Is Your GM Truck or Van Plagued by Mysterious Issues?
If your 1998-1999 Chevrolet Express, GMC Savana, or other compatible GM vehicle is suffering from erratic behavior like stalling, poor shifting, a persistent check engine light, or a no-start condition, the root cause is often a failing Powertrain Control Module (PCM). As the central computer, the PCM manages everything from fuel injection and ignition timing to transmission shift points. When it malfunctions, it can create a cascade of frustrating and difficult-to-diagnose problems.
From the Diagnostic Bay
I once had a 1999 Suburban in the shop that was driving the owner crazy. He had replaced the throttle position sensor, the mass air flow sensor, and even the fuel pump based on various codes and advice. The truck would still randomly stall at red lights and shift hard between first and second gear. After confirming all the new parts were working, we hooked up our high-level scanner and found the PCM was intermittently dropping communication. A replacement, VIN-programmed PCM like this one solved every single issue in one go. It’s a reminder that sometimes the ‘brain’ is the real culprit, not the parts it’s controlling.
Common Symptoms of a Failing PCM
- ✔ Persistent Check Engine Light (CEL) with codes related to module communication or sensor circuits.
- ✔ Engine stalling, stumbling, or running rough for no apparent reason.
- ✔ Harsh, erratic, or delayed automatic transmission shifting.
- ✔ A complete no-start condition where the engine cranks but won’t fire up.
- ✔ Noticeable decrease in fuel economy.
- ✔ Failure to pass an emissions or smog test.
- ✔ Inability for a diagnostic scan tool to communicate with the module.
The Direct-Fit Solution: A Pre-Programmed 1998-1999 Express 3500 Van PCM
Don’t just buy a used computer from a salvage yard and hope for the best. This genuine used GM PCM is the definitive solution for your vehicle. We take the guesswork out of the repair by pre-programming the module specifically for your truck or van using the VIN you provide. This critical step ensures that the computer has the correct software and calibrations for your vehicle’s specific engine, transmission, and options. It also loads the latest available updates from General Motors, which can resolve factory-known bugs and improve performance and reliability. This service saves you a costly trip to the dealership for programming.
This module is a direct replacement for multiple part numbers, including 16258815, 09355699, 16266645, and 9366810. By matching the programming to your VIN, we ensure perfect compatibility and function, restoring your vehicle’s original performance and dependability.
Installation Note:
After installing the programmed module, you may need to perform a simple security relearn procedure (often called Passlock or Passkey relearn). This procedure syncs the new PCM with your vehicle’s anti-theft system and can typically be done in your driveway in about 30 minutes with just the ignition key. Instructions are widely available online for your specific model.
Frequently Asked Questions
What is a PCM and what does it do?
The Powertrain Control Module (PCM) is your vehicle’s main computer. It controls all aspects of the engine and transmission to ensure optimal performance, fuel efficiency, and emissions.
Why do you need my VIN?
Your Vehicle Identification Number (VIN) allows us to program the PCM with the exact software and calibration file for your vehicle’s specific engine, transmission, and factory options. This ensures it works perfectly right out of the box.
Is this part truly plug-and-play?
Because we program it to your VIN, it is electronically plug-and-play. However, you will likely need to perform a simple, 30-minute security relearn procedure at home so the module can sync with your vehicle’s anti-theft system.
Where is the PCM located on my vehicle?
On most of these GM trucks, vans, and SUVs, the PCM is located in the engine compartment, typically on the driver’s side fender well or near the battery.
Will this fix my check engine light?
If the check engine light is caused by a faulty PCM, then yes, this will resolve the issue. It is crucial to properly diagnose the problem before ordering to ensure the PCM is the part you need.