Is Your Truck Running Rough? It Could Be The PCM.
If your 1999 GMC 1500 is experiencing baffling issues like a persistent check engine light, poor fuel economy, erratic shifting, or even a no-start condition, the root cause is often a failing Powertrain Control Module (PCM). As the central computer for your engine and transmission, the PCM’s health is critical for performance, efficiency, and reliability. When it begins to fail, it can send incorrect signals to vital components, leading to a cascade of problems that can be difficult to diagnose.
From the Diagnostic Bay
I once had a customer with a late-90s Chevy 2500, very similar to this platform, who had spent over a thousand dollars replacing sensors. He changed the O2 sensors, the MAP sensor, even the throttle position sensor, but the truck still idled poorly and guzzled gas. The check engine light was a permanent fixture on his dash. When he finally brought it to our shop, a quick scan showed multiple conflicting error codes—a classic sign of a confused computer. We swapped in a VIN-programmed PCM, and it was like a different truck. All the codes cleared, the idle smoothed out, and his fuel economy returned to normal. It’s a powerful reminder that sometimes the issue isn’t the sensors, but the brain reading them.
Symptoms of a Failing Powertrain Control Module
- ✔ Persistent Check Engine Light (CEL) with various, often unrelated, trouble codes.
- ✔ Noticeable decrease in fuel efficiency.
- ✔ Rough or inconsistent engine idling.
- ✔ Engine stalling or hesitation during acceleration.
- ✔ Harsh or erratic automatic transmission shifting.
- ✔ Failure to pass emissions tests.
- ✔ Complete no-start condition where the engine cranks but won’t fire up.
The Direct-Fit Solution: A Programmed 1999 GMC 1500 PCM
Don’t let a faulty computer keep your reliable truck off the road. This Powertrain Control Module is the definitive solution to restore your vehicle’s factory performance. We eliminate the guesswork and the need for expensive dealership visits. The process is simple: you provide us with your vehicle’s Vehicle Identification Number (VIN) after purchase, and we program the module with the latest official GM software updates specific to your truck. This ensures that all parameters for fuel delivery, ignition timing, and transmission control are perfectly calibrated for your exact configuration.
This module arrives at your door ready for installation. Simply disconnect the battery, remove the old PCM, install the new one, and reconnect the battery. In most cases, a simple security relearn procedure is all that’s needed to get you back on the road. This is a high-quality, reliable component designed to meet or exceed original equipment specifications, providing a long-lasting repair for your vehicle.
This unit is a direct replacement for multiple part numbers, including 16263494, 16265035, and 8162634940, and fits a wide range of GM trucks, vans, and SUVs from the era, such as the Chevrolet Silverado, Tahoe, Suburban, Express, S10, Blazer, and GMC Sierra, Yukon, Savana, and more. Please verify the part number ID on your original module to ensure compatibility.
Frequently Asked Questions
Do I need to get this PCM programmed?
No. This PCM comes fully programmed to your vehicle’s specific VIN. We handle all the flashing and software updates before it ships, so it’s ready to install right out of the box.
How do I provide my VIN?
After you complete your purchase, you can send us a message with your 17-digit VIN, or add it as a note during checkout. We cannot ship the module until we have your VIN to program it.
Where is the PCM located on my 1999 GMC 1500 Pickup?
On the 1999 GMC 1500, the PCM (also called the Electronic Control Module or ECM) is typically located in the engine compartment on the driver’s side (LH side), often near the battery or firewall.
Will I need to perform any other procedures after installation?
Yes, you will likely need to perform a security relearn procedure, also known as the Passlock relearn. This typically involves turning the key to the ‘ON’ position for 10 minutes, then ‘OFF’ for 10 seconds, and repeating this cycle three times. This syncs the new PCM with your vehicle’s anti-theft system.
Is this compatible with part number 16263494?
Yes, this module is a direct replacement for several part numbers, including 16263494. It serves as a consolidated replacement for many original units.