Is Your GM Truck or Van Running Rough?
There’s nothing more frustrating than a vehicle you can’t rely on. If your 1998 or 1999 GM truck or van is experiencing baffling issues like stalling, erratic idling, a persistent check engine light, or simply won’t start, the problem often points to a failing Powertrain Control Module (PCM). The PCM is the electronic brain of your vehicle, managing everything from fuel injection and spark timing to transmission shifting. When it starts to fail, it can create a cascade of problems that are difficult to diagnose and can sideline your vehicle indefinitely.
From the Diagnostic Bay
We had a 1998 GMC Jimmy come into the shop that was driving the owner crazy. It would run perfectly for days, then suddenly stall at a stoplight and refuse to restart for 20 minutes. No specific codes were being stored, just a generic communication error now and then. After checking all the usual suspects—fuel pump, ignition system, grounds—we hooked up a scope to the injector drivers at the PCM. Sure enough, we saw the signal drop out intermittently as the module warmed up. A replacement, programmed PCM like this one had the Jimmy running reliably in under an hour (plus the 30-minute security relearn). It’s often the component people suspect last, but it’s the central hub for the entire powertrain.
Symptoms of a Failing PCM
- ✔ Check Engine Light is on with codes related to PCM internal failure or communication errors (e.g., P0600-P0606).
- ✔ Engine cranks but refuses to start.
- ✔ Intermittent stalling, especially after the vehicle has warmed up.
- ✔ Rough or unstable engine idle.
- ✔ Noticeable decrease in fuel economy.
- ✔ Harsh or erratic automatic transmission shifting.
- ✔ Failure to communicate with a diagnostic scan tool.
Your Direct-Fit, Programmed Solution: The 1998 S10 PCM
Don’t let a faulty computer keep you off the road. This is a thoroughly tested, genuine GM Powertrain Control Module that offers a reliable and cost-effective solution. We take the guesswork and hassle out of the repair by pre-programming the unit specifically for your vehicle. When you place your order, you provide us with your vehicle’s VIN. Our technicians then use that information to flash the module with the latest, most up-to-date GM factory software for your exact make, model, and engine configuration. This ensures perfect compatibility and optimal performance right out of the box.
This module, identified by part numbers 09366810 and 09355699, is a direct replacement for a wide range of popular 1998-1999 GM vehicles, including the Chevrolet S10, GMC Sonoma, Blazer, Jimmy, Tahoe, Suburban, Express, Savana, and many more. Please verify your part number or consult the detailed fitment list to confirm compatibility.
Installation is Straightforward
Physically swapping the module is typically a simple process involving disconnecting the battery, unplugging the electrical connectors, and removing a few mounting bolts. Once the new module is installed, you will need to perform a security relearn procedure (often called VATS or Passlock). This is a simple process that pairs the new PCM to your vehicle’s anti-theft system and does not require any special tools. A common procedure involves turning the key to the ‘ON’ position for 10 minutes, then ‘OFF’ for 10 seconds, and repeating this cycle three times. We include instructions to make this final step as easy as possible.
Frequently Asked Questions
What is a PCM and what does it do?
The Powertrain Control Module (PCM) is your vehicle’s main computer. It controls all aspects of the engine and transmission to ensure optimal performance, fuel efficiency, and emissions.
Do I need to take this to a dealer for programming?
No! That’s the best part. We program the computer for you using your VIN before we ship it. It arrives ready for installation and the security relearn procedure.
Is this a plug-and-play part?
It is a direct physical fit and is electronically programmed for your vehicle. However, you must perform a security relearn procedure after installation to sync the PCM with your vehicle’s anti-theft system. Instructions are provided.
How do I find my original part number?
The part number is printed on a sticker on the case of your existing PCM. It will typically be a multi-digit number, such as 09366810 or 16266645.
What is the security relearn procedure?
It’s a simple process to sync the new computer to your vehicle. It typically involves cycling the ignition key on and off in a specific 30-minute sequence. This procedure ensures that only your keys can start the vehicle.
Will this PCM fit vehicles other than the S10/Sonoma?
Yes, absolutely. This module fits a very wide range of 1998-1999 GM trucks and vans, including the Tahoe, Suburban, C/K pickups, Express/Savana vans, and more. Please check the detailed fitment list on this page to confirm for your specific model.