Is Your GM Truck or Van Running Rough?
If you’re dealing with frustrating and unpredictable issues like a persistent check engine light, poor fuel economy, erratic shifting, or even a no-start condition, the problem might be the very brain of your vehicle: the Powertrain Control Module (PCM). For a wide range of GM vehicles from 1998 to 2002, this module is the central command unit responsible for engine performance and transmission function. When it fails, it can cause a cascade of problems that are often misdiagnosed, leading to wasted time and money on unnecessary sensor replacements.
This replacement Powertrain Control Module is the definitive solution to restore your vehicle’s reliability and performance. More than just a part, this is a complete service. We flash the module with the latest official GM software updates tailored specifically to your vehicle using the VIN you provide. This critical step ensures that the module communicates perfectly with all your vehicle’s systems, just as it did from the factory. You get a component that is ready for installation, saving you a costly trip to the dealership for programming.
From the Diagnostic Bay
I once had a 2001 Savana van come into the shop that had its owner at his wit’s end. He had replaced the throttle position sensor three times, the mass airflow sensor twice, and was about to replace the entire transmission based on another shop’s advice. The van would intermittently stall at lights and shift harshly from first to second. A quick scan showed a slew of communication error codes. Instead of chasing ghosts, we checked the power and ground signals to the PCM, which were solid. This pointed to an internal failure of the module itself. We installed a VIN-programmed PCM like this one, performed the quick security relearn, and the van ran perfectly. It’s a classic case of treating the disease, not just the symptoms.
Symptoms of a Failing Powertrain Control Module
- ✔ Persistent Check Engine Light (CEL) that won’t clear or returns immediately.
- ✔ Diagnostic trouble codes related to module communication errors (U-codes) or internal processor faults (P06xx codes).
- ✔ Unexplained drop in fuel efficiency.
- ✔ Harsh or erratic automatic transmission shifting.
- ✔ Engine stalling, stumbling, or misfiring for no apparent reason.
- ✔ The vehicle cranks but refuses to start.
- ✔ Failure to pass an emissions test.
The Core Function of Your 1999-2002 Express 3500 PCM
In your Chevrolet Express or GMC Savana, the 1999-2002 Express 3500 PCM is the master controller. It takes in data from dozens of sensors—like the crankshaft position, oxygen sensors, and vehicle speed—and uses this information to make thousands of calculations per second. It precisely controls fuel injection timing, ignition spark, transmission shift points, and emissions components. A failing module can disrupt any of these critical functions, leading to the symptoms you’re experiencing. By replacing it with a correctly programmed unit, you are restoring the central nervous system of your powertrain.
This module is a direct-fit replacement, designed to meet or exceed original equipment specifications. Once you provide us with your Vehicle Identification Number (VIN), our technicians will load the correct software for your specific engine, transmission, and emissions package. This ensures a seamless installation process. In most cases, a simple security relearn procedure (often called a VATS or Passlock relearn) is all that’s needed after installation, a process you can typically do yourself in your driveway with just the ignition key.
Compatible Part Numbers: 16263494, 16265035, 8162634940, 218-11787, 21811787
Frequently Asked Questions
Do I need to get this module programmed?
No. This module comes fully programmed to your vehicle’s specific VIN before we ship it. Simply provide your VIN during or after checkout, and we handle the rest. This makes it ready for installation right out of the box.
What is the difference between a PCM, ECM, and ECU?
The terms are often used interchangeably. ECM (Engine Control Module) typically controls only engine functions. A PCM (Powertrain Control Module) controls both the engine and the transmission. ECU (Electronic Control Unit) is a more generic term. For these GM vehicles, this part is a PCM as it manages both systems.
Will this fix my check engine light?
If the check engine light is caused by an internal fault within your existing PCM, then yes, this part will solve the problem. However, it’s crucial to ensure proper diagnosis has been performed, as the light can be triggered by many other faulty components like sensors or wiring.
Is a security relearn procedure required after installation?
Yes, in most cases, you will need to perform a security relearn procedure. This syncs the new module to your vehicle’s anti-theft system. It’s typically a simple process that involves cycling the ignition key and can be done without any special tools. We can provide instructions upon request.
Where do I find my vehicle’s VIN?
You can find your 17-digit VIN on the driver’s side of the dashboard (visible through the windshield), on the driver’s side door jamb sticker, or on your vehicle’s registration and insurance documents.