Restore Your Van’s Reliability and Performance
As a technician with two decades of experience, I’ve seen countless work vans and trucks sidelined by frustrating, hard-to-diagnose electrical issues. If your 1998-1999 Chevrolet Express 1500 is stalling, running rough, shifting erratically, or simply won’t start, a failing Powertrain Control Module (PCM) is a very likely culprit. This isn’t just an inconvenience; it’s lost time and money. This genuine used GM PCM is your direct, cost-effective solution to get your vehicle back in service, fast.
The PCM is the brain of your engine and transmission, controlling everything from fuel mixture and spark timing to transmission shift points. When it fails, it can create a cascade of problems that are often misdiagnosed. Instead of throwing parts at the problem, address the source with a reliable replacement. We make the process simple: this module is professionally flashed with the latest GM software updates and programmed specifically to your vehicle’s VIN before it ships. It arrives at your door ready for installation, with no dealership visit required for programming.
A Technician’s Notebook: The Intermittent No-Start
I remember a ’99 Savana that came into the bay on a tow truck. The owner, a contractor, was at his wit’s end. It would run fine for weeks, then suddenly refuse to start. He’d already replaced the battery, starter, and fuel pump on the advice of other shops. After hooking up my scanner, I saw no communication with the PCM. A quick wiggle of the main connector and it came back to life, but testing revealed internal circuit board failure. Heat soak was causing an open circuit inside the module. We installed a VIN-programmed PCM just like this one, and that van was back on the job reliably the next day. It’s a classic failure mode for these units, and this is the definitive fix.
Is Your Vehicle Showing These Symptoms?
- ✔ Check Engine Light is on with seemingly random codes, or communication error codes like P0601 or P0605.
- ✔ The engine cranks but refuses to start.
- ✔ Unexplained drops in fuel economy.
- ✔ Rough or erratic idling and stalling.
- ✔ Harsh or incorrect automatic transmission shifting.
- ✔ Failing a state emissions inspection due to module-related faults.
A Straightforward Guide to Installation
Replacing the 1998-1999 Express 1500 PCM is a job most DIYers can handle with basic tools. Just follow these steps for a smooth installation.
- Safety First: Disconnect the negative terminal from your vehicle’s battery to prevent any electrical shorts.
- Locate the PCM: On most Express/Savana vans, the PCM is located in the engine compartment, typically on the driver’s side near the battery or on the fender well.
- Disconnect the Connectors: Carefully unclip the wiring harness connectors from the old PCM. These connectors have locking tabs; be gentle to avoid breaking them.
- Remove the Old Module: Unbolt the old PCM from its mounting bracket. Keep the hardware as you will need it for the new module.
- Install the New PCM: Mount your new, pre-programmed PCM onto the bracket using the original hardware.
- Reconnect Everything: Firmly plug the wiring harnesses back into the new module until they click into place. Reconnect the negative battery terminal.
- Security Relearn (If Necessary): In many cases, the vehicle will start and run perfectly. Some GM vehicles may require a simple security relearn procedure, which typically involves turning the key to the ‘ON’ position for 10-15 minutes. Consult your owner’s manual for specific steps if needed.
Will This Fit My GM Truck or Van?
This module is a direct replacement for several part numbers, including 16250279, 09355699, 16266645, 16258815, and 09366810. It is guaranteed to fit the following vehicles with service ID 9355699:
- ✔ 1998-1999 Chevrolet & GMC 1500/2500/3500 Pickups (Gasoline)
- ✔ 1998-1999 Chevrolet Express & GMC Savana 1500/2500/3500 Vans (Gasoline)
- ✔ 1998-1999 Chevrolet Suburban 1500/2500 (Gasoline)
- ✔ 1998-1999 Chevrolet Tahoe & GMC Yukon (Gasoline)
- ✔ 1999 Cadillac Escalade
- ✔ 1998 Chevrolet Astro & GMC Safari
- ✔ 1998 Oldsmobile Bravada, GMC Envoy, Chevrolet S10 Blazer, GMC S15 Jimmy
- ✔ 1998 Chevrolet S10, GMC Sonoma, Isuzu Hombre (4.3L V6)
Frequently Asked Questions
Do I need to do anything after I buy it?
Yes. After your purchase, you must send us your vehicle’s 17-digit VIN. We cannot ship the module until we have your VIN to program it correctly.
Is this part new?
No, this is a high-quality, tested used part sourced from a salvaged vehicle. This allows us to offer a reliable, cost-effective solution.
Will I need a mechanic to install this?
No dealership programming is required. Because we flash it to your VIN, it’s a plug-and-play installation for anyone comfortable with basic hand tools. Some vehicles may require a simple key-cycle security relearn procedure.
What if my part number isn’t an exact match to 16250279?
This module is a direct replacement for a range of part numbers, including 09355699, 16266645, 9355699, 16258815, and others listed. As long as your vehicle is on the compatibility list, this module will work.
What does ‘flashed with the newest updates’ mean?
It means we load the module with the most current software available from GM for your specific vehicle. This can correct drivability issues and improve performance over the original software that was in your old PCM.