PCM communicates correctly with your specific engine size, transmission type, and, most importantly, the vehicle’s anti-theft system (VATS). An unprogrammed module will result in a no-start condition.
Does my old part number have to match exactly?
Your module should have the identifier 9355699. However, this unit also replaces several other part numbers like 16266645, 16250279, and more. As long as your vehicle is on the compatibility list, this module will function correctly once programmed.