Get Your Workhorse Back on the Job with a Reliable, Programmed PCM
As a technician with over two decades of experience, I know that when your Chevy Express or GMC Savana van is down, your business is down. Intermittent stalling, a persistent check engine light, or erratic transmission shifting isn’t just an annoyance—it’s a critical failure that costs you time and money. The Powertrain Control Module (PCM), the electronic brain of your vehicle, is often the culprit. This isn’t just a replacement part; it’s a complete, plug-and-play solution. We take your vehicle’s VIN and flash this module with the latest, most stable GM factory software before it ever leaves our facility. This ensures it communicates perfectly with your engine and transmission, restoring the performance and reliability you depend on.
From the Diagnostic Bay: The Case of the Wandering Work Van
I remember a 2001 Express 3500 that came into my shop a few years back. The owner was frustrated. He’d replaced sensors and thrown parts at it, but it would still randomly stall at traffic lights and hesitate under acceleration. No consistent codes, just pure frustration. After hooking up my scan tool and monitoring live data, I noticed the fuel trim and ignition timing data would drop out intermittently. This pointed directly to a processing fault inside the PCM. The internal circuit boards on these modules can develop micro-fractures from years of heat cycles and vibration. We installed a VIN-programmed PCM just like this one, performed the security relearn, and the van ran like it just rolled off the factory line. It’s a fix I’ve performed hundreds of times, and it’s almost always the definitive solution for these specific symptoms.
Is Your GM Van or Truck Showing These Signs?
A failing PCM can cause a wide range of confusing issues. If you’re experiencing any of the following, this module is the likely solution your vehicle needs. Look out for:
- âś” Check Engine Light is on with codes like P0601 (Internal Control Module Memory Check Sum Error) or P0606 (PCM Processor Fault).
- âś” The engine cranks but refuses to start.
- âś” Unexplained stalling or rough idling, especially when the engine is warm.
- âś” Harsh or erratic automatic transmission shifting.
- âś” A noticeable decrease in fuel economy.
- âś” Communication errors with your scan tool.
- âś” The anti-theft or security light stays on, preventing the engine from starting.
Your Straightforward Installation Guide
Replacing the PCM in these GM vehicles is a job most DIYers can handle in their own driveway. Our pre-programming service eliminates the most difficult step. Follow this process for a smooth installation:
- Safety First: Always disconnect the negative terminal from your vehicle’s battery and secure it away from the post to prevent accidental contact.
- Locate the PCM: On most Express/Savana vans, the PCM is located in the engine compartment on the driver’s side, near the rear. On pickups and SUVs, it’s often on the driver’s side fenderwell or near the battery.
- Disconnect the Harnesses: Carefully release the locking tabs on the electrical connectors and pull them straight out from the module. Avoid pulling on the wires themselves. There are typically multiple color-coded connectors.
- Remove the Old Module: Unbolt the PCM from its mounting bracket. Keep the hardware, as you may need to reuse it.
- Install the New Module: Mount your new, pre-programmed PCM and securely reconnect the electrical harnesses. You’ll hear a click as they lock into place.
- Reconnect the Battery: Re-attach the negative battery terminal and tighten it securely.
- Perform Security Relearn (If Necessary): Your vehicle may require a security relearn procedure to recognize the new PCM. This typically involves turning the key to the ‘ON’ position for 10-15 minutes, then ‘OFF’, and repeating two more times. This allows the Body Control Module to sync with the new PCM. After this, the vehicle should start and run correctly.
By choosing this pre-flashed 1999-2002 Express 3500 PCM, you are not only getting a quality part but also saving yourself the significant cost and inconvenience of having a dealership or specialized shop perform the programming.
Verified Compatibility for Your Vehicle
This module is a direct replacement for part numbers 16263494, 16265035, 8162634940, and 21811787. It fits a wide range of GM trucks, vans, and SUVs. Please verify your vehicle is on this list:
- Chevrolet Express / GMC Savana Vans (1500, 2500, 3500): 1999, 2000, 2001, 2002 (Gasoline engines)
- Chevrolet / GMC Pickups (1500, 2500, 3500): 1999, 2000 (Gasoline engines)
- Chevrolet Silverado / GMC Sierra 1500: 1999-2000 (4.3L V6)
- Chevrolet S10 / GMC Sonoma / Isuzu Hombre: 1998, 1999, 2000 (4.3L V6)
- Chevrolet Blazer / GMC Jimmy / Oldsmobile Bravada / GMC Envoy: 1998, 1999, 2000
- Chevrolet Astro / GMC Safari: 1999, 2000, 2001
- Chevrolet Tahoe / GMC Yukon: 1999, 2000 (including Denali & Classic styles)
- Cadillac Escalade: 1999, 2000
- Chevrolet / GMC Suburban (1500, 2500): 1999
Note: For some 1998 models, fitment depends on the build date option ZN4. For other models, the ID number 16263494 must match. Always confirm your part number or contact us with your VIN if you are unsure.
Frequently Asked Questions
Do I need to do anything after I install this PCM?
In most cases, you will need to perform a simple security relearn procedure, also known as a Passlock or VATS relearn. This can be done without any special tools and typically takes about 30 minutes. We include instructions for this process with your order.
Why do you need my VIN?
Your Vehicle Identification Number (VIN) is essential. It allows us to program the PCM with the exact software calibration and updates specific to your vehicle’s engine, transmission, and options. This ensures seamless communication and optimal performance, eliminating the need for a trip to the dealer.
Is this a new or used part?
This is a high-quality, tested replacement part that has been professionally prepared and programmed for your vehicle. We ensure every module meets strict performance standards before being shipped.
Will this fix my transmission shifting problems?
Yes, in many cases it will. The PCM controls transmission line pressure and shift points. If the module is failing, it can cause hard shifting, slipping, or delayed engagement. A properly functioning 1999-2002 Express 3500 PCM will restore correct transmission operation.
How do I find my original part number?
Your original part number is printed on a sticker on the PCM itself. You may need to unbolt the module to see it clearly. The most common compatible number is 16263494.