Is Your GM Truck or Van Running Rough?
If your 1998-1999 Chevrolet Express, GMC Savana, or other compatible GM vehicle is experiencing frustrating issues like stalling, erratic shifting, a persistent check engine light, or a no-start condition, a failing Powertrain Control Module (PCM) is often the culprit. The PCM is the central computer of your vehicle, managing everything from fuel injection and spark timing to transmission shift points. When it fails, the symptoms can be widespread and difficult to diagnose. Don’t let a faulty computer keep you off the road. This is your direct-fit, reliable solution.
From the Diagnostic Bay
We had a 1999 Suburban in the shop that was driving the owner crazy. It had an intermittent stalling problem that no one could figure out. The owner had already replaced the fuel pump, crank sensor, and ignition coil based on advice from various forums. When we hooked up our professional scan tool, we noticed the data stream from the PCM would freeze just before the engine cut out. We swapped in a known-good, programmed PCM, and the truck ran perfectly. It’s a classic case where chasing individual sensors costs more time and money than addressing the root cause: the computer itself.
Your Plug-and-Play 1998-1999 Express PCM Solution
This isn’t just a replacement part; it’s a complete service. We take a tested, genuine OEM computer and professionally program it to your vehicle’s specific Vehicle Identification Number (VIN). This critical step ensures that the module communicates perfectly with your vehicle’s engine, transmission, and security systems. We flash it with the latest software updates available from General Motors, which can resolve common drivability issues and improve overall performance and efficiency. This means you get a component that is often better than the one that originally came in your truck.
Common Symptoms of a Failing PCM:
- ✔ Check Engine Light is on with various trouble codes (DTCs)
- ✔ Engine stalls, misfires, or runs poorly
- ✔ Harsh or erratic automatic transmission shifting
- ✔ Vehicle won’t start, even with a good battery and starter
- ✔ Noticeable decrease in fuel economy
- ✔ Failure to pass emissions testing
- ✔ Loss of communication with the OBD-II port
Simple Installation Process
Replacing the PCM is a straightforward job for a DIY mechanic or any professional technician. In most of these GM trucks and vans (like the Express, Tahoe, and pickups), the module is located in the engine compartment on the driver’s side. After disconnecting the battery, simply unbolt the mounting bracket, carefully unplug the electrical connectors, and swap in the new unit. Once installed, a security relearn procedure may be required, which can often be performed without special tools. This ensures your vehicle starts and runs correctly with its new ‘brain’.
This module is a direct replacement for multiple part numbers, including 09355699, 16266645, 16250279, 16258815, and 09366810. Please verify the extensive fitment list to ensure compatibility with your specific vehicle model and options.
Frequently Asked Questions
Do I need to program this computer?
No. We handle all the programming for you before shipment. Simply provide us with your vehicle’s 17-digit VIN during or after checkout, and we will flash the module with the correct software for your exact vehicle. It will arrive ready to install.
Is this a new part?
This is a high-quality, used OEM (Original Equipment Manufacturer) computer sourced from a salvaged vehicle. Each unit is thoroughly inspected and tested to ensure it functions correctly before being programmed and shipped.
Where is the PCM located on my 1999 Chevy truck?
On most 1998-1999 GM full-size trucks and vans like the Express, Suburban, Tahoe, and C/K Pickups, the PCM is located in the engine compartment, typically on the driver’s side near the firewall or inner fender.
Will I need to do anything after I install it?
In many cases, the vehicle will start and run immediately. However, you may need to perform a security relearn procedure (often called a Passlock relearn) or a Crankshaft Variation Relearn (CASE relearn). These procedures are straightforward and instructions can be readily found online or in a service manual.
How do I find my VIN?
Your 17-digit Vehicle Identification Number (VIN) can be found on your vehicle’s registration, insurance card, or on a metal plate on the driver’s side of the dashboard, visible through the windshield.