Restore Peak Performance to Your GM Truck or Van
If your 1999-2000 GMC Sierra 1500 is suffering from frustrating issues like intermittent stalling, poor fuel mileage, erratic shifting, or a persistent Check Engine Light, the problem often traces back to a failing Powertrain Control Module (PCM). As a technician with over two decades of experience, I’ve seen firsthand how a faulty PCM—the ‘brain’ of your vehicle’s engine and transmission—can cause a host of problems that seem impossible to pin down. This isn’t just an inconvenience; it affects your truck’s reliability, power, and fuel efficiency.
This isn’t a generic, off-the-shelf part. We offer a direct-fit replacement PCM, part number 16265035, that is professionally programmed to your vehicle’s specific Vehicle Identification Number (VIN) before it ships. This crucial step ensures seamless communication with all your truck’s systems, just like the original module from the factory. By loading the latest GM software updates, we also help resolve many of the common drivability issues that plagued these vehicles. You get a reliable solution that restores function without the exorbitant cost and hassle of a dealership visit.
Case Study: The Ghost in the Machine
A Technician’s Notebook: I had a 2000 Chevy Silverado (which uses the same platform as the Sierra) in my bay that was driving the owner crazy. It had a random no-start condition—it would be fine for weeks, then refuse to crank. No codes were stored consistently. After checking all the usual suspects—battery, starter, ignition switch—I focused on the PCM. On these GMT800 platforms, I’ve seen the internal circuit boards develop microscopic cracks from years of heat and vibration, causing intermittent connection failures. We swapped in a VIN-programmed PCM, and the ‘ghost’ was gone. The truck has been starting reliably for over a year. It’s a classic failure mode for this era of 1999-2000 Sierra 1500 PCM.
Is Your Truck Showing These Symptoms?
- ✔️ Persistent Check Engine Light (CEL)
- ✔️ Diagnostic Trouble Codes (DTCs) such as P0601 (Internal Control Module Memory Check Sum Error) or P0606 (PCM Processor Fault)
- ✔️ Unexplained stalling or engine hesitation
- ✔️ Harsh or delayed transmission shifting
- ✔️ A noticeable drop in fuel economy
- ✔️ Failure to pass state emissions testing
- ✔️ Vehicle won’t start, but the battery and starter are good
A Straightforward Guide to Installation
Replacing the PCM on your Sierra or similar GM truck is a job most DIYers can handle in their own driveway. Our VIN programming makes it a true plug-and-play process.
- Safety First: Disconnect the negative terminal from your vehicle’s battery and secure it away from the post.
- Locate the PCM: On most 1999-2000 Sierra/Silverado models, the PCM is located in the engine compartment on the driver’s side, often under or near the battery tray.
- 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.
- Remove the Old Module: Unbolt the old PCM from its mounting bracket.
- Install the New PCM: 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 the Battery: Re-attach the negative battery terminal.
- Security Relearn (If Necessary): In some cases, a simple security relearn procedure is required. This typically involves turning the key to the ‘ON’ position for 10-15 minutes. We include specific instructions if this is needed for your vehicle.
Verified Vehicle Compatibility
This module is a direct replacement for part numbers 16263494, 16265035, 8162634940, 218-11787, and 21811787. It fits a wide range of GM trucks and vans. Please verify your vehicle from the list below. After purchase, simply provide your VIN for programming.
CHEVROLET 2500 PICKUP 00 Electronic Control Module; gasoline (LH front engine compartment)
EXPRESS 1500 VAN 00-02 Electronic Control Module; (LH rear engine compartment)
EXPRESS 2500 VAN 00-02 Electronic Control Module; (LH rear engine compartment), gasoline
EXPRESS 3500 VAN 00-02 Electronic Control Module; (LH rear engine compartment), gasoline
SAVANA 1500 VAN 00-02 Electronic Control Module; (LH rear engine compartment)
ASTRO 99-01 Electronic Control Module; (LH front by battery), ID 16263494
GMC 3500 PICKUP 00 Electronic Control Module; gasoline (LH front engine compartment)
S10/S15/SONOMA 98-00 Electronic Control Module; (RH front engine compartment), 4.3L
ISUZU HOMBRE 98-00 Electronic Control Module; (RH front engine compartment), 4.3L
SAFARI (GMC) 99-01 Electronic Control Module; (LH front by battery), ID 16263494
GMC 1500 PICKUP 99 Electronic Control Module; 5.0L or 5.7L, (LH engine compartment), ID 16263494
BLAZER S10/JIMMY S15 98-00 Electronic Control Module; (RH front engine compartment)
TAHOE 00 Electronic Control Module; Classic style (LH front engine compartment)
YUKON 99 Electronic Control Module; (LH engine compartment), ID 16263494
ESCALADE 99-00 Electronic Control Module; (LH front under battery)
YUKON 00 Electronic Control Module; Denali (LH front under battery)
BRAVADA 98-00 Electronic Control Module; (RH front engine compartment)
ENVOY 98-00 Electronic Control Module; (RH front engine compartment)
SIERRA 1500 PICKUP 99-00 Electronic Control Module; (LH front under battery), 6 cylinder
SILVERADO 1500 PICKUP 99-00 Electronic Control Module; (LH front under battery), 6 cylinder
And many more models from 1998-2002. Please check the detailed fitment list or contact us with your VIN.
Frequently Asked Questions
Why do you need my VIN?
Your Vehicle Identification Number (VIN) contains critical information about your truck’s specific options, engine, transmission, and emissions equipment. We use the VIN to load the exact GM-certified software for your vehicle, ensuring perfect compatibility and performance.
Is this a plug-and-play part?
Yes! Because we program the module to your VIN before shipping, it arrives ready to install. In most cases, you will not need a scan tool or a trip to the dealer. We provide instructions for a simple key-relearn procedure if your vehicle’s security system requires it.
Will this fix my check engine light?
If the check engine light is caused by an internal PCM failure (like codes P0601-P0606), then yes, this module will resolve the issue. However, you should always diagnose other potential causes, such as faulty sensors, before replacing the PCM.
Where is the PCM located on my 1999 Sierra 1500?
On the 1999-2000 GMC Sierra and Chevy Silverado 1500, the PCM is typically mounted in the engine bay on the driver’s side, near the battery. It’s a silver metal box with multiple large electrical connectors.
Do I need to send my old PCM back?
This purchase does not require a core return. You can keep your old module, though we always recommend recycling old electronics responsibly.