Restore Your Vehicle’s Core Performance and Reliability
Is your trusty GM truck or van suddenly acting up? Unexplained stalling, a persistent check engine light, or erratic transmission shifting can be incredibly frustrating. As a technician with over 20 years of experience under the hood, I’ve seen these exact issues countless times. Often, the root cause isn’t a faulty sensor or a bad transmission solenoid—it’s the vehicle’s central computer, the Powertrain Control Module (PCM), that has failed. This module is the brain of your engine and transmission, and when it falters, the entire vehicle suffers. This listing is for a direct-replacement PCM, professionally flashed with the latest GM software updates specifically for your vehicle. Simply provide your VIN at checkout, and we’ll handle the programming, so it arrives ready to install.
From the Diagnostic Bay
I remember a 1999 GMC Sierra that came into the shop with a complaint of harsh, unpredictable shifting and a check engine light. The owner had already replaced the vehicle speed sensor and a shift solenoid with no luck. After connecting my scanner, I pulled a few generic transmission codes but also a P0601 (Internal Control Module Memory Check Sum Error). This code is a dead giveaway. The PCM’s internal memory was corrupted. We installed a VIN-programmed PCM just like this one, performed the security relearn, and the truck drove and shifted like it just rolled off the factory line. It’s a perfect example of how the right part, correctly programmed, is the only true fix.
Is Your Truck or Van Showing These Signs?
A failing PCM can cause a wide range of symptoms that can be easily mistaken for other issues. If you’re experiencing any of the following, your PCM could be the culprit:
- ✔ Persistent Check Engine Light that won’t clear
- ✔ Engine stalling, stumbling, or rough idling
- ✔ A no-start or difficult starting condition
- ✔ Decreased fuel economy
- ✔ Harsh or erratic automatic transmission shifting
- ✔ Failure to pass an emissions inspection
- ✔ Diagnostic Trouble Codes (DTCs) such as P0601, P0602, P0604, or P0606
Straightforward Guide to Installation
Replacing the 1999 GMC 1500 PCM is a job most DIYers can handle in their own driveway. Our VIN programming service makes it a true plug-and-play solution, eliminating the need for a costly trip to the dealership. Follow these general steps for a successful installation:
- Safety First: Always disconnect the negative terminal from your vehicle’s battery before beginning any electrical work.
- Locate the PCM: On most of these trucks and vans, the PCM is located in the engine compartment, typically on the driver’s side fender or near the battery. Refer to your vehicle’s service manual for the exact location.
- Disconnect Connectors: Carefully release the locking tabs and unplug the wiring harness connectors from the old module. Inspect the connectors for any corrosion or damage.
- Remove the Old Module: Unbolt the old PCM from its mounting bracket and remove it from the vehicle.
- Install the New Module: Mount your new, pre-programmed PCM into the bracket, and securely reconnect the wiring harnesses. You should hear a ‘click’ as they lock into place.
- Reconnect Battery: Reattach the negative battery terminal.
- Perform Security Relearn: Some GM vehicles of this era require a security relearn procedure to allow the vehicle to start. This simple procedure can typically be done with just the ignition key and takes about 30 minutes. Search for the “GM 30-minute security relearn procedure” for easy-to-follow instructions.
Verified Fitment for Your GM Vehicle
This module is a direct replacement for a wide range of GM vehicles and corresponds to part numbers 16263494, 16265035, 8162634940, and 218-11787. While the fitment list is extensive, key compatible models include:
- ✔ 1999-2000 Chevrolet & GMC C/K 1500, 2500, 3500 Pickups
- ✔ 1999-2000 Chevrolet Silverado & GMC Sierra 1500 (V6 models)
- ✔ 1999-2002 Chevrolet Express & GMC Savana Vans (1500/2500/3500)
- ✔ 1998-2000 Chevrolet S10, GMC Sonoma, Isuzu Hombre (4.3L)
- ✔ 1998-2000 Chevrolet Blazer, GMC Jimmy, Oldsmobile Bravada
- ✔ 1999-2000 Cadillac Escalade, Chevrolet Tahoe, GMC Yukon
- ✔ 1999-2001 Chevrolet Astro & GMC Safari Vans
To ensure perfect compatibility, please verify your vehicle is on the detailed fitment list and provide your VIN upon purchase. This is the best way to guarantee you receive the correct, plug-and-play 1999 GMC 1500 PCM for your specific application.
Frequently Asked Questions
What exactly does a PCM do?
The Powertrain Control Module (PCM) is your vehicle’s main computer. It controls everything from fuel injection and ignition timing to transmission shift points and emissions systems, ensuring your engine runs efficiently and smoothly.
Why is providing my VIN so important?
Your Vehicle Identification Number (VIN) allows us to flash the module with the exact GM factory software for your truck’s specific engine, transmission, and options. This ensures seamless integration and proper function without any additional programming required on your end.
Is this part difficult to install for a DIYer?
Not at all. The physical replacement is straightforward, involving a few bolts and electrical connectors. Because we program it for you, you skip the most complicated part. The only extra step might be a simple security relearn procedure you can do with your key.
Will this fix my check engine light?
If the check engine light is caused by an internal PCM failure (like DTC P0601), then yes, this module is the correct fix. However, it’s always best to have the codes read by a scanner to confirm the source of the problem before ordering parts.
What if my original part number is slightly different but my vehicle is listed?
GM often uses several interchangeable part numbers for the same component. This module replaces multiple part numbers, including 16263494 and 16265035. As long as your vehicle model and year are on our compatibility list, providing your VIN will guarantee we send you the correct programmed unit.