Programmed 1998 Envoy Powertrain Control Module | 09355699 PCM

Restore Your Envoy’s Performance and Reliability

Is your 1998 GMC Envoy or another GM truck from that era giving you headaches? Unexplained stalling, a persistent check engine light, erratic shifting, or a frustrating no-start condition can often be traced back to a failing Powertrain Control Module (PCM). As the brain of your vehicle, when the PCM falters, everything from fuel economy to engine timing is affected. I’ve spent over 20 years in the garage, and I’ve seen countless drivers replace part after part, only to find the root cause was the computer all along. This isn’t just a replacement part; it’s a direct solution to get your dependable GM vehicle running smoothly again.

This module is the definitive fix for those nagging electronic issues. We take the guesswork and high dealership costs out of the equation. By providing us with your vehicle’s VIN at checkout, you receive a PCM that is professionally flashed with the latest official GM software updates. This ensures it communicates perfectly with your engine, transmission, and all related systems, just as it did the day it left the factory. A properly functioning 1998 Envoy Powertrain Control Module is critical for passing emissions tests and restoring the drivability you depend on.

Is Your Vehicle Showing These Symptoms?

• ✔ Check Engine Light is on with codes like P0601, P0605, or other communication errors.
• ✔ The engine cranks but refuses to start.
• ✔ Unexplained stalling or rough idling, especially when warm.
• ✔ Noticeable decrease in fuel mileage.
• ✔ Harsh or erratic automatic transmission shifting.
• ✔ Failure to pass state emissions testing.

A Straightforward Guide to Your PCM Installation

Replacing the PCM on these vehicles is a job most DIYers can handle with basic tools. Here’s a general guide to get you started:

1. Safety First: Always disconnect the negative terminal from your vehicle’s battery before starting any electrical work.
2. Locate the PCM: On the 1998 Envoy and similar S-series trucks, the PCM is typically found in the engine compartment on the right-hand (passenger) side, often near the firewall or inner fender. On full-size trucks and vans, it’s usually on the left-hand (driver) side.
3. Disconnect the Connectors: Carefully unclip and remove the electrical harness connectors from the old module. These connectors have locking tabs that need to be released. Avoid pulling on the wires themselves.
4. Remove the Old Module: Unbolt the PCM from its mounting bracket. There are typically two or three bolts holding it in place.
5. Install the New Module: Mount your new, pre-programmed PCM onto the bracket and securely fasten the bolts.
6. Reconnect Everything: Plug the harness connectors firmly into the new module until they click into place. Reconnect the negative battery terminal.
7. Perform Security Relearn: Your vehicle may require a simple security relearn procedure (often called VATS or Passlock) to recognize the new PCM. This usually involves turning the key to the ‘ON’ position for 10-15 minutes. We include instructions for this easy final step!

Verified Vehicle Compatibility List

This module is a direct replacement for part numbers 16250279, 09366810, and 09355699. Please match your part number or vehicle from the list below to ensure compatibility. This unit fits a wide range of GM vehicles:

• Astro / Safari (GMC): 1998-1999
• Blazer S10 / Jimmy S15: 1998 (w/o build date opt ZN4)
• Bravada: 1998 (w/o build date opt ZN4)
• Cadillac Escalade: 1999
• Chevrolet/GMC 1500, 2500, 3500 Pickups: 1998-1999 (Gasoline engines)
• Chevrolet/GMC Suburban 1500, 2500: 1998-1999 (Gasoline engines)
• Envoy: 1998 (w/o build date opt ZN4)
• Express / Savana 1500, 2500, 3500 Vans: 1998 (Gasoline engines)
• Isuzu Hombre: 1998 (4.3L, w/o extended build date opt ZN4)
• S10 / S15 / Sonoma: 1998 (4.3L, w/o build date opt ZN4)
• Tahoe / Yukon: 1998-1999 (Gasoline engines)