Is Your Truck Running Rough? The PCM Might Be the Culprit.
The Powertrain Control Module, or PCM, is the central computer of your 1999-2000 GMC 2500. It’s the brain behind the entire operation, managing everything from fuel mixture and ignition timing to transmission shift points and emissions controls. When this critical component begins to fail, it can cause a wide range of frustrating and often difficult-to-diagnose problems. Your reliable workhorse can quickly become an unpredictable headache, leaving you stranded or facing a failed emissions test. This replacement module is the definitive solution to restore your truck’s factory performance and reliability.
From the Diagnostic Bay
We recently had a 2000 Chevy 2500 (which uses this exact PCM) come into the shop with a persistent random misfire code (P0300) and a complaint of poor power under load. The owner had already replaced the spark plugs, wires, distributor cap, and rotor with no improvement. After confirming fuel pressure and checking for vacuum leaks, our diagnostics led us to the PCM itself. The internal ignition control driver was failing intermittently, causing the misfire. Installing a correctly programmed PCM like this one solved the problem immediately. It’s a reminder that what seems like a simple ignition issue can often be traced back to the vehicle’s computer.
Symptoms of a Failing 1999-2000 GMC 2500 PCM
A failing PCM can manifest in numerous ways. If you’re experiencing any of the following issues, a faulty engine computer could be the root cause. Look for these common warning signs:
- ✔ Persistent Check Engine Light (CEL) that won’t clear, or clears and returns quickly.
- ✔ Engine stalling, stumbling, or hesitating during acceleration.
- ✔ Rough or erratic idling.
- ✔ Noticeable decrease in fuel economy.
- ✔ Harsh or delayed automatic transmission shifting.
- ✔ Complete no-start condition where the engine cranks but won’t fire up.
- ✔ Failure to pass state emissions testing due to communication errors or specific trouble codes.
- ✔ Inconsistent performance that seems to change with temperature.
A Plug-and-Play Solution Programmed for Your Truck
Don’t settle for a generic, unprogrammed module from a salvage yard that will cause more problems than it solves. This Powertrain Control Module is a direct-fit replacement for your original unit. The key to our service is that we program the module specifically for your truck using the Vehicle Identification Number (VIN) you provide. This process ensures that the module has the latest software updates from GM and is perfectly matched to your truck’s engine, transmission, and factory options. This VIN-specific programming is critical for proper operation and eliminates the need for expensive dealership programming.
This module is a direct replacement for multiple part numbers, including 16263494, 16265035, and 8162634940. It fits a wide variety of GM trucks and vans from this era, including the Chevrolet Silverado, Express, Tahoe, Suburban, and GMC Sierra, Savana, and Yukon. By providing your VIN, you guarantee you receive a module that is 100% compatible and ready for installation right out of the box.
Frequently Asked Questions
Do I need to have this PCM programmed?
No. We handle the programming for you before we ship the part. Simply provide us with your vehicle’s 17-digit VIN during or after checkout, and the module will arrive ready to install with the latest GM software for your specific truck.
What is a CASE relearn and will I need to do one?
A CASE (Crankshaft Angle Sensor Error) relearn synchronizes the new PCM with your engine’s crankshaft position sensor. While not always required, it is recommended for optimal performance and to prevent a P1336 trouble code. Many high-end scan tools can perform this procedure, or a qualified mechanic can do it for you.
Will this fix my check engine light?
If the check engine light is caused by an internal failure of your existing PCM, then yes, this replacement module will resolve the issue. However, it’s crucial to ensure that the codes are not being caused by other faulty components like sensors or wiring.
Where is the PCM located on my 1999-2000 GMC 2500?
On most GMC and Chevrolet pickups from this generation, the PCM is located in the engine compartment on the driver’s side, typically near the fender or firewall. It’s a silver metal box with multiple large electrical connectors.
Is this a simple plug-and-play installation?
Yes, the physical installation is straightforward. After disconnecting the battery, you simply unplug the electrical connectors from the old module, unbolt it, and install the new one in its place. Because we program it beforehand, no dealer visit is necessary for software flashing.