If you’re dealing with a frustrating no-start condition, a persistent check engine light, or erratic engine behavior in your 1998-1999 Chevrolet Astro or other compatible GM vehicle, a failing Powertrain Control Module (PCM) is often the culprit. As the central computer for your engine and transmission, its health is critical for performance, fuel economy, and reliability. I’ve spent two decades diagnosing these exact issues, and I can tell you that swapping a faulty PCM doesn’t have to mean an expensive trip to the dealership.
This is a direct-fit replacement Powertrain Control Module, service number 16250279. The best part? We handle the complicated part for you. Before we ship it, we flash the module with the latest official GM software updates, programmed specifically to your vehicle’s VIN. This means no special scan tools or programming procedures are needed on your end. It arrives ready to install, saving you time, money, and headaches.
A Technician’s Notebook: The Ghost in the Astro Van
I remember a 1999 Astro van that came into the shop with a problem that was driving the owner crazy. It would stall intermittently at stoplights, but never consistently enough to catch it in the act. No clear trouble codes were stored, just a history of random misfires. We checked fuel pressure, ignition components, and sensors—all were fine. After hours of diagnostics, we decided to monitor the PCM data stream on a long test drive. Sure enough, we saw the processor data drop out for a split second right before it would stall. It was a classic case of an internal PCM failure caused by heat and age. A pre-programmed module like this one had the van running reliably in under an hour.
Is Your GM Vehicle Showing These Signs?
A failing PCM can manifest in many ways. If you’re noticing any of the following, it might be time for a replacement:
- ✔ Check Engine Light is on with codes like P0601 (Internal Memory Fault) or P0606 (PCM Processor Fault)
- ✔ The engine cranks but refuses to start
- ✔ Rough or unstable idling
- ✔ A noticeable drop in fuel efficiency
- ✔ Harsh or incorrect automatic transmission shifting
- ✔ Intermittent stalling or hesitation during acceleration
- ✔ Communication errors with your scan tool
A Straightforward Guide to Installation
Replacing the PCM on these GM vehicles is a job most DIYers can handle. Here’s a basic guide to get you started:
- Safety First: Disconnect the negative terminal from your vehicle’s battery and secure it away from the post.
- Locate the PCM: On a Chevy Astro or GMC Safari, the PCM is typically located in the engine compartment on the driver’s side, near the battery. On other GM trucks and SUVs, it’s usually on the driver’s side fender or firewall.
- Disconnect the Harnesses: Carefully unclip and remove the electrical connectors from the old module. These connectors have locking tabs that need to be released before pulling.
- Remove the Old Module: Unbolt the PCM from its mounting bracket and remove it from the vehicle.
- Install the New Module: Mount your new, pre-programmed PCM into the bracket and securely reconnect all electrical harnesses. Ensure they click into place.
- Reconnect the Battery: Reattach the negative battery terminal.
- Perform Security Relearn (If Needed): In some cases, you may need to perform a simple security relearn procedure. Turn the key to the ‘ON’ position for 10-15 minutes, then turn it off for 10 seconds. Repeat this cycle 2-3 times. This allows the vehicle’s security system to recognize the new PCM.
Verified Fitment for Your GM Truck, Van, or SUV
This module is a direct replacement for service number 16250279 and is also compatible with part numbers 09366810 and 09355699. Please verify your original part number before ordering. This part fits a wide range of vehicles, including:
- Chevrolet: Astro Van (98-99), Blazer S10 (98), C/K Pickups 1500/2500/3500 (98-99), Express Van 1500/2500/3500 (98), S10 Pickup (98), Suburban (98-99), Tahoe (98-99)
- GMC: C/K Pickups 1500/2500/3500 (98-99), Envoy (98), Jimmy S15 (98), Safari Van (98-99), Savana Van 1500/2500/3500 (98), Sonoma (98), Yukon (98-99)
- Cadillac: Escalade (99)
- Oldsmobile: Bravada (98)
- Isuzu: Hombre (98)
Note: Specific engine and option compatibility is critical. This list is for general guidance. The programming we provide is based on the VIN you supply.