Is Your Workhorse Van Suddenly Unreliable?
If your 1998 Chevrolet Express 2500 is giving you headachesโstalling at stoplights, refusing to start, or showing a persistent Check Engine Lightโthe problem often points directly to a failing Powertrain Control Module (PCM). As the central computer for your engine and transmission, its health is critical. After two decades of heat cycles and vibrations under the hood, the internal electronic components can begin to break down, leading to a host of frustrating and hard-to-diagnose issues.
Over my 20+ years in the shop, I’ve seen countless GM trucks and vans from this era with symptoms that leave owners and even other mechanics stumped. They’ll chase vacuum leaks, replace sensors, and swap spark plugs, but the root cause is often a failing PCM driver circuit or corrupted software. This isn’t just a part failure; it’s a communication breakdown at the heart of your vehicle.
The Tell-Tale Signs of a Failing GM PCM
A faulty PCM doesn’t always fail completely. It often starts with intermittent problems that can be maddening to pinpoint. If you’re experiencing any of these, your PCM is the prime suspect:
- โ Unexplained Check Engine Light, especially with communication error codes (U-codes) or random misfire codes (P0300).
- โ Your van cranks but refuses to start, even with good fuel pressure and spark.
- โ Harsh or erratic automatic transmission shifting.
- โ A noticeable drop in fuel economy.
- โ The engine stalls unexpectedly while driving or idling.
- โ Inaccurate or non-functioning gauges on the instrument cluster.
Expert Pro Tip: The Critical Post-Installation Step
After installing this PCM, you must perform a Crankshaft Position System Variation Learning Procedure, also known as a CASE Relearn or Crank Relearn. Without this, the PCM cannot accurately detect engine misfires, and you will likely have a persistent P1336 trouble code. While some high-end scan tools can initiate this procedure, the most common method involves accelerating the vehicle to fuel cut-off (around 4,000-5,000 RPM) under specific conditions. We highly recommend having a qualified technician with the proper scan tool perform this to ensure it’s done correctly and safely.
The Plug-and-Play Solution: Programmed & Ready to Install
This isn’t just a replacement part; it’s a complete, hassle-free solution. We take a fully tested, reliable Powertrain Control Module and program it specifically for YOUR 1998 Express 2500 using the Vehicle Identification Number (VIN) you provide. This critical step ensures:
- โ Perfect Compatibility: The module is loaded with the correct GM factory software for your van’s specific engine, transmission, and options.
- โ Latest Updates: We flash it with the newest software updates from GM, which can resolve factory bugs and improve performance and drivability.
- โ No Dealer Required: You skip the expensive trip to the dealership for programming. This module is ready for installation right out of the box.
Guaranteed Fitment & Part Number Compatibility
This module is a direct replacement for service part number 16250279 and is also fully compatible with part numbers 09366810 and 09355699. It is designed for a wide range of 1998-1999 General Motors trucks, vans, and SUVs. Please verify the part number on your original module to ensure a perfect match. The installation is straightforward for anyone with basic mechanical skills. On your Express Van, the PCM is located in the engine compartment on the driver’s side. Simply disconnect the battery, carefully unplug the connectors from the old module, unbolt it, and install the new one in its place. Once reconnected, perform the CASE relearn, and you’ll be back on the road with a reliable vehicle.