Get Your Workhorse Van Running Right Again
Is your 1998 or 1999 GMC Savana 3500 van giving you headaches? If you’re dealing with frustrating issues like intermittent stalling, a persistent check engine light, harsh transmission shifting, or even a no-start condition, a failing Powertrain Control Module (PCM) is often the culprit. As the brain of your vehicle’s engine and transmission, when the PCM starts to fail, it can cause a wide range of confusing and debilitating problems. This isn’t just an inconvenience; for a work van, it means downtime and lost money.
This is a reliable, tested, and used OEM engine computer that offers a dependable and cost-effective solution. The best part? We handle the most critical step for you. Before we ship it, our technicians will program the module with the latest GM software updates, specifically flashed to your vehicle’s unique VIN. This means it arrives ready for installation, saving you a costly trip to the dealership and the high price of a new unit. Simply provide your VIN at checkout, and we’ll take care of the rest.
A Technician’s Notebook: The Phantom Stall
I once had a 1999 Chevy Express 3500 (the Savana’s twin) in my bay that was driving the owner crazy. It would run perfectly for days, then suddenly stall at a stoplight and refuse to restart for 10-15 minutes. There were no consistent codes, just a random P0601 (Internal Control Module Memory Check Sum Error) that would appear and disappear. After checking all the usual suspects—fuel pressure, ignition system, grounds—we finally focused on the PCM. On these vans, heat soak from the engine compartment can bake the internal components of the computer over 20+ years, causing these exact intermittent failures. Swapping in a correctly programmed PCM fixed it instantly. It’s a classic failure mode I’ve seen dozens of times on these GMT600 platform vehicles.
Is Your Van Showing These Symptoms?
A failing PCM can manifest in many ways. If you’re experiencing any of the following, this module is likely the solution you need:
- ✔ Check Engine Light is on with codes like P0601, P0602, or P0606
- ✔ Engine stalls for no reason or is difficult to start
- ✔ Noticeable decrease in fuel economy
- ✔ Transmission shifts erratically, harshly, or gets stuck in one gear
- ✔ Vehicle is in “limp mode” with reduced power
- ✔ Communication errors with your scan tool
A Straightforward Guide to Installation
Replacing the PCM in your Savana or Express van is a job most DIYers can handle with basic tools. The module is typically located in the engine compartment on the driver’s side.
- Safety First: Always disconnect the negative terminal from your vehicle’s battery before starting any electrical work.
- Locate the PCM: Find the module in the engine bay. It will have several large wiring harness connectors attached to it.
- Disconnect the Harnesses: Carefully release the locking tabs and unplug all electrical connectors from the old PCM. Avoid forcing them.
- Remove the Old Module: Unbolt the old PCM from its mounting bracket and remove it from the vehicle.
- Install the New Module: Bolt your new, pre-programmed PCM into the mounting bracket.
- Reconnect Everything: Firmly plug the wiring harnesses back into the new PCM, ensuring the locking tabs click into place. Reconnect the negative battery terminal.
- Security Relearn: On many of these GM vehicles, you may need to perform a simple security relearn procedure. This typically involves turning the key to the ‘ON’ position for 10-15 minutes, then off, and repeating two more times. This allows the new PCM to sync with your vehicle’s anti-theft system.
Verified Vehicle Compatibility
This module, identified by service numbers like 9366810, 09355699, and 16266645, is a direct replacement for a wide range of GM trucks and vans. Please verify your part number or match your vehicle from the list below. This unit fits models where the ECM is identified as ID 9355699.
- Cadillac Escalade: 1999
- Chevrolet Astro / GMC Safari: 1998
- Chevrolet Blazer / GMC Jimmy S15: 1998
- Chevrolet & GMC C/K 1500, 2500, 3500 Pickups: 1998-1999 (Gasoline Engines)
- Chevrolet Express & GMC Savana 1500, 2500, 3500 Vans: 1998-1999 (Gasoline Engines)
- Chevrolet S10 / GMC Sonoma: 1998 (4.3L V6)
- Chevrolet Suburban 1500 & 2500: 1998-1999 (Gasoline Engines)
- Chevrolet Tahoe & GMC Yukon: 1998-1999 (Gasoline Engines)
- Isuzu Hombre: 1998 (4.3L V6)
- Oldsmobile Bravada: 1998
- GMC Envoy: 1998
This is the definitive solution for your 1998-1999 Savana 3500 PCM failure. Don’t let a faulty computer keep your van off the road. Order today and get back to work with confidence.
Frequently Asked Questions
Why do you need my VIN?
Your Vehicle Identification Number (VIN) is essential. It allows us to program the PCM with the exact software and calibrations for your van’s specific engine, transmission, and options. This ensures perfect compatibility and function, just like a part from the dealer.
Is a used PCM reliable?
Absolutely. We source genuine OEM modules from salvaged vehicles and thoroughly test them to ensure they are fully functional. An OEM part is often more reliable than a new aftermarket alternative, and this one comes with the latest software updates for improved performance.
Do I need any special tools to install this?
Basic hand tools (like a socket set) are all you need for the physical installation. Because we pre-program the module, you won’t need a dealership scan tool for flashing. You may need to perform a simple key-cycle security relearn, which requires no tools.
What is a security relearn procedure?
It’s a simple process that syncs the new PCM to your vehicle’s anti-theft system (Passlock/VATS). Without it, the vehicle may not start. It typically involves turning the key to ‘ON’ for 10 minutes, OFF for 10 seconds, and repeating this sequence three times. Instructions are readily available online for your specific model.
Will this fix my transmission shifting problems?
In many cases, yes. The PCM also controls transmission functions, including shift points and line pressure. If your transmission issues are electronic and caused by a failing computer, this programmed 1998-1999 Savana 3500 PCM will resolve them. However, it will not fix internal mechanical failures in the transmission itself.