Is Your 1998 GM Truck or SUV Running Rough? The PCM Might Be the Culprit.
If you’re dealing with a check engine light that won’t go away, erratic engine behavior, poor fuel economy, or even a no-start condition in your 1998 Chevy Blazer, GMC Jimmy, or other compatible GM vehicle, a failing Powertrain Control Module (PCM) is a likely cause. The PCM is the electronic brain of your vehicle, responsible for managing everything from fuel injection and ignition timing to transmission shifting. When it starts to fail, it can create a cascade of frustrating and difficult-to-diagnose problems. Don’t let a faulty computer keep your reliable truck off the road. This replacement PCM is the reliable, cost-effective solution you need.
The Direct-Fit Solution: A Pre-Programmed 1998 Blazer S10 PCM
Replacing a PCM isn’t as simple as swapping out a battery. The module must be correctly programmed to your vehicle’s specific Vehicle Identification Number (VIN) to communicate with the other systems on board. This unit solves that problem. We take a quality, road-tested, used PCM and flash it with the latest official GM software updates specifically for your vehicle. All you need to do is provide us with your VIN after purchase, and we handle the complex programming before it ever leaves our facility. This ensures a smoother installation process and restores the original factory performance and functionality your vehicle was designed to have.
From the Diagnostic Bay
I once had a 1998 GMC Yukon come into the shop with a complaint of a harsh 1-2 shift and an intermittent stall at idle. The customer had already replaced the transmission fluid, filter, and even a few sensors, but the problem persisted. The scanner showed no hard codes, just some strange data readings from the throttle position sensor. After chasing our tails for a few hours, we hooked up a scope to the PCM’s 5-volt reference circuit and saw a noisy, unstable signal. The PCM’s internal voltage regulator was failing, causing the sensors to send bad data and the transmission to shift poorly. We installed a VIN-programmed PCM just like this one, performed the security relearn, and the truck ran like it just rolled off the assembly line. It’s a perfect example of how a single failing module can mimic a dozen other problems.
Common Symptoms of a Failing PCM
- ✔ Persistent Check Engine Light (CEL) with various trouble codes
- ✔ Engine stalling, stumbling, or misfiring
- ✔ Harsh or erratic automatic transmission shifting
- ✔ A significant drop in fuel economy
- ✔ The engine cranks but refuses to start
- ✔ Communication errors with diagnostic scan tools
- ✔ Failure to pass an emissions or smog test
Installation and Compatibility
This PCM, identified by part number 16266645 and service number 09355699, is a direct replacement for a wide range of 1998 and 1999 GM trucks, vans, and SUVs. Please verify your original part number or consult the detailed fitment list below to ensure compatibility. Installation is straightforward for a DIY mechanic with basic tools. After disconnecting the battery, you’ll locate your old PCM, disconnect the electrical harnesses, unbolt it, and install the new one in its place. Once installed and the battery is reconnected, you will need to perform a simple security relearn procedure (often called VATS or Passlock relearn) to sync the new PCM with your vehicle’s anti-theft system. This procedure typically involves turning the key to the ‘ON’ position for 10-15 minutes and can be done without special tools.
This module is a direct replacement for the following part numbers: 09355699, 16266645, 9355699, 16250279, 16258815, 09366810, 9366810.
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 the engine’s fuel delivery, spark timing, and emissions systems, as well as the transmission’s shifting, to ensure optimal performance, fuel efficiency, and low emissions.
How do I provide my vehicle’s VIN?
After you complete your purchase, you will receive instructions on how to send us your 17-digit VIN. We cannot ship your part until we receive this information, as the programming is essential for the part to function in your vehicle.
Do I need to do anything after installing this PCM?
Yes. After installation, you must perform a security relearn procedure, also known as a VATS or Passlock relearn. This allows the new PCM to recognize your vehicle’s anti-theft system and keys, enabling the vehicle to start. This procedure does not require special tools and instructions can be easily found online for your specific model.
Is this a new part?
No, this is a high-quality, genuine GM part sourced from a salvaged vehicle. Each unit is thoroughly inspected and tested before being programmed with the latest GM software for your specific VIN, ensuring reliable performance.
Will this computer fit vehicles other than a 1998 Blazer or Jimmy?
Absolutely. This PCM fits a very wide range of GM vehicles from 1998-1999, including the Chevy/GMC 1500/2500/3500 Pickups, Tahoe, Suburban, Yukon, Express/Savana vans, and more. Please refer to the detailed fitment information in the product description and match your original part number to ensure compatibility.