Is Your GM Truck or Van Running Rough? It Might Be the Brains of the Operation.
If you’re dealing with a no-start condition, a persistent check engine light, erratic shifting, or poor fuel economy in your late ’90s GM vehicle, the problem often points to a failing Powertrain Control Module (PCM). As a mechanic with over 20 years of diagnostic experience, I’ve seen countless cases where owners chase down sensors and wiring issues, only to find the root cause was the engine computer itself. The PCM is the central command center, and when its internal circuits fail, it can create a cascade of frustrating and hard-to-diagnose symptoms.
From the Shop Floor: A Real-World Diagnosis
“A customer’s ’99 Chevy C1500 came in last week with a dead misfire on cylinder 3 that wouldn’t go away. We checked the plug, wire, cap, and even swapped injectors, but the problem persisted. A quick check with a noid light showed the injector wasn’t getting a pulse. Instead of a wiring nightmare, my experience pointed me to the PCM. We scoped the injector driver circuit and confirmed it was dead. Swapping in a programmed PCM like this one had the truck running perfectly in under 15 minutes. It’s a fix I’ve performed hundreds of times on these reliable but aging vehicles.”
The Smart Solution: A Pre-Programmed 1998 Envoy PCM
Forget the dealership hassle and high costs. This is a genuine, used OEM Powertrain Control Module, part number 09355699, that has been meticulously tested and is ready for installation. The real value here is our professional programming service. Before we ship it, we flash the module with the latest GM-certified software updates and program it specifically to your vehicle’s VIN. This ensures all systems communicate correctly, from the engine and transmission to the anti-theft system.
- ✔ VIN Programmed for You: We handle the complex programming so you don’t have to. Just provide your VIN at checkout.
- ✔ Latest GM Software: Loaded with the most current updates to improve performance and efficiency over the original software.
- ✔ Direct-Fit Replacement: A guaranteed fit for a wide range of GM trucks, vans, and SUVs from 1998-1999. Also replaces part numbers 16266645, 16250279, 16258815, and 09366810.
- ✔ Cost-Effective Repair: Get the reliability of an OEM part without the new-part price tag.
- ✔ No Dealer Visit Needed: This module is shipped ready to install, saving you time and money on dealership programming fees.
Easy Installation to Get You Back on the Road
Installing this PCM is a straightforward job for a DIYer with basic tools. While specific locations vary slightly, you can generally get this done in under an hour.
- Safety First: Always disconnect the negative battery terminal before working on any electronic components.
- Locate the PCM: On most of these vehicles (like the Tahoe, Suburban, and pickups), you’ll find it in the engine compartment, typically on the driver’s side fender. On vans like the Express and Savana, it’s often in the LH rear engine compartment.
- Disconnect Connectors: Carefully unclip and swing the locking levers on the electrical harnesses to release them from the module.
- Remove the Old Unit: Unbolt the PCM from its mounting bracket and remove it from the vehicle.
- Install the New PCM: Bolt your new, pre-programmed module into place, reconnect the harnesses, and ensure the locking levers click securely.
- Final Steps: Reconnect the negative battery terminal. In many cases, the vehicle will start and run immediately. Some models may require a simple security relearn procedure, which can often be completed without special tools.
Will This Fit My Vehicle?
This Electronic Control Module is a direct replacement for units with service number 09355699. It fits a massive range of 1998 and 1999 General Motors vehicles, including the Chevrolet and GMC C/K 1500, 2500, and 3500 pickups, Suburban, Tahoe, Yukon, Escalade, Express and Savana vans, as well as the S10/Sonoma, Blazer/Jimmy, Astro/Safari, Bravada, and Isuzu Hombre. The most critical step is to match your existing part number to ensure compatibility.