Is Your GM Truck or Van Acting Up? The PCM Might Be the Culprit.
If you’re dealing with frustrating issues like a no-start condition, erratic engine performance, harsh transmission shifting, or a check engine light that won’t go away, the problem might not be a sensor or a mechanical part. As a technician with over two decades of experience under the hood, I’ve seen countless owners replace part after part, only to find the root cause was a failing Powertrain Control Module (PCM). The PCM is the brain of your 1998-1999 Chevrolet Express 2500, and when it starts to fail, it can cause a cascade of confusing and expensive problems.
Real-World Diagnosis: “A customer’s 1999 Savana 2500 came in last month with an intermittent no-start and a code for a bad crank sensor, which he had already replaced twice. After checking the wiring, we hooked up our scope and saw the 5-volt reference signal from the PCM was dropping out randomly. A new, properly programmed PCM fixed it instantly. It’s a classic failure mode I’ve diagnosed on hundreds of these GM Vortec-era vehicles.”
The Smart Solution: A VIN-Programmed PCM Ready for Installation
Forget the hassle and high cost of a dealership visit. This is a reliable, tested, used OEM Powertrain Control Module that we program specifically for your vehicle before it ever leaves our shop. You provide us with your vehicle’s VIN, and we flash the unit with the latest official GM software updates. This not only ensures compatibility but often corrects drivability and performance issues that were present in the original factory programming.
- ✔ VIN-Programmed for You: Arrives flashed with the newest GM calibration for your exact vehicle.
- ✔ Solves Common Issues: A direct fix for no-start, rough idle, poor fuel economy, and transmission control faults.
- ✔ No Dealer Required: This module is prepared to be plug-and-play, saving you hundreds in programming fees.
- ✔ Broad Compatibility: This unit, identified by part number 9366810, directly replaces several other part numbers, including 09355699, 16266645, and more, across a wide range of GM trucks and vans.
Simple Installation for Your 1998-1999 Express 2500 PCM
Replacing the PCM is a straightforward job you can do with basic hand tools. Follow these steps to get your vehicle back on the road quickly.
- Safety First: Disconnect the negative terminal from your vehicle’s battery.
- Locate the PCM: On most Express and Savana vans, the PCM is located in the engine compartment on the driver’s side, near the battery or airbox.
- Disconnect Connectors: Carefully unplug the electrical connectors from the old module. Inspect the pins for any corrosion or damage. If you see any green or white buildup, clean it carefully with a small brush and electrical contact cleaner before proceeding.
- Remove the Old Module: Unbolt the old PCM from its mounting bracket.
- Install the New Module: Bolt your new, pre-programmed PCM into place.
- Reconnect Everything: Securely plug the electrical connectors into the new PCM. You should hear a click. Reconnect the negative battery terminal.
- Final Check: Turn the key to the ‘On’ position for 10-15 seconds before starting the engine. This allows the system to initialize. Your vehicle is now ready to drive.
Confirming Your Fitment
This module is a guaranteed fit for a wide array of 1998 and 1999 GM vehicles that require service ID 9355699. This includes the Chevrolet Express, GMC Savana, Chevy/GMC Pickups (1500, 2500, 3500), Tahoe, Yukon, Suburban, and many others. By providing your VIN, you ensure we deliver a module that is perfectly matched to your engine, transmission, and factory options.