Restore Peak Performance to Your GM Truck or Van
Is your Chevrolet Express, GMC Savana, or S10 Blazer running rough, shifting erratically, or refusing to start? A failing Powertrain Control Module (PCM) is often the culprit behind these frustrating and complex issues. As the central computer of your vehicle, the PCM manages everything from fuel injection and ignition timing to transmission shift points and emissions controls. When it fails, the entire vehicle’s performance suffers. This replacement Powertrain Control Module, compatible with part number 21811787 and 16263494, is the definitive solution to get your reliable GM vehicle back on the road.
From the Diagnostic Bay
I remember a customer with a 2001 Savana 2500 work van. He’d spent a fortune replacing the transmission because it was shifting hard and erratically. The new transmission did the exact same thing. He was at his wit’s end. After hooking up our scanner, we saw that the PCM was sending faulty signals to the transmission solenoids. It wasn’t a mechanical problem at all; it was electronic. We installed one of these VIN-programmed PCMs, performed the security relearn, and the van shifted like it just rolled off the factory line. It’s a classic case of the vehicle’s ‘brain’ causing problems that look like something else entirely.
Symptoms of a Failing Powertrain Control Module
- ✔ Check Engine Light is illuminated with various trouble codes.
- ✔ Harsh or unpredictable automatic transmission shifting.
- ✔ Engine stalling, stumbling, or misfiring for no apparent reason.
- ✔ A complete no-start condition where the engine cranks but won’t fire up.
- ✔ Poor fuel economy and a noticeable loss of power.
- ✔ Communication errors with diagnostic scan tools.
- ✔ Intermittent issues that are difficult to replicate.
The Plug-and-Play Solution: Your 1999-2002 Express PCM
Don’t waste time and money at the dealership. We simplify the repair process by programming this module specifically for your vehicle before it ships. Simply provide us with your vehicle’s 17-digit VIN (Vehicle Identification Number) during checkout, and our technicians will flash the unit with the latest, most stable GM-certified software for your exact configuration. This ensures that all engine and transmission parameters are correct, restoring the original performance and efficiency of your vehicle. This is not a generic, one-size-fits-all part; it’s a component prepared specifically for your truck or van.
This module is a direct-fit replacement for a wide range of GM vehicles from the late 1990s and early 2000s, including the Chevrolet Silverado, GMC Sierra, Tahoe, Yukon, and many more. Please verify your original part number or consult the detailed fitment list to ensure compatibility.
Frequently Asked Questions
Do I need to program this PCM?
No. We handle all the programming for you before shipment. Just provide your vehicle’s VIN at checkout, and the module will arrive ready for installation and the security relearn procedure.
What is a security relearn procedure?
Most GM vehicles of this era use a Passlock or Passkey anti-theft system. After installing the new PCM, you will need to perform a simple relearn procedure so the module recognizes your key. This typically involves turning the key to the ‘ON’ position for 10-15 minutes, then off, and repeating two more times. Instructions are readily available online for your specific model.
Where is the PCM located on my vehicle?
Location varies by model. On Express and Savana vans, it’s typically in the LH rear of the engine compartment. On pickups like the Silverado or S10, it can be on the LH or RH side of the engine compartment, sometimes near or under the battery tray.
How do I find my original part number?
Your original part number is printed on a sticker on the module itself. Common numbers this part replaces are 16263494 and 16265035. Matching this number is the best way to ensure compatibility.
What happens if I install it without the security relearn?
The vehicle will not start. The security system will disable the fuel injectors, believing the vehicle is being stolen. The relearn procedure is a mandatory step.