Is Your GM Truck or Van Running Rough?
If you’re dealing with a persistent check engine light, erratic engine behavior, a no-start condition, or failing emissions tests in your 1998 GM vehicle, a failing Powertrain Control Module (PCM) is often the culprit. As the central computer, the PCM manages everything from fuel injection and spark timing to transmission shifting. When it fails, it can cause a cascade of frustrating and hard-to-diagnose issues. This isn’t just an inconvenience; it’s a problem that affects your vehicle’s reliability and safety.
The Direct-Fit Solution: A VIN-Programmed PCM
Get your truck back to factory-spec performance with this dependable, used OEM engine computer. We take the guesswork and high cost out of the repair. Before this module ships, our experienced technicians will program it with the latest GM-certified software using the specific Vehicle Identification Number (VIN) from your truck. This ensures it’s a true plug-and-play solution, ready for installation right out of the box—no expensive trip to the dealership for programming is required.
Expert Pro Tip: Check Your Connections First!
Before you condemn your old PCM, take a moment to inspect the main harness connectors. On these late-90s GM trucks, I’ve seen countless cases where a green, corroded pin or a loose ground wire caused the exact same symptoms as a failed computer. Disconnect the battery, unplug the PCM, and use a small brush and electrical contact cleaner on both the harness-side and module-side pins. A few minutes of cleaning can sometimes save you the cost of a replacement part. If the pins are clean and tight, you can be confident the module itself is the issue.
Common Symptoms of a Failing 1998 S10 Sonoma PCM
A faulty engine computer can manifest in numerous ways. If you’re experiencing any of the following, this module is your solution:
- ✔ Check Engine Light (CEL) is on with communication codes (like P0601, P0605) or multiple unrelated sensor codes.
- ✔ Engine cranks but will not start.
- ✔ Poor fuel economy and engine performance.
- ✔ Harsh or erratic automatic transmission shifting.
- ✔ Intermittent stalling or stumbling while driving.
- ✔ Failure to pass state emissions testing.
Simple, DIY-Friendly Installation
You don’t need to be a master technician to replace this module. With basic hand tools, you can get your vehicle running properly in under an hour.
- Safety First: Disconnect the negative battery terminal and wait 10 minutes for the system to discharge.
- Locate the PCM: On most S10/S15/Sonoma models, the PCM is located in the engine bay, often on the driver’s or passenger’s side fender well or firewall.
- Disconnect Connectors: Carefully release the locking tabs and unplug the wiring harnesses from the old module.
- Swap the Modules: Unbolt the old PCM and secure the new, pre-programmed module in its place.
- Reconnect Everything: Plug the wiring harnesses firmly into the new PCM until they click. Reconnect the negative battery terminal.
- Final Step: Your vehicle may require a security relearn procedure, which can typically be done by cycling the key. Your specific instructions will be included with the part.
Guaranteed Compatibility
This module is a direct replacement for service number 09355699 and is also interchangeable with part numbers 16266645, 9355699, 16250279, 16258815, 09366810, and 9366810. It fits a wide range of 1998-1999 GM trucks and vans, including the Chevrolet S10, GMC Sonoma, Blazer, Jimmy, Astro, Safari, and full-size trucks and vans. Please verify your original part number to ensure a perfect match.