Get Your Workhorse Van Back on the Job
Is your 1998-1999 Chevrolet Express 3500 Van running rough, stalling, or refusing to start? A faulty Powertrain Control Module (PCM) is often the culprit behind these frustrating and costly issues. As the central computer of your vehicle, the PCM controls everything from fuel mixture and spark timing to transmission shifting. When it fails, your van’s performance and reliability suffer. This isn’t just an inconvenience; for a work vehicle like the Express 3500, downtime means lost income. We offer a dependable and straightforward solution: a tested, used OEM PCM that comes fully programmed to your van’s specific Vehicle Identification Number (VIN).
A Technician’s Notebook: The Intermittent Stall
I once had a local delivery company bring in their ’99 Express 3500 with a problem that was driving them crazy. The van would run perfectly for days, then suddenly stall at a stoplight and refuse to restart for 10-15 minutes. There were no consistent trouble codes, just a history of random misfires. After checking fuel pressure and ignition components, we hooked up a scope to the PCM outputs. We discovered that the injector driver circuit inside the module would intermittently drop out when it got hot. A replacement, VIN-programmed PCM like this one had their van back in reliable service the same afternoon, solving a problem that had stumped them for weeks.
Is Your Van Showing These Symptoms?
A failing PCM can cause a wide range of problems. If you’re experiencing any of the following, this module is likely the solution you need. In my 20+ years of diagnostics, these are the most common indicators I’ve seen for a faulty computer in this generation of GM trucks and vans.
- ✔ Check Engine Light is on with codes like P0601 (Internal Memory Fault) or P0606 (PCM Processor Fault).
- ✔ The engine cranks but refuses to start.
- ✔ Harsh or erratic automatic transmission shifting.
- ✔ Unexplained drop in fuel economy.
- ✔ Stalling, rough idling, or hesitation during acceleration.
- ✔ Communication errors with your scan tool.
A Straightforward Guide to Installation
Replacing the 1998-1999 Express 3500 PCM is a job most DIYers can handle with basic tools. Our pre-programming service eliminates the need for expensive dealer-only equipment, making this a simple swap.
- Safety First: Disconnect the negative terminal from your vehicle’s battery to prevent any electrical shorts.
- Locate the PCM: On the Express/Savana vans, the PCM is typically found in the engine compartment on the driver’s side, often near the battery or air filter housing.
- Disconnect the Wiring: Carefully unplug the electrical connectors from the old PCM. These connectors have locking tabs that need to be released before you can pull them off. Avoid forcing them.
- Remove the Old Module: Unbolt the PCM from its mounting bracket. Keep the hardware, as you may need it for the new unit.
- Install the New PCM: Mount your replacement module onto the bracket and securely plug in all the wiring harnesses. Ensure they click into place.
- Reconnect the Battery: Re-attach the negative battery terminal.
- Perform Security Relearn: You may need to perform a simple security relearn procedure. Turn the key to the ‘ON’ position for 10-15 minutes, then ‘OFF’ for 10 seconds. Repeat this cycle three times. On the third cycle, the vehicle should start, synchronizing the new PCM with your van’s anti-theft system.
Verified Vehicle Compatibility
This PCM is a direct fit for a wide range of GM trucks and vans from 1998 and 1999 that use service ID number 9355699. It is a guaranteed replacement for part numbers 09355699, 16266645, 16250279, 16258815, and 9366810. Please verify your part number or contact us if you are unsure. This module fits:
- ✔ 1998-1999 Chevrolet & GMC C/K 1500, 2500, 3500 Pickups (Gasoline)
- ✔ 1998-1999 Chevrolet Express & GMC Savana 1500, 2500, 3500 Vans (Gasoline)
- ✔ 1998-1999 Chevrolet Suburban & GMC 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)
This is a reliable, tested used part from a salvaged vehicle, programmed with the latest GM software updates for your specific 1998-1999 Express 3500 PCM. It’s the smart, affordable way to restore your vehicle’s performance.
Frequently Asked Questions
Why do you need my VIN?
Your Vehicle Identification Number (VIN) allows us to load the exact, correct GM factory software for your van’s specific engine, transmission, and options. This ensures the PCM works perfectly right out of the box, without a trip to the dealer.
Is this a plug-and-play part?
Yes, for the most part. Because we pre-program it to your VIN, it will control the engine and transmission correctly upon installation. However, on these GM vehicles, you will likely need to perform a simple 10-30 minute ‘security relearn’ procedure with your key so the PCM recognizes your vehicle’s anti-theft system. Instructions are included above.
What does ‘used’ mean for an electronic part?
This PCM was carefully removed from a functioning, salvaged vehicle. It is a genuine OEM part that has been inspected and tested to ensure it is fully operational. We then flash it with fresh, updated software, giving you OEM reliability at a fraction of the cost of a new unit.
Will this fix my check engine light?
If the check engine light is caused by an internal failure of your original PCM (common codes include P0601, P0602, P0606), then yes, this part will resolve the issue. It’s crucial to ensure your vehicle’s problem has been properly diagnosed as a faulty PCM before ordering.
What if I order the wrong part?
We strongly recommend matching the service ID number (e.g., 9355699) from your original module to the list provided. Providing your VIN during checkout is the best way to guarantee compatibility, as we will verify the fitment before programming and shipping.