Restore Your Truck’s Brain and Get Back on the Road
Is your 1998 Chevrolet S10 or GMC Sonoma suddenly giving you fits? Unexplained stalling, a persistent check engine light, or a complete no-start condition can be incredibly frustrating. In my 20+ years of turning wrenches and diagnosing complex automotive electronics, I’ve seen these symptoms countless times. Often, the culprit isn’t a bad sensor or wiring—it’s the Powertrain Control Module (PCM), the central computer that manages everything from fuel delivery to spark timing. When it fails, your reliable truck can become a driveway ornament. This listing is for a dependable, tested, used OEM engine computer that solves that problem directly.
What makes this offer different is our professional programming service. We don’t just ship you a random part. You provide us with your vehicle’s VIN, and we flash this PCM with the latest GM software updates specific to your truck. This ensures that it communicates perfectly with your engine, transmission, and all other onboard systems, just like a new part from the dealership, but at a fraction of the cost. This is the smart, efficient solution for both seasoned mechanics and DIY warriors looking to get the job done right the first time.
A Technician’s Notebook: The Intermittent Stall on a 4.3L
I once had a ’98 GMC Jimmy with the 4.3L V6 come into my bay with an issue that had stumped two other shops. The owner said it would run fine for days, then suddenly die at a stoplight and refuse to restart for an hour. There were no consistent trouble codes, just a history of random communication errors. After checking all the usual suspects—fuel pressure, crank sensor, ignition module—everything tested fine. On a hunch, I monitored the 5-volt reference signal from the PCM while tapping on the computer housing. Sure enough, the voltage would flicker and drop, causing the engine to stumble. The internal board had developed a micro-fracture that only acted up when it got hot. Swapping in a properly programmed PCM like this one solved the issue permanently. It’s a classic example of how a failing computer can create ghost-like problems that are impossible to trace without experience.
Is Your Truck Showing These Symptoms?
A faulty engine computer can manifest in numerous ways. If you’re experiencing any of the following, a failing PCM could be the root cause:
- ✔ Check Engine Light is on with communication-related codes (like P0601, P0605) or multiple unrelated sensor codes.
- ✔ The engine cranks but refuses to start.
- ✔ Rough or erratic idling and stalling for no apparent reason.
- ✔ A noticeable decrease in fuel economy.
- ✔ The transmission shifts harshly or at the wrong times.
- ✔ Your scan tool cannot communicate with the PCM.
A Straightforward Guide to Installation
Replacing your 1998 S10 PCM is a manageable job for most DIYers. With our pre-programming, you eliminate the most complicated step. Follow this general guide for a smooth installation:
- Safety First: Disconnect the negative terminal from your vehicle’s battery to prevent any electrical shorts.
- Locate the PCM: On most of these GM trucks and vans, the PCM is located in the engine compartment, often on the driver’s or passenger’s side fender well or near the battery. It’s a silver metal box with multiple large wiring harness connectors.
- Disconnect the Harnesses: Carefully release the locking tabs on the electrical connectors and pull them straight out from the PCM. Avoid pulling on the wires themselves.
- Remove the Old Module: Unbolt the PCM from its mounting bracket. Keep the hardware as you will need it to install the new unit.
- Install the New PCM: Mount your VIN-programmed PCM onto the bracket and securely tighten the bolts.
- Reconnect Everything: Plug the wiring harnesses back into the new module until they click into place. Reconnect your battery’s negative terminal.
- Perform Security Relearn (If Necessary): On many of these vehicles, you will need to perform a simple security relearn procedure. This usually involves turning the key to the ‘ON’ position for 10-15 minutes, then off, and repeating two more times. This allows the new PCM to sync with your vehicle’s anti-theft system. Your truck will not start until this is completed.
Verified Vehicle Compatibility
This module, identified by part number 09366810, is a direct replacement for service numbers 09355699, 16266645, 16250279, and 16258815. It fits a wide range of 1998 and 1999 GM trucks and vans. Please verify your part number or consult the list below. This is a partial list based on the common ID 9355699:
- ✔ 1998 Chevrolet S10 / GMC Sonoma (4.3L V6)
- ✔ 1998 Chevrolet Blazer / GMC Jimmy / Oldsmobile Bravada (4.3L V6)
- ✔ 1998 Isuzu Hombre (4.3L V6)
- ✔ 1998-1999 Chevrolet & GMC C/K 1500, 2500, 3500 Pickups (Gasoline Engines)
- ✔ 1998-1999 Chevrolet Tahoe & GMC Yukon (Gasoline Engines)
- ✔ 1999 Cadillac Escalade
- ✔ 1998-1999 Chevrolet Suburban 1500 & 2500 (Gasoline Engines)
- ✔ 1998-1999 Chevrolet Express & GMC Savana 1500, 2500, 3500 Vans (Gasoline Engines)
- ✔ 1998 Chevrolet Astro & GMC Safari
This reliable, programmed 1998 S10 PCM is your path to a smooth-running truck. Don’t let a faulty computer keep you sidelined. Order today and let us handle the programming for you.
Do I need to do anything after installing this PCM?
Do I need to do anything after installing this PCM?
Yes. While we program the unit to your VIN, you will likely need to perform a security relearn procedure, also known as a Passlock or VATS relearn. This is a simple process that typically takes about 30 minutes and involves cycling the ignition key. Instructions are widely available online for your specific model, and it requires no special tools.
What information do you need from me?
After you complete your purchase, you must provide us with your vehicle’s 17-digit Vehicle Identification Number (VIN). We cannot ship the module until we have this information, as it is required to load the correct GM software for your truck’s specific configuration.
Is this a new part?
No, this is a high-quality, tested used OEM part that has been sourced from a salvaged vehicle. We inspect and verify each unit to ensure it is fully functional before programming and shipping. This provides a reliable and affordable alternative to a costly new module.
Will this fix my check engine light?
If your check engine light is caused by an internal failure of the PCM itself (e.g., DTC P0601), then yes, this part will resolve the issue. However, if the light is on due to a faulty sensor, bad wiring, or another mechanical problem, you will still need to diagnose and repair that separate issue. This PCM will restore correct computer operation, allowing for accurate diagnosis of other potential problems.