Is Your GM Truck or Van Running Rough?
If your late-90s Chevrolet or GMC is experiencing frustrating issues like stalling, no-start conditions, erratic shifting, or a persistent check engine light, the problem might be deeper than a simple sensor. The Powertrain Control Module (PCM), the central computer of your vehicle, is often the culprit. This vital component manages everything from fuel injection and ignition timing to transmission shift points. When it fails, it can cause a cascade of problems that are difficult to diagnose. This listing is for a dependable, used OEM GM engine computer, part number 09355699, that serves as a direct-fit replacement for a wide range of popular GM trucks and vans.
From the Diagnostic Bay
We had a 1999 Suburban in the shop that was driving the owner crazy. It had intermittent stalling and a no-start condition that would happen without warning. He had already replaced the fuel pump twice, thinking it was the issue. After hooking up our scanner, we noticed the fuel pump relay command was dropping out randomly. Instead of throwing another part at it, we traced the wiring back to the PCM. We found that the driver circuit inside the original PCM was failing intermittently, causing the fuel pump to cut out. We installed one of these VIN-programmed PCMs, performed the security relearn, and the truck has been running perfectly ever since. It’s a classic case where the root cause was electronic, not mechanical.
Symptoms of a Failing PCM
- ✔ Check Engine Light is on with communication error codes.
- ✔ Engine stalling or misfiring for no apparent reason.
- ✔ Vehicle won’t start, even with a good battery and starter.
- ✔ Harsh or erratic automatic transmission shifting.
- ✔ Noticeable decrease in fuel economy.
- ✔ Failure to pass emissions testing.
- ✔ Inconsistent or non-functional gauges on the instrument cluster.
The Right Solution for Your 1998-1999 Express 2500 PCM
Don’t let a faulty computer keep your reliable GM vehicle off the road. This isn’t just a used part pulled from a yard; it’s a complete solution. We take a genuine, tested OEM computer and program it specifically to your vehicle using your unique Vehicle Identification Number (VIN). This process ensures all factory settings and operational parameters are perfectly matched to your truck’s engine, transmission, and options. We also flash it with the latest available software updates from GM, which can resolve common drivability issues and improve overall performance and efficiency. This is a cost-effective way to restore your vehicle’s function without the high price of a new module from the dealership.
Simple Installation Process
Once you receive your programmed PCM, the physical installation is straightforward. However, please be aware that on most of these GM vehicles, a Security Relearn Procedure (often called Passlock or Passkey relearn) will be necessary after installation. This procedure syncs the new computer with your vehicle’s anti-theft system and is required for the engine to start and run. This can typically be done without special tools and involves a series of key cycles. We recommend searching for the specific procedure for your model year, but a common method is the “30-minute relearn procedure.”
This PCM is a direct replacement for part numbers: 09355699, 16266645, 9355699, 16250279, 16258815, 09366810, and 9366810. Please verify your original part number to ensure compatibility.
Frequently Asked Questions
Why do I need to provide my VIN?
Your Vehicle Identification Number (VIN) contains critical information about your truck’s engine, transmission, emissions systems, and other factory-installed options. We use your VIN to load the exact, correct GM software onto the PCM, ensuring it works seamlessly with your specific vehicle configuration.
Is this part difficult to install?
The physical replacement is usually simple, involving disconnecting the battery, unplugging a few electrical connectors, and unbolting the old module. The most important step is performing the Security Relearn Procedure after installation, which is required for the vehicle to start. This procedure can be done by most DIY mechanics.
Will this fix my check engine light?
If the check engine light and associated codes are caused by a faulty PCM, then this replacement will resolve the issue. However, it’s crucial to properly diagnose the problem first, as the light could be on for other reasons, such as a bad sensor or wiring issue.
What’s the difference between a PCM, ECM, and ECU?
The terms are often used interchangeably. ECM (Engine Control Module) typically just controls the engine. ECU (Electronic Control Unit) is a generic term. PCM (Powertrain Control Module) is the most accurate term for this part, as it controls both the engine and the automatic transmission functions in these GM vehicles.
This is a used part. Is it reliable?
Yes. These are genuine OEM (Original Equipment Manufacturer) parts, which are known for their durability. Each unit is sourced from a salvaged vehicle and tested for functionality before being programmed and shipped. It’s a reliable and economical alternative to a brand-new module.