Is Your 1998 GM Truck or Van Acting Up? Let’s Get It Fixed.
As a technician with over two decades of experience under the hood, I’ve seen my share of frustrating electrical gremlins. If your 1998 Chevrolet S10, GMC Sonoma, or another GM vehicle from that era is suddenly stalling, shifting erratically, or refusing to start, the Powertrain Control Module (PCM) is a prime suspect. This isn’t just a part; it’s the brain of your engine, and when it fails, it can cause a cascade of confusing problems. This isn’t the time for guesswork. You need a reliable, straightforward solution to get your vehicle back to its dependable self.
This is a tested, genuine GM Powertrain Control Module, part number 16266645. The biggest advantage we offer is that we flash it with the latest GM software updates specifically for your vehicle’s VIN before it ships. This means you get a component that is ready to install right out of the box, eliminating the need for an expensive trip to the dealership for programming. We take a quality used part and make it a plug-and-play fix for your truck or van.
Case Study: The Intermittent S10 Stall
A customer brought in his ’98 S10 with the 4.3L V6. The truck would run perfectly for days, then suddenly die at a stoplight and refuse to restart for 20 minutes. There were no consistent trouble codes, just a history of random misfires. We checked fuel pressure, spark, and sensors—all were fine. On a hunch, I tapped the PCM with a screwdriver handle while the engine was running, and it immediately stalled. The culprit was an internal solder joint failure inside the module, a common issue on these older units. Replacing the PCM with a properly programmed unit like this one solved the problem permanently.
Common Signs of a Failing PCM
A faulty engine computer can manifest in many ways. If you’re experiencing any of the following, it might be time to replace your 1998 S10 Sonoma PCM:
- ✔ Check Engine Light is on with codes like P0601 (Internal Memory Error) or P0606 (PCM Processor Fault).
- ✔ The engine cranks but refuses to start.
- ✔ Unexplained stalling or rough idling.
- ✔ A noticeable drop in fuel economy.
- ✔ The transmission isn’t shifting correctly or feels like it’s slipping.
- ✔ Failure to pass an emissions test.
A Straightforward Guide to Installation
Installing your new PCM is a job most DIYers can handle in under 30 minutes with basic hand tools. This pre-programmed module for your 1998 S10 Sonoma PCM makes the process much simpler.
- Safety First: Disconnect the negative terminal from your vehicle’s battery to prevent any electrical shorts.
- Locate the PCM: On most of these 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.
- Disconnect the Connectors: Carefully unclip the wiring harness connectors from the old module. There are typically release tabs that need to be pressed or lifted. Avoid pulling on the wires themselves.
- Remove the Old Module: Unbolt the old PCM from its mounting bracket and remove it from the vehicle.
- Install the New Module: Bolt your new, pre-programmed PCM into the mounting bracket.
- Reconnect Everything: Firmly plug the wiring harnesses into the new module until they click into place. Reconnect the negative battery terminal.
- Perform Security Relearn: Your vehicle may require a simple security relearn procedure to recognize the new PCM. This typically involves turning the key to the ‘ON’ position for 10-15 minutes. Consult your owner’s manual for the specific procedure for your model.
Verified Vehicle Compatibility
This module, identified by service number 16266645 or ID 09355699, is a direct replacement for a wide range of GM trucks and vans. Please verify your original part number matches one of the following for guaranteed compatibility: 09355699, 16266645, 9355699, 16250279, 16258815, 09366810, 9366810. This part fits many models, including:
- ✔ 1998-1999 Chevrolet & GMC C/K 1500, 2500, 3500 Pickups (Gasoline)
- ✔ 1998-1999 Chevrolet Tahoe & GMC Yukon (Gasoline)
- ✔ 1998-1999 Chevrolet & GMC Suburban (Gasoline)
- ✔ 1998-1999 Chevrolet Express & GMC Savana 1500, 2500, 3500 Vans (Gasoline)
- ✔ 1999 Cadillac Escalade
- ✔ 1998 Chevrolet S10 / GMC Sonoma (4.3L V6)
- ✔ 1998 Chevrolet Blazer / GMC Jimmy / Oldsmobile Bravada (4.3L V6)
- ✔ 1998 Chevrolet Astro / GMC Safari
- ✔ 1998 Isuzu Hombre (4.3L V6)
Restoring the performance and reliability of your vehicle is our top priority. By providing your VIN at checkout, you ensure this 1998 S10 Sonoma PCM arrives ready for a hassle-free installation.
Frequently Asked Questions
How do I provide my VIN?
After you complete your purchase, simply send us a message with your 17-digit Vehicle Identification Number (VIN). We cannot program and ship the module without it.
Is this a new part?
No, this is a high-quality, tested used OEM part sourced from a salvaged vehicle. We inspect and program it to ensure full functionality.
Do I need to do anything after installation?
In most cases, you will need to perform a security relearn procedure, also known as a VATS relearn. This is a simple process that typically takes about 30 minutes and involves cycling the ignition key. We can provide instructions if needed.
Will this fix my specific problem?
This module will correct issues directly caused by a faulty PCM. While the symptoms listed are common, it’s crucial to have your vehicle properly diagnosed. This part will not fix problems related to other bad sensors or mechanical failures.
What does “flashed with the newest updates” mean?
Over the years, manufacturers like GM release software updates to fix bugs, improve transmission shifting, and enhance engine performance. We program your module with the latest official GM calibration available for your specific VIN, ensuring optimal operation.