Get Your Workhorse Van Back on the Road Fast
As a mechanic with over two decades of experience, I know that when your 1998-1999 Chevy Express Van starts acting up, it’s more than an inconvenience—it’s costing you time and money. Intermittent stalling at stoplights, a check engine light that won’t go away, or a complete no-start condition can often be traced back to a single, vital component: the Powertrain Control Module (PCM). This isn’t just another part; it’s the brain of your vehicle’s engine and transmission, and when it fails, it can create a cascade of frustrating, hard-to-diagnose problems.
This is a reliable, tested PCM, part number 16258815, sourced from a salvaged vehicle. The real value here isn’t just the hardware; it’s the service. We professionally flash this computer with the latest official GM software updates, specifically programmed to your van’s unique Vehicle Identification Number (VIN). This means you get a part that is truly plug-and-play, eliminating the need for an expensive trip to the dealership for programming. It’s the most efficient and cost-effective way to solve complex electronic issues and restore your van’s performance and reliability.
Case Study: A Tricky Diagnosis
I once had a local contractor bring in his ’99 Express 2500. The van would run fine for days, then suddenly stall in traffic and refuse to restart for an hour. He’d already replaced the fuel pump and crank sensor, but the problem persisted. No consistent trouble codes were stored, just a few random communication errors. After checking the wiring harness for the third time, we hooked up a scope to the PCM outputs. We found the 5-volt reference signal would intermittently drop out, causing the whole system to crash. A replacement, programmed PCM like this one had him back on the job site the next day, problem-free. These symptoms are classic signs of internal PCM failure.
Is Your Van or Truck Showing These Signs?
A failing PCM can manifest in many ways. If you’re experiencing any of the following, this module is very likely the solution you need:
- ✔ Unexplained Check Engine Light (CEL) illumination, especially for codes like P0601 (Internal Control Module Memory Check Sum Error).
- ✔ Engine stalling, stumbling, or running rough for no apparent reason.
- ✔ Complete no-start condition where the engine cranks but will not fire up.
- ✔ Harsh or erratic automatic transmission shifting.
- ✔ Poor fuel economy that has gotten noticeably worse over time.
- ✔ Communication errors with diagnostic scan tools.
A Straightforward Guide to Swapping Your PCM
Installing your new 1998-1999 Express 1500 PCM is a job most DIYers can handle in under 30 minutes with basic hand tools. The key is our pre-programming service, which handles the complicated part for you.
- Safety First: Always disconnect the negative terminal from your vehicle’s battery before working on any electronic components.
- 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 firewall. It’s a silver metal box with several large wiring harness connectors.
- Disconnect the Harnesses: Carefully unclip and remove all electrical connectors from the old PCM. They have locking tabs that need to be released. Avoid pulling on the wires themselves.
- Remove the Old Module: Unbolt the PCM from its mounting bracket. There are typically a few 10mm bolts holding it in place.
- Install the New Module: Bolt your new, pre-programmed PCM into the mounting bracket. Reconnect all wiring harnesses, ensuring they click securely into place.
- Reconnect the Battery: Reattach 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 2-3 times. This allows the vehicle’s anti-theft system to recognize the new PCM. The vehicle should now start and run correctly.
Verified Vehicle Compatibility
This PCM, identified by service number 16258815 or ID 9355699, is a direct replacement for a wide range of GM trucks and vans. Please verify your part number or consult the list below. This unit is compatible with the following models:
- Astro / Safari (GMC): 1998
- Blazer S10 / Jimmy S15: 1998 (w/o build date opt ZN4)
- Bravada: 1998 (w/o build date opt ZN4)
- Cadillac Escalade: 1999
- Chevrolet / GMC Pickup (1500/2500/3500): 1998-1999 (Gasoline)
- Envoy: 1998 (w/o build date opt ZN4)
- Express / Savana Van (1500/2500/3500): 1998-1999 (Gasoline)
- Isuzu Hombre: 1998 (4.3L, w/o extended build date opt ZN4)
- S10 / S15 / Sonoma: 1998 (4.3L, w/o build date opt ZN4)
- Suburban (1500/2500): 1998-1999 (Gasoline)
- Tahoe / Yukon: 1998-1999 (Gasoline)
After purchase, please provide your VIN so we can ensure perfect programming before shipment.
Frequently Asked Questions
Do I need to do any programming myself?
No. We handle all the programming before we ship the part. We flash it with the latest GM software and calibrate it to your specific VIN, making it ready for installation right out of the box.
Is this a new part?
This is a high-quality, tested computer sourced from a salvaged vehicle. Each unit is inspected and verified to be fully functional before being programmed and shipped. This provides a reliable, cost-effective solution.
What is the ‘Security Relearn’ and is it difficult?
The security relearn (or anti-theft relearn) is a simple procedure that syncs the new PCM to your vehicle’s security system. It typically involves cycling the ignition key and waiting, requiring no special tools. We include simple instructions.
Will this fix my specific problem?
This 1998-1999 Express 1500 PCM is the direct solution for issues caused by a failing computer, such as internal circuit faults, communication errors, and driver failures. While it can’t fix a bad sensor or wiring, it resolves the core electronic brain of the system.
How do I provide my VIN?
After you complete your purchase, simply send us a message with your 17-digit Vehicle Identification Number (VIN). We cannot program and ship your module without it.