Is Your 1999 Chevy Truck Running Rough? The PCM Might Be the Culprit.
If you’re dealing with frustrating issues like poor fuel economy, erratic shifting, a persistent check engine light, or even a no-start condition in your GM truck or van, a failing Powertrain Control Module (PCM) is often the root cause. As the central computer of your vehicle, the PCM is responsible for managing everything from the fuel injectors and spark timing to the transmission shift points. When it begins to fail, it can create a cascade of problems that are difficult to diagnose and can mimic other component failures.
This replacement Powertrain Control Module is the definitive solution for restoring your vehicle’s performance and reliability. It is a direct-fit replacement for a wide range of GM vehicles from the late 90s and early 2000s, including the Chevrolet Silverado, GMC Sierra, Express/Savana vans, and more. We take the guesswork out of the repair by programming the module specifically for your vehicle using your VIN. This ensures that all factory settings and the latest GM software updates are loaded, making for a seamless, plug-and-play installation.
From the Diagnostic Bay
We had a 1999 GMC Sierra in the shop that was driving the owner crazy. It had a random, intermittent misfire that wouldn’t set a consistent code, and the transmission would sometimes shift hard into second gear. The owner had already replaced the spark plugs, wires, and even the transmission fluid and filter with no luck. After checking all the wiring and grounds, we hooked up our scope to the injector drivers. We noticed the signal from the PCM was dropping out intermittently on cylinder 3. We swapped in a pre-programmed PCM, and the truck immediately ran like new. It’s a classic case of a failing computer causing phantom mechanical issues that can lead you down an expensive rabbit hole of unnecessary repairs.
Symptoms of a Failing 1999 Chevrolet 1500 PCM
- ✔ Persistent Check Engine Light (CEL) with various trouble codes
- ✔ Engine stalling, stumbling, or misfiring
- ✔ Harsh or erratic automatic transmission shifting
- ✔ A sudden, unexplained drop in fuel mileage
- ✔ The engine cranks but refuses to start
- ✔ Failure to communicate with a diagnostic scan tool
- ✔ Issues with emissions testing
The Plug-and-Play Solution
Don’t waste time and money at a dealership for expensive programming. Our service simplifies the entire process. Once you purchase the module, simply provide us with your vehicle’s VIN. Our technicians will flash the unit with the correct, updated software specific to your truck’s engine, transmission, and options. When it arrives, all you need to do is disconnect the battery, swap the old module with the new one, and reconnect the battery. In most cases, the vehicle will start right up and run perfectly, with no additional security relearn procedures required.
This module is a direct replacement for multiple part numbers, including 16263494, 16265035, and 8162634940. Please verify the part number on your original module or consult the extensive fitment list to ensure compatibility with your specific make and model.
Frequently Asked Questions
Do I need to get this PCM programmed?
No. We handle all the programming for you before we ship the part. Just provide your vehicle’s VIN during or after checkout, and it will arrive ready to install.
Where is the PCM located on my 1999 Chevrolet 1500 Pickup?
On most 1999-2000 GMT400 and early GMT800 trucks like the Chevy 1500/Silverado, the PCM (or ECM) is located in the engine compartment, typically on the driver’s side, either on the inner fender or under the battery tray.
What is the difference between a PCM, ECM, and ECU?
ECU (Electronic Control Unit) is a generic term. ECM (Engine Control Module) specifically controls engine functions. A PCM (Powertrain Control Module) is an integrated unit that controls both the engine and the transmission. For this vehicle, the terms are often used interchangeably.
What information do you need from me?
We need your 17-digit Vehicle Identification Number (VIN) to ensure we load the correct factory software for your truck’s specific configuration.
Will this fix my check engine light?
If the check engine light is caused by a faulty PCM, then yes, this part will resolve the issue. However, it’s always recommended to have the codes professionally diagnosed to ensure the PCM is the true cause of the problem and not another sensor or component.