Restore Your Truck’s Performance and Reliability
Is your Chevrolet, GMC, or Cadillac truck or van running rough, shifting erratically, or refusing to start? A failing Powertrain Control Module (PCM) is often the culprit. As a technician with over two decades of experience under the hood, I’ve seen firsthand how a faulty PCM can cause a cascade of frustrating issues, from a persistent Check Engine Light to poor fuel economy. This isn’t just an inconvenience; it’s a problem that affects your vehicle’s core performance and safety. This replacement PCM, part number 16265035, is the definitive solution to get your workhorse back on the road, running like it should.
What sets this module apart is our commitment to a hassle-free installation. We take care of the most critical step for you: programming. Before we ship, we flash the module with the latest GM-certified software, specifically matched to your vehicle using the VIN you provide. This means you can skip the expensive trip to the dealership and the need for specialized scan tools. This is a direct-fit, plug-and-play solution designed for both professional mechanics and dedicated DIYers.
Case Study: A Tricky Diagnosis
I once had a 2000 GMC Sierra in my bay with an intermittent no-start and a random stalling issue that no one could figure out. The owner had already replaced the fuel pump and crank sensor. After connecting my scanner, I saw no communication with the PCM. A quick check of the powers and grounds to the module confirmed they were good. The diagnosis was clear: an internal failure in the original PCM. We ordered one of these pre-programmed modules, and once it arrived, the installation took less than 30 minutes. The truck fired right up and ran perfectly. The pre-flashing saved the customer hundreds in dealership programming fees and got his truck back to him the same day the part arrived.
Signs Your Powertrain Module Needs Attention
A failing PCM can manifest in various ways. If you’re experiencing any of the following, it’s a strong indicator that the brain of your engine is in trouble. A faulty 1999-2000 Chevrolet 2500 PCM can be the root cause of many headaches.
- ✔ Persistent Check Engine Light (CEL)
- ✔ Diagnostic Trouble Codes (DTCs) such as P0601, P0604, or P0606
- ✔ Vehicle won’t start or is very difficult to start
- ✔ Rough idling or stalling
- ✔ Poor fuel mileage
- ✔ Harsh or erratic automatic transmission shifting
- ✔ Failure to pass emissions testing
A Straightforward Guide to Installation
Installing your new PCM is a manageable job for anyone with basic tools. Because we program it beforehand, you avoid the complex steps. Here’s a general guide:
- Safety First: Always disconnect the negative terminal from your vehicle’s battery and wait 10-15 minutes for the system to fully discharge.
- Locate the PCM: On most of these trucks and vans, the PCM is located in the engine compartment, often on the driver’s side fender or near the battery. Check your specific model’s service manual for the exact location.
- Disconnect Connectors: Carefully unclip the wiring harness connectors from the old module. These connectors have locking tabs that may need to be gently pried or squeezed to release. Inspect them for any corrosion or damage.
- Remove the Old Module: Unbolt the old PCM from its mounting bracket. It’s typically held in by a few bolts or nuts.
- Install the New PCM: Mount your new, pre-programmed module in place and secure it with the original hardware.
- Reconnect Everything: Firmly plug the wiring harness connectors into the new PCM until they click into place. Reconnect the negative battery terminal.
- Perform Security Relearn (If Needed): On some models, you may need to perform a simple security relearn procedure. This usually involves turning the key to the ‘ON’ position for 10-15 minutes. We include specific instructions if this is required for your vehicle.
Verified Vehicle Compatibility
This module is a direct replacement for service number 16265035 and is also compatible with part numbers 16263494, 8162634940, 218-11787, and 21811787. It fits a wide range of GM gasoline-powered vehicles. Please match your vehicle, year, and original part number below to ensure a perfect fit. Providing your VIN during checkout is essential for correct programming.
CHEVROLET 1500 PICKUP 99 (5.0L, 5.7L)
CHEVROLET 3500 PICKUP 99-00 (Gasoline)
SILVERADO 1500 PICKUP 99-00 (4.3L V6)
SUBURBAN 1500/2500 99 (Gasoline)
TAHOE 99-00 (Classic Style)
ASTRO VAN 99-01
BLAZER S10 98-00
EXPRESS VAN 1500/2500/3500 99-02 (Gasoline)
S10 PICKUP 98-00 (4.3L)
GMC 1500 PICKUP 99 (5.0L, 5.7L)
GMC 2500 PICKUP 99-00 (Gasoline)
GMC 3500 PICKUP 99-00 (Gasoline)
SIERRA 1500 PICKUP 99-00 (4.3L V6)
YUKON / YUKON DENALI 99-00
JIMMY S15 98-00
SAFARI VAN 99-01
SAVANA VAN 1500/2500/3500 99-02 (Gasoline)
CADILLAC ESCALADE 99-00
ISUZU HOMBRE 98-00 (4.3L)
OLDSMOBILE BRAVADA 98-00
ENVOY 98-00
Note: Some 1998 models require build date option ZN4. Please verify fitment.
Frequently Asked Questions about this PCM
Frequently Asked Questions
What information do you need to program my PCM?
We require your vehicle’s 17-digit Vehicle Identification Number (VIN) to ensure the module is flashed with the correct software for your specific engine, transmission, and options.
Is this a simple plug-and-play installation?
Yes! Because we program the module to your VIN before shipping, it arrives ready to install without needing a trip to the dealer for additional flashing. In some cases, a simple key-cycle security relearn may be needed, and we provide instructions for that.
Will this fix my transmission shifting problems?
In many cases, yes. The PCM controls both engine and transmission functions. If the module is failing, it can cause poor shift quality, hunting for gears, or delayed engagement. Replacing a faulty PCM often resolves these issues.
How do I know if my original PCM is part number 16265035?
The part number is printed on a sticker on the case of your original module. This module is a direct replacement for 16265035 and several other compatible part numbers listed in the description.
What if I have questions during installation?
Our team of experts is here to help. We provide support to ensure you can get the job done right, making this the best solution for your 1999-2000 Chevrolet 2500 PCM replacement.