Restore Your Workhorse: The Reliable Fix for Your GM Van or Truck
As a technician with over two decades of experience, I’ve seen firsthand how a failing Powertrain Control Module (PCM) can bring a perfectly good work van or truck to a grinding halt. If your 1999-2002 Express 3500 Van is experiencing frustrating issues like stalling, poor fuel economy, or a persistent check engine light, the PCM is often the culprit. This isn’t just an inconvenience; it’s lost time and money. This replacement 1999-2002 Express 3500 PCM is the definitive solution, designed to restore your vehicle’s performance and reliability without the dealership hassle or price tag.
The biggest hurdle with PCM replacement has always been the programming. An unprogrammed module is just a metal box. We eliminate that problem completely. Before we ship this module to you, our certified technicians will program it with the latest GM software updates using your vehicle’s specific Vehicle Identification Number (VIN). This means it arrives at your door ready for a straightforward installation. You get a component that communicates flawlessly with your vehicle’s systems, just like the original, ensuring optimal engine performance and transmission function from the moment you turn the key.
A Technician’s Notebook: The Intermittent No-Start Nightmare
I remember a 2001 Savana 3500 that came into the shop on a tow truck. The owner was at his wit’s end. The van would run fine for weeks, then suddenly refuse to start. No crank, no communication with the scan tool. After it sat for a few hours, it would fire right up as if nothing happened. We checked batteries, starters, and grounds—all perfect. The intermittent nature pointed to electronics. On these specific GM platforms, the PCM is located in the engine bay where it’s exposed to intense heat cycles. Over 20 years, these cycles can cause microscopic cracks in the circuit board’s solder joints. When the module was hot, the connection for the main processor relay would fail, cutting power and communication. Once it cooled, the connection was restored. Swapping in a quality, pre-programmed PCM like this one solved the problem permanently. It’s a classic failure I’ve diagnosed dozens of times.
Is Your Vehicle Showing These Symptoms?
- ✔️ Unexplained Check Engine Light with codes like P0601 (Internal Control Module Memory Check Sum Error) or other communication faults.
- ✔️ The engine cranks but refuses to start.
- ✔️ Sudden stalling or rough idling, especially after the engine has warmed up.
- ✔️ Noticeable decrease in fuel efficiency.
- ✔️ Harsh or erratic automatic transmission shifting.
- ✔️ Communication issues where a scan tool cannot connect to the PCM.
- ✔️ Misfire codes that persist even after replacing plugs, wires, and coils.
A Straightforward Guide to Installation
- ✔ Safety First: Always disconnect the negative terminal from your vehicle’s battery before beginning any work on the electrical system.
- ✔ Locate the PCM: On most Express and Savana vans, the PCM is located in the engine compartment on the driver’s side, near the rear. On pickups and SUVs, it’s typically on the driver’s side fender well or near the battery.
- ✔ Disconnect Connectors: Carefully unplug the wiring harness connectors from the old module. These connectors have locking tabs that may need to be gently pried or squeezed to release. Inspect the connectors for any corrosion or damaged pins.
- ✔ Remove the Old Module: Unbolt the old PCM from its mounting bracket. It’s usually held in by a few bolts or nuts.
- ✔ Install the New Module: Mount your new, pre-programmed PCM onto the bracket and securely fasten it. Reconnect the wiring harnesses, ensuring they click firmly into place.
- ✔ Reconnect Battery: Reattach the negative battery terminal.
- ✔ Perform Security Relearn (If Needed): In many cases, you may need to perform a simple Passlock/VATS security relearn. Turn the key to the ‘ON’ position for 10-15 minutes, then ‘OFF’ for 10 seconds. Repeat this cycle three times. On the fourth try, the vehicle should start.
Verified Vehicle Compatibility
This module is a direct replacement for part numbers 16263494, 16265035, 8162634940, and 218-11787. It is guaranteed to fit the following vehicles. Please ensure your vehicle’s part number matches to confirm fitment.
GMC 1500/2500/3500 PICKUP 99-00 (gasoline), SAVANA 1500/2500/3500 VAN 99-02 (gasoline), SIERRA 1500 PICKUP 99-00 (6 cyl), SONOMA 98-00 (4.3L), JIMMY 98-00, SAFARI 99-01, YUKON 99-00 (incl. Denali)
CADILLAC ESCALADE 99-00
ISUZU HOMBRE 98-00 (4.3L)
OLDSMOBILE BRAVADA 98-00, ENVOY 98-00
Note: Some 1998 models require build date option ZN4. Please verify.
Frequently Asked Questions
Do I need to do anything after I buy this 1999-2002 Express 3500 PCM?
Yes. After your purchase, you must provide us with your vehicle’s 17-digit VIN. We cannot ship the module until we have programmed it specifically for your van or truck.
Is this a plug-and-play part?
Mostly, yes. Because we pre-program it with your VIN, it eliminates the need for a trip to the dealer for software flashing. However, on many of these GM vehicles, you will need to perform a simple 30-minute security relearn procedure with your key to sync the module to your vehicle’s anti-theft system.
Will this fix my check engine light?
If the check engine light is caused by an internal failure of the PCM (like code P0601), then yes, this will resolve the issue. However, you should always diagnose the codes first to ensure the problem isn’t a faulty sensor or wiring.
What is the difference between a PCM and an ECM?
The terms are often used interchangeably. ECM (Engine Control Module) typically just controls the engine. A PCM (Powertrain Control Module) controls both the engine and the automatic transmission. For these vehicles, PCM is the more accurate term.
Do you need my old part back?
This listing does not require a core return. You can keep or dispose of your old module.