Restore Peak Performance to Your GM Truck or Van
Is your 1998-1999 Chevrolet 3500 Pickup running rough, shifting erratically, or showing a persistent check engine light? These are classic signs of a failing Powertrain Control Module (PCM). The PCM is the electronic brain of your vehicle, managing critical functions like fuel delivery, ignition timing, transmission shifting, and emissions. When it starts to fail, it can cause a cascade of frustrating and difficult-to-diagnose problems. This genuine OEM engine computer, part number 16250279, is the definitive solution to get your truck back on the road and running like it should.
We take the guesswork out of the repair. Unlike a generic part from a local store, this PCM is specifically programmed to your truck’s unique Vehicle Identification Number (VIN). This ensures seamless communication with all other modules in your vehicle, correct engine and transmission parameters, and adherence to factory specifications. We flash it with the latest GM-certified software updates, which can often resolve issues that were present even when the truck was new. This is not just a replacement part; it’s a restoration of your vehicle’s core operational logic.
From the Diagnostic Bay
We had a ’99 Suburban come in that had been to three different shops. The owner had replaced the throttle position sensor, the MAF sensor, and even the fuel pump, but it still had a terrible hesitation off the line and would stall intermittently. The codes were all over the place. After confirming all the new parts were working, we scoped the PCM’s outputs and found erratic signals to the injectors. We installed one of our VIN-programmed PCMs, performed the quick security relearn, and the truck ran perfectly. It’s a classic case where chasing symptoms costs more time and money than addressing the root cause—the failing computer.
Diagnosing a Faulty 1998-1999 Chevy 3500 PCM
A failing engine computer can manifest in numerous ways, often mimicking other component failures. If you’re experiencing any of the following, your PCM is a likely culprit:
- ✔ Check Engine Light: The light is on, and you may have codes related to sensors, emissions (like P0420), or internal module failure (like P0601-P0606).
- ✔ Poor Engine Performance: Noticeable loss of power, hesitation during acceleration, rough idling, or engine stumbling.
- ✔ Reduced Fuel Economy: A sudden and unexplained drop in your MPG is a strong indicator that the air/fuel mixture is not being managed correctly.
- ✔ Transmission Issues: Harsh shifting, delayed engagement, or getting stuck in a single gear (limp mode) can be caused by the PCM, which controls modern automatic transmissions.
- ✔ Intermittent or No-Start Condition: The engine cranks but won’t start, or it starts unpredictably. This can be due to the PCM not firing the ignition coils or fuel injectors.
- ✔ Communication Errors: Your diagnostic scan tool cannot communicate with the PCM, a definitive sign of an internal failure.
Plug-and-Play Solution with Simple Relearn
Our goal is to make this repair as straightforward as possible. By programming the module to your VIN before it ships, we handle the most complex part of the job. When you receive the unit, the installation is simple:
- Disconnect the Battery: Always disconnect the negative battery terminal before working on any vehicle electronics.
- Locate and Replace the PCM: On most of these trucks and vans, the PCM is located in the engine bay, typically on the driver’s side fender. Disconnect the wiring harnesses and unbolt the old unit. Bolt the new one in its place and reconnect the harnesses.
- Perform Security Relearn: After reconnecting the battery, you will likely need to perform a simple security relearn procedure (often called Passlock or CASE relearn). This syncs the new PCM with your vehicle’s anti-theft system and can usually be done in your driveway with just the ignition key. Instructions are widely available online for your specific model.
This unit is a direct replacement for multiple service numbers, including 09355699, 16266645, 9355699, 16250279, 16258815, 09366810, and 9366810. It fits a massive range of 1998-1999 GM vehicles, from the Chevrolet and GMC full-size pickups (1500, 2500, 3500) to the Tahoe, Suburban, Yukon, Express, Savana, and even the S10/Blazer platform. Please verify your part number or contact us with your VIN to confirm compatibility.
Frequently Asked Questions
Do I need to have this computer programmed?
No. We handle all the programming for you before we ship the part. Simply provide us with your vehicle’s VIN during or after checkout, and we will flash the module with the correct factory software and updates for your specific vehicle.
Is this a simple plug-and-play installation?
It is a direct-fit replacement, but you will likely need to perform a security relearn procedure after installation. This is a simple process that syncs the new computer to your vehicle’s anti-theft system and typically takes 10-30 minutes using only your ignition key.
What information do you need from me?
We need your 17-digit Vehicle Identification Number (VIN). This is essential for us to load the correct software for your truck’s engine, transmission, and options. You can find your VIN on your dashboard (visible through the windshield) or on your driver’s side door jamb sticker.
Is this a new part?
This is a proven, tested, and fully functional used OEM (Original Equipment Manufacturer) part. These genuine GM units are known for their durability and reliability, and we ensure they are in excellent working condition before programming and shipping.
Will this fix my transmission shifting problems?
In many cases, yes. The PCM is responsible for controlling the transmission’s shift points and line pressure. If your transmission issues are electronic in nature and not caused by an internal mechanical failure, a new PCM will often resolve them.