Is Your GM Truck or Van Running Rough?
If your late-90s Chevrolet Express, GMC Savana, or another GM truck is suffering from erratic behavior, poor fuel economy, or a persistent check engine light, the Powertrain Control Module (PCM) could be the culprit. As the central command center for your vehicle’s engine and transmission, a failing PCM can cause a cascade of frustrating and difficult-to-diagnose issues. This isn’t just an inconvenience; it’s a critical component failure that can leave you stranded. This replacement engine computer, part number 16258815, is the definitive solution to restore your vehicle’s performance and reliability.
From the Diagnostic Bay
I once had a 1998 Chevy K2500 in the shop with a classic no-start, no-communication issue. The owner had already replaced the fuel pump and ignition coil based on advice from a parts store. When we hooked up our scanner, we couldn’t communicate with the PCM at all. Before condemning the computer, we did the basics: checked all fuses and power/ground connections to the PCM. We found a corroded ground wire on the engine block, a very common issue on these GMT400 platform trucks. After cleaning and re-securing the ground, the truck fired right up. Always check your main power and grounds before replacing a PCM—it can save you hundreds of dollars and a lot of headaches.
The Critical Role of a Programmed 1998-1999 Express 3500 PCM
The PCM in your 1998-1999 GM vehicle is more than just a simple computer; it’s the brain of the entire powertrain. It constantly analyzes data from dozens of sensors—like the crankshaft position sensor, throttle position sensor, and oxygen sensors—to make real-time adjustments. It precisely controls fuel injector pulse width, ignition timing, and transmission shift points to ensure optimal power, efficiency, and emissions. When it fails, the entire system is compromised. Our service takes the guesswork out of the repair. We flash this genuine, used GM PCM with the latest factory software updates specifically for your vehicle’s VIN. This ensures it communicates perfectly with all other modules and operates exactly as the manufacturer intended.
Common Symptoms of a Failing GM PCM
- ✔ Check Engine Light: A constant or flashing check engine light, often with communication error codes (U-codes) or internal processor fault codes (P06xx series).
- ✔ No-Start or Hard Starting: The engine cranks but refuses to start, or takes an excessive amount of time to fire up, either hot or cold.
- ✔ Poor Engine Performance: Noticeable loss of power, hesitation during acceleration, stumbling, or misfiring.
- ✔ Erratic Shifting or Transmission Issues: Harsh shifting, delayed engagement into gear, or getting stuck in a single gear (limp mode).
- ✔ Reduced Fuel Economy: A sudden and unexplained drop in your vehicle’s gas mileage.
- ✔ Stalling: The engine randomly shuts off while driving or when coming to a stop.
- ✔ Intermittent Problems: Issues that appear and disappear, often related to temperature changes or vehicle vibration.
A Simple, Plug-and-Play Solution
Don’t let a faulty computer keep your reliable truck off the road. This replacement 1998-1999 Express 3500 PCM is a cost-effective and straightforward solution. We handle the complex part—the programming. All you need to do is provide us with your vehicle’s VIN at checkout. We will then program the module, so it arrives ready for installation. In most cases, installation is as simple as disconnecting the battery, locating and swapping the module, and reconnecting the battery. This eliminates the need for expensive dealership visits and specialized programming tools. Get your truck or van running smoothly again with a reliable, pre-programmed PCM.
Frequently Asked Questions
Do I need to do any programming after I receive this PCM?
No. We program the PCM with your vehicle’s specific VIN before shipping. It will arrive ready to install. However, on some GM vehicles, you may need to perform a simple security relearn procedure, which can typically be done without any special tools and takes about 30 minutes. Instructions are readily available online for this process.
Where do I provide my vehicle’s VIN?
Please enter your 17-digit Vehicle Identification Number (VIN) during the checkout process or send it to us via email after placing your order. This is crucial for us to program the module correctly for your specific vehicle configuration.
Is this a new part?
No, this is a thoroughly tested and inspected, genuine used OEM part sourced from a salvaged vehicle. We ensure it is fully functional before programming and shipping. This provides OEM quality and reliability at a fraction of the cost of a new unit.
Will this fix my vehicle’s problem for sure?
While this PCM will solve issues caused by a faulty computer, it’s essential to ensure your vehicle has been properly diagnosed. A PCM failure can mimic other issues like a bad sensor, wiring problems, or fuel delivery faults. We recommend a professional diagnosis to confirm the PCM is the root cause of your problem.
What if I order the wrong part?
Please use the comprehensive fitment list on this page and match the part number (16258815 or one of the interchangeable numbers like 09355699) to your original module. If you are unsure, contact us with your VIN before ordering, and we will be happy to verify compatibility for you.