Is your 1998 or 1999 GM truck or van suffering from perplexing issues like stalling, erratic shifting, or a no-start condition? These frustrating problems often point to a failing Powertrain Control Module (PCM), the central computer that manages your vehicle’s engine and transmission. A faulty PCM can disrupt critical functions, leading to poor performance, decreased fuel economy, and a persistent Check Engine Light. Don’t let a bad computer keep your reliable truck off the road. This replacement module is the definitive solution to restore your vehicle’s operational integrity.
This is a genuine, used OEM PCM, service number 9355699, sourced from a salvaged vehicle and rigorously tested for full functionality. The key to our service is the professional programming we perform before shipping. Simply provide us with your vehicle’s VIN after purchase, and our technicians will flash the module with the latest, most stable software updates directly from GM. This ensures that the computer is a perfect match for your vehicle’s specific configuration, including engine size, transmission type, and emissions equipment. This process eliminates the need for an expensive trip to the dealership for programming.
Diagnosing a Faulty 1998-1999 Chevrolet PCM
A failing engine computer can manifest in numerous ways, often mimicking other sensor or component failures. If you’ve checked the basics and are still stumped, it’s time to consider the PCM as the culprit. This module is the core of your vehicle’s electronic system, and its failure can have widespread effects. Replacing your old unit with our correctly programmed 1998-1999 Chevrolet PCM is the most effective way to resolve these deep-seated electronic issues and restore dependable operation.
From the Diagnostic Bay
We recently worked on a ’99 Chevy Tahoe that had its owner at his wit’s end. The truck would start and run fine for about 20 minutes, then suddenly stall and refuse to restart for an hour. The owner had replaced the fuel pump, ignition coil, and crank sensor with no luck. When we hooked up our professional scan tool, we noticed the PCM would lose communication right before the stall. It was overheating internally and shutting down. We installed one of our pre-programmed 9355699 modules, performed the quick security relearn, and the Tahoe ran perfectly. It’s a classic failure mode for these units after decades of heat cycles.
Common Symptoms of PCM Failure
- ✔ No-start or intermittent starting problems
- ✔ Engine stalling unexpectedly while driving or at idle
- ✔ Harsh or erratic automatic transmission shifting
- ✔ A significant, unexplained drop in fuel mileage
- ✔ Check Engine Light is on with communication error codes (like P0601-P0606)
- ✔ Misfire codes that persist after replacing plugs, wires, and coils
- ✔ Failure to communicate with a diagnostic scan tool
This module is a direct fit for a wide range of General Motors vehicles from 1998-1999, including Chevrolet and GMC pickups, Suburbans, Tahoes, Yukons, and Express/Savana vans. Please verify that your original module carries the part number 9355699 or one of the compatible numbers listed (16266645, 16250279, 16258815, 09366810) to ensure perfect compatibility. Installation is straightforward, though a security relearn procedure (also known as a CASE learn) may be required, which can be done without special tools. Instructions for this procedure are widely available online or in service manuals.
Frequently Asked Questions
What is a PCM and what does it do?
The Powertrain Control Module (PCM) is your vehicle’s main computer. It controls all aspects of engine performance, fuel delivery, ignition timing, and automatic transmission shifting to ensure optimal power, efficiency, and emissions.
Do I need to do anything after installing this PCM?
Because this PCM is programmed to your VIN, it is nearly a plug-and-play installation. However, on many GM vehicles, you will need to perform a simple security relearn procedure. This syncs the new PCM with your vehicle’s anti-theft system and can typically be done in your driveway in about 30 minutes without any special tools.
How do I provide my Vehicle Identification Number (VIN)?
After you complete your purchase, simply send us a message with your 17-digit VIN. We cannot program and ship your module until we receive this information. Your VIN is typically found on your driver’s side dashboard (visible through the windshield) or on the driver’s side door jamb sticker.
Is this a new part?
No, this is a genuine, used OEM part that has been carefully removed from a salvaged vehicle. We test each unit to ensure it is fully functional before programming and shipping it to you.
Will this fix my check engine light?
If the check engine light is caused by an internal failure of your old PCM (indicated by codes like P0601, P0605, etc.), then this replacement module will solve the problem. However, if the light is on due to a faulty sensor or other component, you will still need to repair that underlying issue.