Restore Your Truck’s Performance and Reliability
Is your 1999-2000 GMC 3500 Pickup running rough, stalling unexpectedly, or refusing to start? A faulty Powertrain Control Module (PCM), the electronic brain of your engine, is often the culprit behind these frustrating and hard-to-diagnose issues. As a technician with over 20 years of experience, I’ve seen firsthand how a failing PCM can mimic a dozen other problems, leading to wasted time and money on unnecessary parts. This replacement PCM is your direct, reliable solution to get your workhorse truck back on the road, performing as it should.
This isn’t just a replacement part; it’s a complete, ready-to-install solution. We professionally program this module to your truck’s specific Vehicle Identification Number (VIN) before it ships. This process ensures perfect compatibility and installs the latest GM factory software updates, which can correct performance issues you didn’t even know were software-related. Forget expensive dealership visits for programming—this module arrives ready for installation right out of the box.
Case Study: A Tricky Diagnosis
A customer brought in his 2000 Chevy 3500 work truck with a complaint of intermittent stalling and a random ‘no-start’ condition that would happen once or twice a week. He had already replaced the fuel pump and crank sensor with no luck. The check engine light was on, but the codes were inconsistent. After connecting my scan tool, I noticed fluctuating data from several sensors simultaneously, which is a classic sign of a processor issue. The key code that pointed me in the right direction was a P0601 (Internal Control Module Memory Check Sum Error). This confirmed the internal circuitry of the original PCM was failing. We installed a VIN-programmed module just like this one, performed the security relearn, and the truck has run flawlessly ever since. It’s a textbook example of how a faulty 1999-2000 GMC 3500 PCM can create a diagnostic nightmare that only the correct part can solve.
Is Your Truck Showing These Symptoms?
A failing PCM can cause a wide range of issues. If you’re experiencing any of the following, this module is the likely solution:
- ✔ Check Engine Light is on with codes like P0601, P0604, or P0606
- ✔ Engine cranks but will not start
- ✔ Intermittent stalling or rough idling
- ✔ Poor fuel economy and loss of power
- ✔ Harsh or incorrect automatic transmission shifting
- ✔ Communication errors with scan tools
- ✔ Seeming failure of multiple unrelated sensors at once
A Straightforward Guide to Installation
Installing your new 1999-2000 GMC 3500 PCM is a manageable job for a DIYer with basic tools. Follow these steps for a successful replacement.
- Safety First: Disconnect the negative terminal from your truck’s battery to prevent any electrical shorts.
- Locate the PCM: On most of these trucks, the PCM is located in the engine compartment, typically on the driver’s side (LH) fender well or near the battery.
- Disconnect the Harnesses: Carefully unclip and remove the electrical wiring harnesses connected to the old module. These connectors have locking tabs that need to be released gently.
- Remove the Old Module: Unbolt the old PCM from its mounting bracket. Keep the hardware as you may need it for the new module.
- Install the New PCM: Mount the new, pre-programmed module in the same location and securely reconnect the wiring harnesses. Ensure they click into place.
- Reconnect the Battery: Reattach the negative battery terminal.
- Perform Security Relearn: You will likely need to perform a security or anti-theft relearn procedure (often called the CASE relearn). This simple process typically involves turning the key to the ‘ON’ position for 10-15 minutes, then off, and repeating two more times. This allows the vehicle’s security system to recognize the new PCM.
Verified Vehicle Compatibility
This module is a direct replacement for part numbers 16263494, 16265035, 8162634940, 218-11787, and 21811787. It is guaranteed to fit the following vehicles, but please verify your specific options. Providing your VIN at checkout is the best way to ensure 100% compatibility.
– 1999-2000 GMC/Chevy 3500 Pickup (Gasoline)
– 1999-2000 GMC/Chevy 2500 Pickup (Gasoline)
– 1999-2000 Sierra/Silverado 1500 (4.3L V6)
– 1999 GMC/Chevy 1500 Pickup (5.0L or 5.7L, ID 16263494)
GMC / Chevrolet Vans:
– 1999-2002 Express/Savana 1500, 2500, 3500 (Gasoline)
– 1999-2001 Astro/Safari (4.3L, ID 16263494)
GMC / Chevrolet SUVs & S-Series:
– 1999-2000 Tahoe/Yukon (incl. Denali, Classic Style)
– 1999 Suburban 1500/2500 (Gasoline, ID 16263494)
– 1998-2000 Blazer/Jimmy/Bravada/Envoy (4.3L)
– 1998-2000 S10/S15/Sonoma (4.3L)
Cadillac / Isuzu:
– 1999-2000 Escalade
– 1998-2000 Isuzu Hombre (4.3L)
Frequently Asked Questions
Frequently Asked Questions
Do I really need to provide my VIN?
Yes, absolutely. Providing your VIN is critical. We use it to load the exact, correct software calibration from GM for your truck’s specific engine, transmission, and emissions equipment. This guarantees compatibility and proper function without a trip to the dealer.
Is this module difficult to install?
The physical installation is straightforward for most DIYers. It involves disconnecting the battery, unplugging a few connectors, and swapping the module. The only extra step is the security relearn procedure, which does not require special tools and can be found in many online forums or videos for your specific model.
Will this fix my transmission shifting problems?
It very well could. The PCM controls both engine functions and transmission shift points. If the module is failing, it can send incorrect signals to the transmission, causing harsh or erratic shifting. A new, correctly programmed PCM often resolves these types of electronic transmission issues.
What does ‘flashed with the newest updates’ mean?
Over the life of a vehicle, manufacturers like GM release software updates to fix bugs, improve drivability, or enhance efficiency. When we program your module, we ensure it’s loaded with the very latest software version available for your VIN, giving you benefits the original module never had.