Restore Peak Performance to Your GM Vehicle
Is your 1998-1999 GMC Safari, or another classic GM truck or van, suffering from frustrating issues like a persistent Check Engine Light, erratic shifting, or a no-start condition? As a technician with over two decades of experience, I’ve seen countless drivers chase these problems by replacing sensors and other parts, only to find the root cause was a failing Powertrain Control Module (PCM). This module is the brain of your vehicle, and when it falters, nothing else works correctly. This isn’t just a replacement part; it’s a direct solution to restore your vehicle’s reliability and drivability.
Case Study: A Tricky Diagnosis
I remember a 1999 GMC Sierra 1500 that came into the shop with a complaint of intermittent stalling and a transmission that shifted harshly. The owner had already replaced the throttle position sensor and the mass air flow sensor based on some forum advice. The codes were all over the place. After checking the wiring and grounds, my gut told me to look at the PCM. We hooked up a scope and saw the 5-volt reference signal dropping out randomly. A new, properly programmed PCM fixed everything instantly. The old module’s internal voltage regulator was failing, a common issue in these units after 20+ years of heat cycles. This part solves that exact problem.
Is Your GM Vehicle Showing These Signs?
A failing PCM can cause a wide array of symptoms that are often misdiagnosed. If you’re experiencing any of the following, this module is the likely solution:
- ✔ Persistent Check Engine Light (CEL)
- ✔ Diagnostic Trouble Codes (DTCs) related to internal module failure, such as P0601, P0604, or P0606
- ✔ Unexplained poor fuel economy
- ✔ Harsh or erratic automatic transmission shifting
- ✔ Engine stalling, stumbling, or refusing to start
- ✔ Communication errors with scan tools
The Simplest Way to Replace Your PCM
Forget expensive dealership visits and programming fees. We make this process straightforward. This 1998-1999 GMC Safari PCM arrives at your door pre-programmed with the latest official GM software updates, tailored specifically to your vehicle’s Vehicle Identification Number (VIN). This ensures perfect communication between your engine, transmission, and other onboard systems. It’s a true plug-and-play solution designed for both professional mechanics and DIY enthusiasts.
A Straightforward Guide to Installation
Installing your new PCM is a manageable job for anyone with basic hand tools. Follow these steps to get your vehicle back on the road quickly.
- Safety First: Always disconnect the negative terminal from your vehicle’s battery before starting any electrical work.
- Locate the Module: On most of these GM trucks and vans, the PCM is located in the engine bay, often on a fender well near the battery. It’s a metal box with several large electrical connectors.
- Disconnect and Remove: Carefully unplug the wiring harness connectors. They have locking tabs that may need to be squeezed or lifted. Once disconnected, unbolt the old module from its bracket and remove it.
- Install the New PCM: Mount your new, pre-programmed PCM onto the bracket. Ensure it is secure.
- Reconnect Everything: Firmly plug the wiring harness connectors into the new module. You should feel or hear a click as they lock into place. Reconnect the negative battery terminal.
- Final Check: Turn the key to the ‘On’ position for 10-15 seconds before starting the engine. This allows the system to initialize. Start your vehicle and check for proper operation. The Check Engine Light should be off.
Verified Vehicle Compatibility
This module, service number 09355699, is a direct replacement for part numbers 16250279 and 09366810. Please verify your original part number or match your vehicle from the list below to ensure compatibility.
- Cadillac Escalade: 1999
- Chevrolet Astro / GMC Safari: 1998-1999
- Chevrolet / GMC C/K Pickups (1500, 2500, 3500): 1998-1999 (Gasoline engines)
- Chevrolet / GMC Suburban (1500, 2500): 1998-1999 (Gasoline engines)
- Chevrolet Tahoe / GMC Yukon: 1998-1999
- Chevrolet Express / GMC Savana (1500, 2500, 3500): 1998 (Gasoline engines)
- Chevrolet S10 / GMC Sonoma / Isuzu Hombre: 1998 (4.3L V6)
- Chevrolet Blazer / GMC Jimmy / Oldsmobile Bravada / GMC Envoy: 1998 (4.3L V6)
Frequently Asked Questions
Frequently Asked Questions
How do I provide my VIN for programming?
After you complete your purchase, you will receive instructions to send us your 17-digit VIN. We cannot ship your order until we receive this information, as the programming is essential for the module to work in your vehicle.
Is any additional programming needed after installation?
No. This module is sent to you fully programmed and ready for installation. In most cases, no security relearn or other procedures are necessary. Just install it and drive.
What is the difference between a PCM, ECM, and ECU?
The terms are often used interchangeably. ECM (Engine Control Module) typically just controls engine functions. PCM (Powertrain Control Module) controls both the engine and the transmission. This part is a PCM that manages your vehicle’s complete powertrain.
Does this module replace part number 16250279?
Yes, this part is a fully compatible, direct replacement for service numbers 16250279, 09366810, and 09355699. We load the correct software for your specific vehicle based on your VIN.
What if my original part number isn’t listed?
If your part number or vehicle is not on our list, please contact us with your VIN before ordering. We can verify compatibility to ensure you receive the correct part for your specific application.