Restore Peak Performance to Your GM Workhorse
As a technician with over two decades of experience under the hood, I’ve seen firsthand how a failing Powertrain Control Module (PCM) can turn a reliable truck or van into a source of constant frustration. It’s the brain of your vehicle, and when it starts to falter, you get baffling symptoms that can lead you down a rabbit hole of expensive, unnecessary repairs. This isn’t just a replacement part; it’s a direct solution to get your vehicle running smoothly and dependably again.
This PCM, part number 16263494, is the definitive fix for a wide range of popular GM trucks and vans from the 1998-2002 era. What sets our service apart is that we handle the most critical step for you. Before this module ships, we program it with the latest GM software updates, precisely matched to your vehicle’s unique VIN. This means no expensive trips to the dealership for programming. It arrives at your door ready for a straightforward installation, saving you time, money, and headaches.
Is Your Van or Truck Acting Up?
A faulty PCM can manifest in numerous ways. If you’re experiencing any of the following, a failing computer is a very likely culprit. I’ve diagnosed these exact issues hundreds of times in my shop.
- ✔ Check Engine Light is on with codes like P0601 (Internal Control Module Memory Check Sum Error) or other processor faults.
- ✔ Unexplained engine stalling or rough idling.
- ✔ Harsh or erratic automatic transmission shifting.
- ✔ A sudden drop in fuel economy.
- ✔ The engine cranks but refuses to start (no-start condition).
- ✔ Failure to pass an emissions or smog test.
- ✔ Communication errors with scan tools (U-codes).
From the Diagnostic Bay
I remember a 2001 Express 3500 work van that came into my shop with a persistent, random misfire on cylinder 3. The owner had already replaced the spark plug, wire, distributor cap, and rotor. He even swapped the fuel injector. Nothing worked. The misfire would come and go, making it a nightmare to diagnose. After ruling everything else out, we hooked up an oscilloscope to the injector driver circuit at the PCM. Sure enough, the signal from the module was weak and inconsistent. A failing driver inside the original PCM was the root cause. We installed one of our VIN-programmed modules, performed the security relearn, and the van ran perfectly. It’s a classic example of how a bad PCM can mimic other component failures.
Your Simple PCM Installation Guide
Replacing the PCM on these GM vehicles is a job most DIYers can handle with basic tools. The location varies slightly by model (check your vehicle’s specific location), but the process is generally the same.
- Safety First: Disconnect the negative terminal from your vehicle’s battery and secure it away from the post.
- Locate the PCM: On most Express/Savana vans, it’s in the LH rear of the engine compartment. On pickups and SUVs, it’s often on the LH side, sometimes under the battery tray.
- Disconnect the Connectors: Carefully unclip and remove all wiring harness connectors from the old PCM. These connectors have locking tabs; be gentle to avoid breaking them.
- Remove the Old Module: Unbolt the PCM from its mounting bracket and remove it from the vehicle.
- Install the New Module: Mount your new, pre-programmed PCM onto the bracket and securely re-fasten the bolts.
- Reconnect Everything: Firmly plug the wiring harness connectors back into the new PCM until they click into place. Reconnect the negative battery terminal.
- Perform Security Relearn (If Necessary): On many of these vehicles, you will need to perform a security relearn procedure to sync the new PCM with your vehicle’s anti-theft system. This typically involves turning the key to the ‘ON’ position for 10-15 minutes, then ‘OFF’, and repeating two more times. Your vehicle will not start until this is completed.
Verified Fitment For These GM Models
This module is a direct replacement for service number 16263494 and is also compatible with 16265035, 8162634940, 218-11787, and 21811787. Please confirm your part number or contact us with your VIN. It fits a wide array of vehicles, including:
- ✔ 1999-2002 Chevrolet Express & GMC Savana Vans (1500, 2500, 3500 Gasoline)
- ✔ 1999-2000 Chevrolet & GMC C/K Pickups (1500, 2500, 3500 Gasoline)
- ✔ 1999-2000 Chevrolet Silverado & GMC Sierra 1500 (4.3L V6)
- ✔ 1999-2000 Chevrolet Tahoe & GMC Yukon (Classic Body Style)
- ✔ 1999-2000 Cadillac Escalade
- ✔ 1998-2000 Chevrolet S10, GMC Sonoma, Isuzu Hombre (4.3L)
- ✔ 1998-2000 Chevrolet Blazer, GMC Jimmy, Oldsmobile Bravada
- ✔ 1999-2001 Chevrolet Astro & GMC Safari Vans
- …and more. Please see the detailed fitment list for specific options and years.
Frequently Asked Questions
Do I need to send you my VIN?
Yes, providing your Vehicle Identification Number (VIN) is mandatory. We use your VIN to program the module with the correct, latest software from GM for your specific vehicle configuration. This ensures compatibility and proper function right out of the box.
Is this a plug-and-play part?
Almost. Because we pre-program it to your VIN, you will not need a dealer-level scan tool for software flashing. However, you will likely need to perform a simple security relearn procedure (often called a Passlock or VATS relearn) which can be done without any special tools. Instructions are readily available online or in service manuals.
Will this fix my check engine light?
If the check engine light is caused by an internal failure of the original PCM (like code P0601), then yes, this will be the correct fix. It’s crucial to properly diagnose your vehicle first to ensure the PCM is the source of the problem and not a faulty sensor or wire.
What is the difference between an ECM and a PCM?
ECM stands for Engine Control Module, while PCM stands for Powertrain Control Module. In modern vehicles like these, the term PCM is more accurate as the module controls both the engine and the transmission functions. The terms are often used interchangeably.
Is there a core charge for my old module?
This listing does not require a core return, so there is no core charge. You can keep or dispose of your old module.