Is your reliable 1998 Chevrolet Express 1500 Van suddenly giving you trouble? If you’re dealing with a persistent check engine light, poor engine performance, or transmission issues, the problem often points to a failing Powertrain Control Module (PCM). As the central computer of your vehicle, the PCM is responsible for managing everything from fuel injection and ignition timing to transmission shifting. When it falters, your van’s performance and reliability suffer. This replacement PCM, part number 09355699, is the definitive solution to restore your vehicle’s factory operation and get you back on the road with confidence.
From the Diagnostic Bay
We had a 1999 GMC Safari van (which uses this exact same PCM) come into the shop with a maddening intermittent no-start condition. The owner had already replaced the fuel pump and crank sensor. It would run fine for days, then refuse to start, only to fire right up an hour later. After hours of chasing wires, we noticed the fuel pump relay wasn’t getting its ground signal from the PCM during the no-start events. A thermal test on the original PCM confirmed our suspicion: an internal driver circuit was failing when it got hot. We installed one of our VIN-programmed modules, and the van has been starting reliably ever since. It’s a classic example of how a failing PCM can mimic other component failures.
Diagnosing a Faulty 1998 Express 1500 PCM
A failing PCM can manifest in various ways, often mimicking other sensor or component failures. If your Express Van is experiencing any of the following, it’s a strong indicator that the main computer is the culprit:
- ✔ Persistent Check Engine Light (CEL) that won’t clear, often with communication-related trouble codes (U-codes).
- ✔ Unexplained engine stalling, especially after the vehicle has warmed up.
- ✔ Complete no-start condition where the engine cranks but won’t fire.
- ✔ Harsh, erratic, or delayed automatic transmission shifting.
- ✔ Noticeable decrease in fuel economy and overall engine power.
- ✔ Misfires, rough idling, or stumbling during acceleration.
- ✔ Failure to pass state emissions testing due to readiness monitor issues.
The Plug-and-Play Solution
Don’t let a complex computer repair intimidate you. We make this process straightforward. When you purchase this module, you simply provide us with your vehicle’s 17-digit VIN. Our technicians will then program the unit with the latest GM-certified software specific to your van’s configuration. This ensures perfect compatibility with your engine, transmission, and all factory options. The module arrives at your door ready for installation, requiring no additional programming or trips to the dealership. It’s a direct-fit replacement for part numbers 09355699, 16250279, and 09366810, and is compatible with a wide range of GM trucks and vans from the late 90s, as detailed in the fitment list.
Replacing the PCM is a manageable task for a DIY mechanic. It is typically located in the engine compartment on the driver’s side. Simply disconnect the negative battery terminal, carefully unplug the electrical connectors from the old module, unbolt it from its bracket, and install the new one in its place. Once connected and the battery is re-engaged, your vehicle will be ready to go. In some cases, a Crankshaft Variation Relearn (CASE Relearn) may be necessary to clear a P1336 trouble code, a procedure that can be performed with most professional-grade scan tools.
Frequently Asked Questions
What information do you need to program this PCM?
We require your vehicle’s 17-digit Vehicle Identification Number (VIN). You can typically find this on your driver’s side dashboard (visible through the windshield), on the driver’s door jamb sticker, or on your vehicle’s registration and insurance documents.
Is this a simple plug-and-play installation?
Yes, this module comes fully programmed to your VIN. In most cases, you can simply install it and start the vehicle. Occasionally, a security relearn or a CASE relearn procedure may be needed, which is a standard process for many automotive computer replacements.
Will this fix my transmission shifting problems?
If your shifting issues are caused by faulty signals or processing within the PCM, then yes, this replacement module will resolve them. The PCM controls transmission line pressure and shift points, so a failing unit is a very common cause of erratic shifting.
Does this module come with the latest software?
Absolutely. We flash each module with the newest updates available from GM for your specific VIN. This ensures any known bugs or drivability issues from the original software are corrected, often resulting in improved performance and efficiency.
Where is the PCM located on my 1998 Express Van?
On the 1998 Express and Savana vans, the Powertrain Control Module is typically located in the engine compartment, on the driver’s side, near the battery and firewall.