Get Your Van Back on the Road with a Reliable, Programmed PCM
Is your Chevrolet Express or GMC Savana van giving you headaches? If you’re dealing with frustrating issues like a no-start condition, intermittent stalling, erratic shifting, or a persistent Check Engine Light, a failing Powertrain Control Module (PCM) is often the culprit. As the central computer for your engine and transmission, its health is critical to your vehicle’s performance and reliability. This isn’t just a part; it’s the solution to getting your dependable workhorse running right again.
This is a thoroughly tested, used OEM engine computer, part number 9355699, sourced from a salvaged vehicle. The real value we provide is in the service: before this module ships, we flash it with the latest official GM software updates and program it specifically to your vehicle’s Vehicle Identification Number (VIN). This means it arrives ready for installation, eliminating the need for an expensive trip to the dealership for programming. You get a cost-effective, direct-fit solution that restores factory performance.
A Technician’s Notebook: The Ghost in the Machine
I once had a 1999 Savana 2500 in my bay that was driving the owner crazy. It would run perfectly for days, then suddenly refuse to start, only to fire right up an hour later. No consistent codes, just random communication errors. We checked grounds, wiring, and sensors for two days. On a hunch, I tapped the PCM casing with a screwdriver handle while the engine was idling, and it instantly stalled. The culprit was a hairline crack on the internal circuit board, causing intermittent failures. A replacement, programmed PCM like this one had the van running reliably in under 30 minutes. Sometimes, the most complex problems have the simplest solutions.
Is Your GM Truck or Van Showing These Signs?
A failing PCM can manifest in numerous ways. If you’re experiencing any of the following, this module is the likely fix you need. In my 20+ years of experience, these are the most common indicators I’ve seen in the shop:
- ✔ Unexplained Check Engine Light with codes like P0601 (Internal Control Module Memory Check Sum Error) or P0605 (Internal Control Module ROM Error).
- ✔ The engine cranks but refuses to start.
- ✔ Sudden stalling or rough idling for no apparent reason.
- ✔ Noticeably poor fuel economy.
- ✔ Harsh or erratic automatic transmission shifting.
- ✔ Failure to communicate with a diagnostic scan tool.
- ✔ Failed emissions testing due to module-related faults.
A Straightforward Guide to Installation
Installing your pre-programmed 1998-1999 Express 1500 PCM is a manageable job for a DIYer with basic tools. Following these steps ensures a smooth process:
- Safety First: Always disconnect the negative terminal from your vehicle’s battery and secure it away from the post to prevent any accidental power surges.
- Locate the Old PCM: On most Express and Savana vans, the PCM is located in the engine compartment on the driver’s side, often near the battery or firewall. It’s a silver metal box with multiple large wiring harness connectors.
- Disconnect the Harnesses: Carefully release the locking tabs on each electrical connector and pull them straight out from the module. Avoid pulling on the wires themselves. Some connectors have levers or bolts that need to be loosened first.
- Remove the Module: Unbolt the old PCM from its mounting bracket. Keep the hardware, as you’ll need it to install the new unit.
- Install the New PCM: Mount your new, pre-programmed PCM onto the bracket and secure it with the original hardware.
- Reconnect Everything: Firmly plug the wiring harnesses back into the correct ports on the new module. You will hear a click when they are properly seated. Reconnect your vehicle’s negative battery terminal.
- Perform Security Relearn (If Necessary): Some GM vehicles of this era require a simple security relearn procedure to sync the new PCM with the anti-theft system. This usually involves turning the key to the ‘ON’ position for 10-15 minutes. Consult your owner’s manual or a reliable online resource for your specific model’s procedure.
Verified Vehicle Compatibility
This module, identified by service number 9355699, is a direct replacement for a wide range of GM trucks and vans. Please verify your original part number or match your vehicle from the list below. This part is interchangeable with numbers: 16266645, 16250279, 16258815, 09366810, and 9366810.
GMC 1500/2500/3500 PICKUP (1998-1999)
CHEVROLET EXPRESS 1500/2500/3500 VAN (1998-1999)
GMC SAVANA 1500/2500/3500 VAN (1998-1999)
CHEVROLET TAHOE (1998-1999)
GMC YUKON (1998-1999)
CADILLAC ESCALADE (1999)
CHEVROLET SUBURBAN 1500/2500 (1998-1999)
CHEVROLET ASTRO (1998)
GMC SAFARI (1998)
CHEVROLET S10 / GMC SONOMA (1998)
CHEVROLET BLAZER / GMC JIMMY (1998)
OLDSMOBILE BRAVADA (1998)
GMC ENVOY (1998)
ISUZU HOMBRE (1998)
Note: Please ensure your original module has ID 9355699 for guaranteed compatibility.
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 calibration and updates from GM for your specific engine, transmission, and options. This ensures perfect compatibility and performance right out of the box.
Is this a new part?
No, this is a genuine, used OEM part that has been carefully sourced from a salvaged vehicle. We test each unit to ensure it’s fully functional before programming and shipping it to you. This provides an affordable and reliable alternative to finding a new part for an older vehicle.
Will I need to do anything else after installation?
In most cases, the installation is plug-and-play. However, some GM vehicles may require a simple, key-on security relearn procedure that takes about 10-15 minutes to complete. This does not require any special tools. We recommend checking the specific procedure for your model.
What happens after I place my order?
After you complete your purchase, you will need to send us your 17-digit VIN. You can typically add it as a note during checkout or send it in a message to us. We cannot program or ship your module until we receive your VIN. Once programmed, we will ship it out promptly.
Will this fix my transmission shifting problems?
Yes, in many cases it will. The PCM controls both engine functions and automatic transmission shift points and pressures. If the module is failing, it can cause hard shifts, delayed shifting, or hunting for gears. Replacing a faulty PCM often resolves these electronic transmission issues.