Is Your GM Truck or Van Acting Up? The PCM Might Be the Culprit.
If you’re driving a 1998-1999 Chevrolet, GMC, or Cadillac truck or van, you own a legend. But even legends can develop puzzling electrical and performance issues. Often, the root cause isn’t a mechanical failure but a problem with the brain of the operation: the Powertrain Control Module (PCM). This computer controls everything from fuel injection and spark timing to transmission shifting and emissions. When it starts to fail, it can cause a cascade of frustrating symptoms that are difficult to diagnose. This is a direct, reliable solution to get your vehicle back on the road and running smoothly.
From the Diagnostic Bay
We had a ’99 Tahoe in the shop that was driving the owner crazy. It would randomly stall at stoplights, shift hard from first to second, and the check engine light would come and go with no consistent codes. The owner had already replaced the fuel pump and a handful of sensors with no luck. After checking all the wiring and grounds, we hooked up our high-level scanner and noticed the PCM was intermittently losing communication. We swapped in a pre-programmed PCM like this one, performed the quick security relearn, and the Tahoe ran like it just rolled off the assembly line. It’s a classic case of PCM failure that mimics a dozen other problems.
Common Symptoms of a Failing 1998-1999 Chevrolet PCM
- ✔ Check Engine Light is on with seemingly random or communication-related trouble codes (e.g., U-codes).
- ✔ Your vehicle fails to start or stalls intermittently for no apparent reason.
- ✔ Noticeable decrease in fuel economy.
- ✔ The automatic transmission is shifting erratically, harshly, or getting stuck in one gear (limp mode).
- ✔ The engine misfires, runs rough, or hesitates during acceleration.
- ✔ Failure to pass an emissions test due to monitor readiness issues.
- ✔ Gauges on the instrument cluster stop working or behave erratically.
The Plug-and-Play Solution You Need
Don’t waste time and money chasing phantom issues or paying for expensive dealership diagnostics. This is a genuine, used OEM PCM that has been rigorously tested and confirmed to be fully functional. The real value is in our programming service: when you purchase this module, you provide us with your vehicle’s VIN. We then flash the computer with the latest, most stable software updates directly from GM for your specific vehicle configuration. This ensures optimal performance, fuel efficiency, and transmission function. It arrives at your door ready for installation, eliminating the need for a trip to the dealer for expensive programming.
This unit is a direct replacement for part number 09355699 and is also compatible with several other service numbers, including 16266645, 9355699, 16250279, 16258815, 09366810, and 9366810. It fits a wide range of popular GM models from the era, such as the Chevrolet Silverado, Suburban, Tahoe, Express Van, GMC Sierra, Yukon, Savana Van, Cadillac Escalade, and more. Please verify the part number and check the detailed fitment list to ensure compatibility.
Frequently Asked Questions
Do I need to get this PCM programmed?
No. This PCM comes fully programmed to your vehicle’s specific VIN before it ships. All you need to do is provide us with your VIN after purchase. It’s a plug-and-play solution.
What is the security relearn procedure?
After installation, you may need to perform a simple security relearn, also known as a VATS relearn. This syncs the new PCM with your vehicle’s anti-theft system. The process is easy: 1) Turn the key to the ‘ON’ position (don’t start the engine). 2) Leave it on for 10-12 minutes, or until the ‘Security’ light on the dash turns off. 3) Turn the key off for 10 seconds. 4) Repeat the cycle two more times. After the third cycle, the vehicle should start and run normally.
Is this a new part?
This is a high-quality, used OEM part sourced from a salvaged vehicle. Each unit is thoroughly tested to ensure it meets or exceeds original factory standards for performance and reliability. Using a genuine OEM part guarantees perfect fitment and communication with your vehicle’s other modules.
Where can I find my vehicle’s VIN?
Your 17-digit Vehicle Identification Number (VIN) can be found in a few places: on a metal plate on the driver’s side of the dashboard (visible through the windshield), on the driver’s side door jamb sticker, or on your vehicle’s registration and insurance documents.
Will this fix my truck’s problem for sure?
This module is a direct replacement for a faulty PCM and will solve problems caused by a failing unit. However, it’s crucial to ensure your vehicle has been properly diagnosed. This part will not fix issues related to bad wiring, faulty sensors, or other mechanical problems. If you’ve confirmed the PCM is the issue, this is the solution you need.