Restore Peak Performance to Your GM Truck or SUV
Is your 1998 GMC Envoy, Chevrolet truck, or GMC van running rough, stalling, or displaying a persistent Check Engine Light? These are common indicators of a failing Powertrain Control Module (PCM), the central computer responsible for managing your vehicle’s engine and transmission. A faulty PCM can lead to a cascade of issues, including poor fuel economy, erratic shifting, and even a no-start condition. Don’t let a bad computer keep your reliable GM vehicle off the road. This genuine, used OEM PCM, part number 09355699, is the definitive solution to restore its original performance and reliability.
The Brain of Your Vehicle: Understanding the PCM’s Role
The PCM is the electronic brain of your vehicle. It processes information from dozens of sensors throughout the engine and transmission to make real-time adjustments to fuel delivery, spark timing, transmission shift points, and emissions controls. When it functions correctly, your engine runs smoothly and efficiently. However, due to age, heat cycles, and electrical stress, these modules can fail, causing significant drivability problems. Replacing a faulty module is not just about fixing a symptom; it’s about restoring the core of your vehicle’s operational command system.
Expert Pro Tip
Before installing your replacement PCM, it’s crucial to disconnect the vehicle’s battery for at least 30 minutes. This step ensures that all other vehicle modules clear any stored fault codes or adaptive memory related to the old, failing PCM. This ‘hard reset’ allows the vehicle’s systems to properly recognize and communicate with the newly installed, correctly programmed computer from a clean slate, preventing potential communication errors after installation.
Why Our Programmed 1998 Envoy PCM is the Smart Choice
This isn’t just a used part pulled from a shelf. We offer a complete, plug-and-play solution. Each module is meticulously programmed to your vehicle’s specific Vehicle Identification Number (VIN) before it ships. This critical step ensures that the PCM has the correct software and calibrations for your Envoy’s engine, transmission, and specific options. This eliminates the need for an expensive trip to the dealership for programming, saving you time and hundreds of dollars. You are getting a cost-effective, tested OEM part that is ready for installation right out of the box.
Symptoms of a Failing PCM
- ✔ Check Engine Light: The most common sign, often with codes related to module communication or sensor circuits.
- ✔ Engine Stalling or Misfiring: The engine may stall intermittently, run rough, or misfire as the PCM fails to properly control fuel and spark.
- ✔ No-Start Condition: In severe cases, the PCM may fail to activate the fuel pump or ignition system, preventing the engine from starting at all.
- ✔ Poor Fuel Economy: Incorrect fuel mixture and timing calculations can cause a sudden and significant drop in MPG.
- ✔ Harsh or Erratic Shifting: The PCM also controls the transmission, and failure can lead to delayed, hard, or incorrect gear shifts.
- ✔ Failed Emissions Test: A malfunctioning PCM can prevent emissions systems from operating correctly, leading to a failed smog check.
Guaranteed Compatibility
This PCM, identified by part number 09355699, is a direct replacement for several other service numbers, including 16266645, 9355699, 16250279, 16258815, and 09366810. It is designed for a wide range of 1998 and 1999 GM trucks, vans, and SUVs. Please verify your part number and consult the detailed fitment list below to ensure this is the correct component for your vehicle. Providing your VIN for programming is the final step to guarantee a perfect match.
By choosing this pre-programmed 1998 Envoy PCM, you are making an intelligent repair. You’re getting an affordable, reliable OEM part that has been prepared specifically for your vehicle, ensuring a straightforward installation and a lasting solution to your engine management problems.
Frequently Asked Questions
How do I provide my VIN for programming?
After you complete your purchase, you will receive instructions on how to send us your vehicle’s 17-digit VIN. You can typically reply to your order confirmation email or send it through our website’s contact form. We cannot ship the module until we have this information.
Is this part difficult to install?
For someone with basic mechanical skills, the installation is straightforward. It typically involves disconnecting the battery, unplugging the electrical connectors from the old PCM, unbolting it from its bracket, and then installing the new one in the reverse order. Since our unit comes pre-programmed, no special tools are required for software setup.
What is a security or CASE relearn, and will I need one?
In some GM vehicles, a security relearn procedure (Passlock/VATS) or a Crankshaft Variation (CASE) relearn may be necessary after installation for the vehicle to start and run correctly. These are simple procedures that can often be done without a scan tool. We can provide instructions for these if they are required for your specific vehicle.
Is this a new or used part?
This is a genuine, used OEM (Original Equipment Manufacturer) part that has been sourced from a salvaged vehicle. It has been tested to ensure it is fully functional and is a reliable, cost-effective alternative to a brand-new module from a dealership.
Will this fix my vehicle’s problem for sure?
While this PCM will solve issues caused by a faulty computer, it’s essential to ensure your vehicle has been properly diagnosed. Problems like a bad sensor or wiring issue can sometimes mimic PCM failure. We recommend a thorough diagnosis by a qualified technician to confirm the PCM is the root cause of your issue.