Is Your GM Truck or Van Running Rough?
If your 1998-1999 GM vehicle is suffering from a no-start condition, erratic shifting, a persistent check engine light, or poor fuel economy, a failing Powertrain Control Module (PCM) is a very common culprit. Over two decades of experience in the shop has shown me that heat, vibration, and age take their toll on these critical components, leading to frustrating and hard-to-diagnose issues. You’re not just buying a part; you’re buying a solution to get your reliable truck back on the road.
This is a genuine, used OEM Engine Computer, part number 9355699, sourced from a salvaged vehicle and rigorously tested. Before we ship it, we flash it with the latest official GM software calibration specific to your vehicle’s VIN. This ensures perfect compatibility and restores performance, often fixing issues the original software never addressed.
The Right Fix for Your 1998 S10 PCM
A customer’s 1998 S10 came in last week with these exact symptoms: it would crank but not start, and when it did run, it felt sluggish and threw random misfire codes. We checked for spark and fuel pressure, which were fine. The issue was intermittent injector pulse, a classic sign of a failing driver inside the PCM. Swapping in one of our VIN-programmed modules had it running smoothly in under 30 minutes. This is the fix you need for those confusing electronic gremlins.
Key Benefits of This Engine Computer:
- โ VIN-Programmed for You: We handle the programming. No expensive trips to the dealer for flashing. Just provide your VIN at checkout, and it arrives ready to install.
- โ Restores Original Performance: Loaded with the newest GM software updates to correct factory drivability issues and optimize engine and transmission function.
- โ Cost-Effective Solution: Get a reliable, tested OEM part for a fraction of the cost of a new module from a dealership.
- โ Broad Compatibility: This single module replaces a wide range of part numbers and fits dozens of GM trucks and vans from 1998-1999.
Expert Pro Tip: Before installing your replacement PCM, take five minutes to clean the main engine-to-chassis ground straps. On these older GM trucks, a corroded or loose ground can cause voltage issues that mimic PCM failure. A quick cleaning with a wire brush can prevent misdiagnosis and protect your new module.
Plug-and-Play Installation: No Dealer Visit Required
You can do this job yourself with basic hand tools. Hereโs a general guide for a 1998 S10 PCM replacement:
- Safety First: Disconnect the negative terminal from your vehicle’s battery.
- Locate the PCM: On most S10/S15 models, the PCM is located in the engine bay, often near the battery or on the passenger-side fender well. Full-size trucks and vans may have it on the LH inner fender.
- Disconnect Harnesses: Carefully unclip and remove the electrical connectors. Inspect the pins for any corrosion or damage.
- Swap the Module: Unbolt the old PCM and secure the new, programmed module in its place.
- Reconnect and Test: Re-attach the electrical harnesses, ensuring they click securely into place. Reconnect the battery terminal. The vehicle may require a security relearn procedure, which typically involves turning the key to the ‘ON’ position for 10-15 minutes.
Guaranteed Fitment Confirmation
To ensure this is the correct part, please match your existing module’s service number to 9355699. This unit is a direct replacement for the following part numbers:
09355699, 16266645, 16250279, 16258815, 09366810, 9366810
This PCM fits a wide variety of 1998 and 1999 Chevrolet, GMC, Cadillac, and Isuzu models, including the S10/Sonoma, Blazer/Jimmy, Tahoe/Yukon, Suburban, C/K Pickups, Express/Savana Vans, and more. Please refer to the detailed fitment list to confirm your specific vehicle and options.