Restore Peak Performance to Your GM Truck or Van
Is your 1998-1999 GMC 1500 Pickup suffering from frustrating issues like a persistent Check Engine Light, poor fuel economy, or erratic engine behavior? The Powertrain Control Module (PCM), the electronic brain of your vehicle, is often the culprit. This replacement PCM, part number 16250279, is the definitive solution to restore your vehicle’s factory-spec operation and reliability. We take the guesswork and hassle out of the repair by pre-programming the module to your vehicle’s specific VIN before it ships. This ensures a seamless installation and proper communication with all other onboard systems.
From the Diagnostic Bay: The Ghost in the Machine
I remember a ’99 Chevy Suburban that came into my shop with a complaint that stumped two other mechanics. The owner said it would randomly refuse to start, but only when warm. There were no consistent trouble codes, just a sporadic U-series communication loss code. We checked all the usual suspects—battery, grounds, starter, fuel pump. Everything tested fine. After hooking up a scope, I noticed the 5-volt reference signal from the PCM would occasionally drop out during cranking. On these GMT400 platforms, heat soak can cause internal solder joints in the PCM to fail, creating these impossible-to-trace intermittent problems. A replacement, correctly programmed PCM fixed it instantly. That’s why a quality, properly configured 1998-1999 GMC 1500 PCM isn’t just a part—it’s peace of mind.
Is Your Truck Exhibiting These PCM Failure Signs?
A failing PCM can cause a wide range of symptoms that can be mistaken for other issues. If you’re experiencing any of the following, your engine computer is likely the cause:
- ✔ Check Engine Light is illuminated, often with codes like P0601 (Internal Control Module Memory Check Sum Error) or P0605 (Internal Control Module ROM Error).
- ✔ Vehicle will not start or has intermittent no-start conditions.
- ✔ Poor or declining fuel economy.
- ✔ Harsh or erratic automatic transmission shifting.
- ✔ Engine stalling, stumbling, or misfiring.
- ✔ Failure to pass an emissions test.
- ✔ Loss of communication with the scan tool.
A Straightforward Guide to Installation
Installing your new 1998-1999 GMC 1500 PCM is a manageable job for a confident DIYer. Since we program it beforehand, you won’t need any special scan tools for setup.
- Safety First: Always disconnect the negative terminal from your vehicle’s battery and secure it away from the post.
- Locate the PCM: On most GM trucks and SUVs of this era, the PCM is located in the engine bay, typically on the driver’s side inner fender or near the battery.
- Disconnect the Harnesses: Carefully unclip and remove the electrical wiring harnesses connected to the old module. These connectors have locking tabs that must be released to prevent damage.
- Remove the Old Module: Unbolt the old PCM from its mounting bracket. It’s usually held in place by a few small bolts.
- Install the New Module: Mount your new, pre-programmed PCM onto the bracket and secure it with the bolts.
- Reconnect Everything: Firmly plug the wiring harnesses back into the new PCM until they click into place. Reconnect the negative battery terminal.
- Final Steps: In some cases, a security relearn procedure may be necessary. This simple process typically involves turning the key to the ‘ON’ position for 10-15 minutes. Consult your vehicle’s service information for specific steps.
Verified Compatibility for Your GM Vehicle
This module is a direct replacement for service number 16250279 and is also compatible with part numbers 09366810 and 09355699. It is guaranteed to fit the following vehicles with the specified options. Always match your part number for a perfect fit.
Chevrolet/GMC Pickups (1500/2500/3500): 1998-1999 (Gasoline, ID 16250279)
Chevrolet/GMC Suburban (1500/2500): 1998-1999 (Gasoline, ID 16250279)
Chevrolet Tahoe / GMC Yukon: 1998-1999 (Gasoline, ID 16250279)
Chevrolet Astro / GMC Safari: 1998-1999 (ID 16250279)
Chevrolet Express / GMC Savana (1500/2500/3500): 1998 (Gasoline, ID 16250279)
Oldsmobile Bravada: 1998 (4.3L, w/o opt ZN4, ID 16250279 or 16258815)
Chevy S10 / GMC Sonoma / Jimmy / Blazer: 1998 (4.3L, w/o opt ZN4, ID 16250279 or 16258815)
GMC Envoy: 1998 (w/o opt ZN4, ID 16250279 or 16258815)
Isuzu Hombre: 1998 (4.3L, w/o opt ZN4, ID 16250279 or 16258815)
Frequently Asked Questions
Frequently Asked Questions
Do I need to do any programming myself?
No. We handle all the programming for you. Simply provide us with your vehicle’s 17-digit VIN during or after checkout, and we will flash the module with the latest GM software specific to your truck before shipping. It arrives ready for installation.
What is a security relearn procedure?
This is a simple, tool-free process that syncs the new PCM with your vehicle’s anti-theft system. For most GM vehicles of this era, it involves leaving the key in the ‘ON’ position for about 10-15 minutes. This is not always required but is a common final step.
Is this a direct replacement for my original part?
Yes, this unit is a direct replacement for OEM part number 16250279 and its alternates. As long as your vehicle is on the compatibility list and your original module carries one of the compatible part numbers, this will be a perfect fit.
How do I find my vehicle’s VIN?
Your VIN can be found on your vehicle’s registration, insurance card, or on a metal plate on the driver’s side of the dashboard, visible through the windshield.
Will this fix my check engine light?
If the Check Engine Light is caused by an internal failure of the PCM (e.g., codes P0601, P0605), then yes, this module will resolve the issue. It’s crucial to properly diagnose the problem first to ensure the PCM is the root cause.