Is Your Late 90s GM Truck or SUV Running Rough?
Your 1998-1999 GM vehicle is a workhorse, built to last. But after decades of reliable service, even the toughest components can wear out. The Powertrain Control Module (PCM), the electronic brain of your engine and transmission, is no exception. If you’re experiencing baffling issues like stalling, no-start conditions, erratic shifting, or a persistent check engine light, a failing PCM could be the culprit. Don’t let a faulty computer sideline your trusted vehicle. This pre-programmed PCM is the reliable, cost-effective solution to get you back on the road with confidence.
This isn’t just a used part pulled from a shelf. We take a quality, tested PCM and program it specifically to your vehicle’s unique VIN. This crucial step ensures that the computer is a perfect match for your truck’s engine, transmission, and factory options. We load the latest available GM software updates, which can resolve common drivability issues and improve overall performance and efficiency. This means you get a module that’s ready for installation, saving you a costly trip to the dealership for programming.
From the Diagnostic Bay
We once had a ’99 Suburban in the shop that was driving its owner crazy. It would die at stoplights intermittently, with no specific codes other than an occasional loss-of-communication error. The owner had already replaced the fuel pump and ignition control module. We hooked up our scope and noticed the 5-volt reference signal to the sensors would dip erratically right before a stall. This pointed to an internal failure in the original PCM. We installed one of our VIN-programmed modules, performed the security relearn, and the truck ran perfectly. The problem wasn’t a bad sensor or wire; it was the computer itself slowly failing. This is a classic symptom for this generation of 1998-1999 GM Truck PCM.
Symptoms of a Failing PCM
- ✔ Check Engine Light is on with codes related to internal module failure or sensor circuits (e.g., P0601, P0605).
- ✔ Engine stalls for no reason, either while driving or at idle.
- ✔ Vehicle refuses to start, but the battery and starter are good.
- ✔ Harsh or erratic automatic transmission shifting.
- ✔ Noticeable decrease in fuel economy.
- ✔ Communication errors when trying to read codes with a scan tool.
- ✔ One or more fuel injectors or ignition coils stop working intermittently.
The Critical VIN Programming Step
Ordering is simple. After you complete your purchase, just provide us with your 17-digit VIN. Our technicians will use this information to flash the module with the exact software your vehicle requires. This ensures seamless integration and proper function of all systems. This unit is a direct replacement for multiple service numbers, including 09355699, 16266645, 16250279, 16258815, and 9366810. By matching the software to your VIN, we guarantee compatibility across this wide range of applications.
Installation Note: Security Relearn Procedure
After installing your new PCM, you will need to perform a security relearn procedure (often called a VATS or Passlock relearn). This is a simple process that syncs the new computer with your vehicle’s anti-theft system. It typically involves turning the key to the ‘ON’ position for 10 minutes, then ‘OFF’ for 10 seconds, and repeating this sequence three times. This procedure does not require special tools and is a necessary final step for the vehicle to start and run with the replacement module.
Frequently Asked Questions
Do I absolutely have to provide my VIN?
Yes. Providing your Vehicle Identification Number (VIN) is mandatory. We cannot ship the module without it. The VIN is required to load the correct GM software and calibrations for your specific engine, transmission, and emissions equipment, ensuring a perfect match.
Is this part difficult to install?
Physically replacing the PCM is straightforward. It’s typically located in the engine bay and held in by a few bolts. The most important part of the installation is performing the security relearn procedure afterward, which is required for the engine to start. Basic hand tools are all that’s needed.
My original part number is 09355699. Will this work?
Yes, absolutely. This PCM, part number 9366810, is a direct replacement and supersedes several older part numbers, including 09355699. As long as your vehicle is on the compatibility list, this module will function correctly once programmed to your VIN.
Is this a new computer?
No, this is a high-quality, tested used computer sourced from a salvaged vehicle. Each unit is inspected and verified to be in good working condition before being programmed and shipped.
Will this fix my check engine light?
If the check engine light is caused by a faulty PCM, then yes, this will resolve the issue. However, it’s crucial to properly diagnose your vehicle first. This module will not fix problems related to other bad sensors, wiring, or mechanical components.