Is Your Late 90s GM Truck or Van Running Poorly?
If you’re dealing with frustrating issues like stalling, erratic shifting, a persistent check engine light, or even a no-start condition in your 1998-1999 GM vehicle, a failing Powertrain Control Module (PCM) is a very likely culprit. The PCM is the central computer of your vehicle, managing everything from fuel injection and spark timing to transmission shift points. When it starts to fail, it can cause a cascade of problems that are often misdiagnosed, leading to wasted time and money on unnecessary parts.
This is a genuine, used GM PCM that has been meticulously tested and is ready to be programmed specifically for your vehicle. We take your vehicle’s VIN and flash the module with the latest, most stable software updates from General Motors. This ensures optimal performance, fuel economy, and emissions, essentially giving your vehicle’s brain a fresh start. This is not a generic, one-size-fits-all solution; it’s a tailored fix for your exact truck or van.
From the Diagnostic Bay
I remember a customer with a ’99 Chevy Tahoe who was at his wit’s end. The truck had a nasty, intermittent misfire and would sometimes refuse to shift out of second gear. He had already replaced the spark plugs, wires, cap, rotor, and even the transmission speed sensor, all to no avail. The codes were all over the place—misfire codes, transmission communication codes, O2 sensor codes. After confirming all the wiring was intact, we suspected the PCM. The internal drivers that control the ignition coil and communicate with the transmission were failing. We installed a VIN-programmed PCM just like this one, performed the security relearn, and the truck ran like it just rolled off the assembly line. All the ghost codes vanished, and the shifting was crisp and smooth. It’s a classic case of the brain, not the body, being the problem.
Symptoms of a Failing GM PCM
- ✔ Persistent Check Engine Light (CEL) with communication-related trouble codes (e.g., U-codes).
- ✔ Engine stalls unexpectedly or struggles to start.
- ✔ Rough idling, hesitation, or misfires that don’t resolve with a standard tune-up.
- ✔ Noticeable decrease in fuel efficiency.
- ✔ Harsh, delayed, or incorrect automatic transmission shifting.
- ✔ The vehicle’s anti-theft system (PassLock/VATS) engages randomly, preventing startup.
- ✔ Complete no-start condition where the engine cranks but won’t fire.
The Right Solution for Your 1998-1999 GMC 1500 PCM
Replacing the PCM on these GMT400 and related platform vehicles is a straightforward process, but it requires the correct programming to function. Bypassing this step with a simple junkyard swap will result in a no-start condition due to the vehicle’s anti-theft system. Our service eliminates this headache. By programming the module to your VIN before it ships, we ensure the unit is ready for installation. Once installed, the only remaining step is a simple security relearn procedure that you can perform yourself in your driveway—no expensive scan tools or dealer visits required.
This module is a direct replacement for multiple part numbers, including 09355699, 16266645, 16250279, 16258815, and 09366810. It fits a wide range of popular GM models from 1998-1999, such as the Chevrolet & GMC 1500/2500/3500 Pickups, Tahoe, Yukon, Suburban, Express, Savana, and more. Please verify your part number and consult the fitment list to ensure compatibility.
Frequently Asked Questions
What exactly is VIN programming?
VIN programming involves loading the specific software and calibrations for your vehicle’s engine, transmission, and options onto the PCM. We use your 17-digit Vehicle Identification Number (VIN) to access the correct GM factory file, ensuring the computer works perfectly with your truck.
How do I provide my VIN?
After you complete your purchase, please send us a message with your vehicle’s VIN. We cannot ship the module until we receive this information, as the programming is the most critical step.
Is this part difficult to install?
No, the physical installation is simple. It typically involves disconnecting the battery, unplugging the electrical connectors from the old PCM, unbolting it from its bracket in the engine bay, and then doing the reverse to install the new one. The final step is a 30-minute security relearn procedure which we can provide instructions for.
Do I need to send my old computer back?
No, there is no core charge or need to return your old, faulty module. You can keep it or dispose of it as you see fit.
This is a used part. How can I be sure it works?
Each module is sourced from a salvaged vehicle and undergoes testing to ensure the hardware is fully functional before we perform any programming. This provides a reliable and cost-effective solution compared to a much more expensive new part from a dealer.