Is Your GM Truck or Van Acting Up?
If your late 90s Chevrolet, GMC, or Cadillac is suffering from frustrating issues like intermittent stalling, harsh shifting, a persistent check engine light, or a complete no-start condition, a failing Powertrain Control Module (PCM) is often the culprit. As a mechanic with over two decades of experience under the hood, I’ve seen these exact symptoms on hundreds of these workhorse vehicles. The PCM is the brain of your engine and transmission, and when it starts to fail, it can cause a cascade of problems that are difficult to diagnose.
The Simple, Reliable Solution: A VIN-Programmed PCM
Forget expensive dealership visits and the hassle of finding a local shop with the right equipment. We offer a dependable, tested OEM PCM that comes ready for installation. This isn’t just a part in a box; it’s a complete solution. We use your vehicle’s Vehicle Identification Number (VIN) to flash the module with the latest, most stable software updates directly from GM. This ensures perfect compatibility and function, restoring your vehicle’s performance and reliability.
Expert Pro Tip: Check Your Grounds First!
Before you replace your PCM, take 10 minutes to check the main engine-to-chassis ground straps. On these GMT400 platform trucks and vans, the ground connection near the thermostat housing is notorious for corrosion. A poor ground can mimic PCM failure by causing erratic sensor readings and communication errors. Cleaning this connection with a wire brush until it’s bright and shiny has saved my customers hundreds of dollars in unnecessary diagnostics.
Common Symptoms of a Failing GM PCM:
- โ Check Engine Light (CEL) is on with communication error codes (U-codes).
- โ Engine stalls unexpectedly or refuses to start.
- โ Rough or inconsistent engine idle.
- โ Automatic transmission shifts harshly, late, or not at all.
- โ Noticeable decrease in fuel economy.
- โ The anti-theft or security light stays on, preventing the engine from starting.
Plug-and-Play Installation: No Dealer Visit Required
Installing your replacement 1998-1999 Chevrolet 3500 PCM is a straightforward job you can do in your own driveway. Because we program it to your VIN before shipping, it’s ready to go right out of the box. In most cases, you will not need to perform any additional security relearn procedures.
- Safety First: Disconnect the negative terminal from your vehicle’s battery.
- Locate the PCM: On most trucks and SUVs, it’s in the engine compartment on the driver’s side fender. On Express/Savana vans, it’s typically in the LH rear engine compartment.
- Disconnect Connectors: Carefully unclip the wiring harness connectors from the old PCM. Inspect the pins for any corrosion or damage.
- Remove Old Module: Unbolt the old PCM from its mounting bracket.
- Install New Module: Bolt the new, pre-programmed PCM into place and securely reconnect the wiring harnesses. You should hear a distinct click.
- Reconnect Battery: Reattach the negative battery terminal.
- Start Vehicle: Turn the key and let the engine idle for a few minutes as the system recalibrates. Your vehicle is ready to drive!
Guaranteed Compatibility
This module is a direct replacement for several service numbers. As long as your original module has one of the following part numbers, this unit will work for your vehicle once programmed:
Part Numbers: 09355699, 16266645, 9355699, 16250279, 16258815, 09366810
This unit fits a massive range of 1998-1999 GM vehicles, including the Chevrolet/GMC 1500, 2500, and 3500 pickups, Suburban, Tahoe, Yukon, Escalade, Express and Savana vans, Astro and Safari vans, and more. The key is matching the service ID number, which is typically 09355699 for this family of computers.