Is Your 1998 GMC Envoy Running Rough? Get the Right Fix, Fast.
If you’re dealing with a persistent check engine light, poor fuel economy, stalling, or erratic shifting in your GMC Envoy or a similar GM truck, a failing Powertrain Control Module (PCM) is often the culprit. I’ve seen it hundreds of times in my shop: drivers spend a fortune replacing sensors and parts, only to find the vehicle’s computer was the root cause all along. This isn’t just a replacement part; it’s a direct solution to restore your vehicle’s performance and reliability.
This is a genuine, road-tested used PCM that has been professionally programmed with the latest GM factory software updates specifically for your vehicle’s VIN. This critical step ensures that all parameters for your engine and transmission are set correctly, something a generic, non-programmed module from a junkyard can’t do.
Why Choose a VIN-Programmed Module?
- โ Guaranteed Compatibility: We flash the module with your vehicle’s unique VIN, ensuring it communicates perfectly with your specific engine, transmission, and options.
- โ Latest Software: Your PCM will arrive with the newest GM operational software, which often includes fixes for common drivability issues that were discovered after your truck left the factory.
- โ Cost-Effective Repair: Avoid the high costs and scheduling hassles of a dealership visit. This module is a budget-friendly, effective solution.
- โ Plug-and-Play Solution: Once you receive it, the module is ready for installation. No additional programming is required.
From the Shop Floor: A Real-World Diagnosis
“A customer’s ’98 GMC Jimmy S15 came in last week with what he was convinced was a failing transmissionโharsh shifts and intermittent refusal to shift out of first gear. He had already replaced the vehicle speed sensor. After a quick scan, I saw no transmission-specific codes, but there were some erratic data readings from the PCM. Instead of an expensive transmission rebuild, we swapped in a VIN-programmed PCM like this one. The shifting problems vanished instantly. It’s a classic case where the ‘brain’ causes symptoms that look like something else entirely.”
Simple Installation for Your 1998 Envoy PCM
Replacing the PCM is a straightforward job you can do in your own driveway. For the 1998 Envoy, it’s typically located in the right-front of the engine compartment.
- Safety First: Disconnect the negative terminal from your vehicle’s battery and wait 10-15 minutes for the system to fully discharge.
- Locate the PCM: Find the module in the engine bay. It’s a metal box with several large electrical connectors.
- Disconnect Connectors: Carefully unclip and remove all wiring harness connectors from the old PCM.
- Remove the Old Module: Unbolt the old PCM from its mounting bracket.
- Install the New Module: Bolt your new, programmed PCM into place.
- Reconnect Everything: Firmly plug all wiring connectors into the new module. Reconnect your battery terminal. The vehicle is now ready to start.
Expert Pro Tip Before You Install
Before plugging in your new PCM, take a moment to inspect the harness connectors. Look for any signs of corrosion (green or white powder) on the pins or moisture inside the connector housing. Use a small brush and electrical contact cleaner to gently clean the pins. A poor connection is the number one reason for a replacement module to fail prematurely or not work at all.
Fitment and Part Number Confirmation
This module is a direct replacement for several original equipment part numbers. Please verify your original part number is on this list to ensure compatibility.
Replaces Part Numbers: 09355699, 16266645, 9355699, 16250279, 16258815, 09366810, 9366810
This module is confirmed to fit the following vehicles (with ID 9355699):
- Astro / Safari (GMC): 1998
- Blazer S10 / Jimmy S15: 1998 (w/o build date opt ZN4)
- Bravada: 1998 (w/o build date opt ZN4)
- Cadillac Escalade: 1999
- Chevrolet / GMC C/K 1500, 2500, 3500 Pickup: 1998-1999 (Gasoline)
- Chevrolet / GMC Suburban 1500, 2500: 1998-1999 (Gasoline)
- Envoy: 1998 (w/o build date opt ZN4)
- Express / Savana 1500, 2500, 3500 Van: 1998-1999 (Gasoline)
- 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)
IMPORTANT: After purchase, please send us your vehicle’s 17-digit VIN. We cannot ship your order until we have this information to program the module.