Restore Your Van’s Reliability and Performance
If you’re dealing with a frustrating no-start condition, erratic engine behavior, or a persistent Check Engine Light on your 1998 GMC Safari, a failing Powertrain Control Module (PCM) is a very likely culprit. As a technician with over two decades of experience, I’ve seen firsthand how a faulty PCM can create a cascade of confusing problems. This isn’t just a part; it’s the central command for your vehicle’s engine and transmission, and when it fails, your workhorse van or truck is sidelined. This replacement PCM is your direct, effective solution to get back on the road with confidence.
We take the guesswork and high cost out of the equation. This is a thoroughly inspected, used OEM PCM that we program specifically for your vehicle using your VIN. This means it arrives at your door with the latest GM software updates already installed, eliminating the need for an expensive trip to the dealership for programming. It’s a straightforward fix that restores original factory performance and fuel efficiency.
A Technician’s Notebook: The Ghost in the Astro Van
I remember a 1998 Chevy Astro—the Safari’s twin—that came into my bay with a maddening intermittent crank-no-start issue. The owner had already replaced the fuel pump and ignition coil. We checked fuel pressure, spark, and sensor data, and everything looked fine—when it decided to run. After days of diagnostics, we noticed the 5-volt reference signal to the sensors would occasionally drop out. On a hunch, we connected a spare PCM. The van fired up instantly and never failed again. The original PCM had an internal failure that only appeared when it warmed up. This is a classic failure mode for these modules, and this programmed PCM is the definitive fix for those hard-to-diagnose electronic gremlins.
Is Your GM Truck or Van Showing These Signs?
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, P0605 (Internal Module Failure) or communication errors (U-codes).
- ✔ The engine cranks but will not start.
- ✔ Rough or unpredictable idling.
- ✔ Stalling for no apparent reason, either while driving or at a stop.
- ✔ A noticeable decrease in fuel economy.
- ✔ Harsh or incorrect automatic transmission shifting.
- ✔ The vehicle fails to pass an emissions test.
Your Straightforward Installation Guide
Replacing the PCM is a job most DIYers can handle with basic tools. Our pre-programming service makes it even simpler. Follow these general steps for a successful installation:
- Safety First: Always disconnect the negative terminal from your vehicle’s battery and wait at least 15 minutes for the system capacitors to discharge.
- Locate the PCM: On the 1998 GMC Safari and Chevy Astro, the PCM is typically located in the engine compartment on the driver’s side, near the battery. On other GM trucks and vans, it’s usually on the driver’s side inner fender or firewall.
- Disconnect the Harnesses: Carefully unclip and remove the electrical connectors from the old PCM. Inspect the connectors for any corrosion or damage and clean them if necessary.
- Remove the Old Module: Unbolt the old PCM from its mounting bracket. There are typically two or three bolts holding it in place.
- Install the New PCM: Mount your new, pre-programmed PCM onto the bracket and securely fasten the bolts.
- Reconnect Everything: Plug the electrical harnesses back into the new module until they click firmly into place. Reconnect the negative battery terminal.
- Perform Security Relearn: On many of these GM vehicles, you will need to perform a simple security relearn procedure to sync the new PCM with your vehicle’s anti-theft system. This usually involves turning the key to the ‘ON’ position for 10-15 minutes. Consult your vehicle’s service information for the exact procedure.
Verified Vehicle Compatibility
This module, identified by service number 09355699, is a direct replacement for part number 16258815 and other interchangeable numbers. It is guaranteed to fit the following vehicles. Please verify your part number or ID before ordering.
- ✔ 1998 GMC Safari / Chevrolet Astro (Electronic Control Module; LH front by battery, ID 9355699)
- ✔ 1998-1999 Chevrolet & GMC C/K 1500, 2500, 3500 Pickups (Gasoline, LH engine compartment, ID 9355699)
- ✔ 1998-1999 Chevrolet Suburban & GMC Yukon / Chevrolet Tahoe (Gasoline, LH engine compartment, ID 9355699)
- ✔ 1998-1999 Chevrolet Express & GMC Savana 1500, 2500, 3500 Vans (Gasoline, ID 9355699)
- ✔ 1999 Cadillac Escalade (LH front engine compartment, ID 9355699)
- ✔ 1998 Oldsmobile Bravada / GMC Envoy / Chevrolet Blazer S10 / GMC Jimmy S15 / Chevrolet S10 / GMC Sonoma (4.3L, w/o build date opt ZN4, ID 9355699)
- ✔ 1998 Isuzu Hombre (4.3L, w/o extended build date opt ZN4, ID 9355699)
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 file from GM for your vehicle’s specific engine, transmission, and options. This ensures perfect compatibility and performance right out of the box.
Is this part difficult to install?
No, this is a plug-and-play solution. The physical installation involves disconnecting the battery, swapping the module, and reconnecting everything. The only additional step is a simple security relearn procedure that requires no special tools.
Is this a new part?
No, this is a high-quality, tested used OEM part sourced from a salvaged vehicle. We inspect every unit for integrity and then flash it with the latest software, providing a reliable and cost-effective alternative to a new dealership part.
Will I need to do anything else after installation?
In most cases, you will need to perform a ‘Passlock’ or ‘VATS’ security relearn procedure. This is a simple process that typically involves turning the ignition on for 10 minutes, off for 10 seconds, and repeating two more times. This syncs the new PCM to your vehicle’s anti-theft system.
What if my part number is slightly different?
This PCM, identified by service number 09355699, is interchangeable with several part numbers including 16258815, 16266645, 16250279, and 09366810. As long as your vehicle is on our compatibility list and your original module has one of these numbers, this part will work perfectly once programmed to your VIN.