Restore Your Van’s Performance with a VIN-Programmed Powertrain Module
Is your Chevrolet Express or GM truck giving you headaches? If you’re dealing with a persistent check engine light, stalling, rough idling, or a no-start condition, the problem often points directly to a failing Powertrain Control Module (PCM). As the central computer of your vehicle, a faulty PCM can cause a cascade of frustrating and hard-to-diagnose issues. I’ve seen it countless times in my shop: a work van that’s losing money every day it’s off the road, all because of a failing computer. This isn’t just a part; it’s the solution to getting your reliable workhorse back in service.
This isn’t a generic, one-size-fits-all module from a salvage yard. We provide a top-quality Powertrain Control Module, part number 21811787, that is professionally programmed specifically for your vehicle. Simply provide us with your Vehicle Identification Number (VIN) at checkout, and our technicians will flash the module with the latest GM-authorized software updates. This ensures perfect communication between your engine, transmission, and other systems, often resolving issues that even the original factory software didn’t address. By ordering a pre-programmed 1999-2002 Express 1500 PCM, you skip the expensive trip to the dealership for programming, saving you time and hundreds of dollars.
From the Diagnostic Bay: The Case of the Intermittent Stall
A local contractor brought in his 2001 Savana 2500 van. The complaint was an intermittent stall at traffic lights, with no specific trouble codes other than a random P0300 (Random Misfire) that would pop up occasionally. He’d already replaced plugs, wires, and the fuel filter. After checking fuel pressure and finding no vacuum leaks, my attention turned to the PCM. On these older GM vans, heat soak and vibration are the biggest enemies of the electronics in the engine bay. We connected our diagnostic scanner and monitored the live data. We noticed the injector pulse width would suddenly drop out for a split second, causing the stall. It was a classic sign of internal PCM failure. We replaced it with one of our VIN-programmed modules, and the van has been running reliably for him ever since. This simple swap saved his business from costly downtime.
Is Your GM Truck or Van Showing These Signs?
A failing PCM can manifest in many ways. If you’re experiencing any of the following, it’s a strong indicator that your module needs replacement:
- ✔ Check Engine Light is on with codes like P0601, P0602, or P0606 (Internal Control Module Errors).
- ✔ The engine cranks but refuses to start.
- ✔ Unexplained stalling or rough, erratic idling.
- ✔ A noticeable drop in fuel efficiency.
- ✔ Harsh or incorrect automatic transmission shifting.
- ✔ The vehicle fails to pass an emissions test.
A Straightforward Guide to Installation
Installing your new 1999-2002 Express 1500 PCM is a job most DIYers can handle in under an hour with basic hand tools. Since we program it for you, there’s no need for special scanners.
- Safety First: Always disconnect the negative terminal from your vehicle’s battery before starting any electrical work.
- Locate the PCM: On Express and Savana vans, the PCM is typically found in the engine compartment on the driver’s side, near the rear. On pickups and SUVs like the Tahoe or S10, it’s usually on the driver’s or passenger’s side fender wall, sometimes under the battery tray.
- Disconnect the Old Module: Carefully unplug the electrical harness connectors. They have locking tabs that need to be released. Be gentle to avoid damaging the pins or clips.
- Swap the Modules: Unbolt the old PCM from its mounting bracket and set it aside. Mount your new, pre-programmed module in its place.
- Reconnect Everything: Plug the harness connectors firmly into the new PCM until they click into place. Reconnect the negative battery terminal.
- Final Steps: In some cases, a security relearn procedure or a Crankshaft Variation (CASE) relearn may be required. This can often be done without special tools and instructions are widely available online for your specific model.
Verified Vehicle Compatibility
This module is a direct replacement for part numbers 16263494, 16265035, 8162634940, and 21811787. It is guaranteed to fit the following models, but please verify your part number or contact us with your VIN to ensure a perfect match.
CHEVROLET 2500 PICKUP 00 Electronic Control Module; gasoline (LH front engine compartment)
EXPRESS 1500 VAN 00-02 Electronic Control Module; (LH rear engine compartment), ID 16263494
EXPRESS 1500 VAN 99 Electronic Control Module; (LH rear engine compartment), ID 16263494
EXPRESS 2500 VAN 99-02 Electronic Control Module; (LH rear engine compartment), gasoline, ID 16263494
EXPRESS 3500 VAN 99-02 Electronic Control Module; (LH rear engine compartment), gasoline, ID 16263494
SAVANA 1500 VAN 99-02 Electronic Control Module; (LH rear engine compartment), ID 16263494
SAVANA 2500 VAN 99-02 Electronic Control Module; (LH rear engine compartment), gasoline, ID 16263494
SAVANA 3500 VAN 99-02 Electronic Control Module; (LH rear engine compartment), gasoline, ID 16263494
ASTRO 99-01 Electronic Control Module; (LH front by battery), ID 16263494
SAFARI (GMC) 99-01 Electronic Control Module; (LH front by battery), ID 16263494
BLAZER S10/JIMMY S15 98-00 Electronic Control Module; (RH front engine compartment)
S10/S15/SONOMA 98-00 Electronic Control Module; 4.3L (RH front engine compartment)
ISUZU HOMBRE 98-00 Electronic Control Module; 4.3L (RH front engine compartment)
BRAVADA 98-00 Electronic Control Module; (RH front engine compartment)
ENVOY 98-00 Electronic Control Module; (RH front engine compartment)
CHEVROLET/GMC 1500/2500/3500 PICKUP 99 Electronic Control Module; gasoline, ID 16263494
CHEVROLET/GMC 2500/3500 PICKUP 00 Electronic Control Module; gasoline
SILVERADO/SIERRA 1500 PICKUP 99-00 Electronic Control Module; 6 cylinder (LH front under battery)
TAHOE/YUKON 99 Electronic Control Module; gasoline, ID 16263494
TAHOE/YUKON 00 Electronic Control Module; Classic style / Denali
SUBURBAN 1500/2500 99 Electronic Control Module; gasoline, ID 16263494
ESCALADE 99-00 Electronic Control Module; (LH front engine compartment)
Note: Some 1998 models require build date option ZN4. Please verify before ordering.
Frequently Asked Questions About Your New PCM
Why do you need my VIN?
Why do you need my VIN?
Your Vehicle Identification Number (VIN) allows us to program the Powertrain Control Module with the exact software and calibrations specific to your vehicle’s engine, transmission, and options. This ensures a seamless, plug-and-play installation and optimal performance, just like a new part from the dealer.
Will this fix my check engine light?
If the check engine light is caused by an internal failure of the existing PCM (common codes P0601-P0606), then yes, this module will resolve the issue. However, if the light is on due to a faulty sensor or other mechanical problem, that issue will need to be repaired separately.
Is this part difficult to install myself?
For most DIYers with basic tools, this is a very straightforward installation. The main steps are disconnecting the battery, unplugging the old module, swapping it with the new one, and reconnecting everything. Since we pre-program the unit, you avoid the most difficult step of using specialized computer equipment.
What if my original part number is slightly different?
This module is compatible with several part numbers, including 16263494 and 16265035. Manufacturers often supersede part numbers over time. As long as your vehicle is on our compatibility list, this module will function correctly once programmed to your VIN. If you’re unsure, just send us a message with your VIN and we’ll verify compatibility for you.