Is Your GM Truck or SUV Acting Up? Get a Reliable, Programmed Solution.
As a technician with over two decades of experience, I’ve seen countless GM vehicles from the late ’90s roll into the bay with baffling electrical issues. From a 1998 GMC Envoy that won’t start to a ’99 Suburban that stalls randomly at traffic lights, the root cause is often a failing Powertrain Control Module (PCM). This isn’t just an inconvenience; it’s a critical component failure that can leave you stranded. If your trusty truck or van is on the fritz, you’ve found the straightforward, cost-effective fix.
This is a genuine, tested, used GM PCM, part number 9355699, sourced from a salvaged vehicle. The real value here is that we flash it with the latest GM software updates specifically for your vehicle. Simply provide your Vehicle Identification Number (VIN) after purchase, and we handle the programming before it ships. This means no expensive trips to the dealership for programming. You get a part that’s ready to install right out of the box, restoring your vehicle’s performance and reliability.
A Technician’s Notebook: The Intermittent Stall Case
I remember a 1999 Chevy Suburban that came in with a frustrating problem: it would die intermittently at idle, with no specific pattern. The owner had already replaced the fuel pump and ignition components. After hooking up my scan tool and monitoring live data, I noticed the fuel trim and injector pulse width would suddenly go erratic just before a stall. There were no hard codes, just a history of a P0601 (Internal Control Module Memory Check Sum Error). This pointed directly to a failing PCM. We installed a pre-programmed module just like this one, and the truck ran perfectly. It’s a classic failure mode for these units, where internal board components break down over time, causing unpredictable behavior.
Is Your Vehicle Showing These Telltale Signs?
A failing PCM can manifest in numerous ways. If you’re experiencing any of the following, this module is likely the solution you need. This is especially true if you’ve scanned for codes and found P0601, P0602, or P0606.
- ✔ Engine stalling or shutting off while driving
- ✔ No-start or hard-starting conditions
- ✔ Persistent Check Engine Light
- ✔ Poor fuel economy and rough idling
- ✔ Harsh or incorrect automatic transmission shifting
- ✔ Communication errors with diagnostic scan tools
A Straightforward Guide to Installation
Installing your programmed 1998 Envoy PCM is a job most DIYers can handle in their own driveway. Follow these steps for a smooth installation.
- Safety First: Always disconnect the negative terminal from your vehicle’s battery before starting any electrical work.
- Locate the PCM: On most of these GM trucks, vans, and SUVs, the PCM is located in the engine compartment, often on the driver’s side fender well or near the battery. Refer to your vehicle’s service manual for the exact location.
- Disconnect the Connectors: Carefully unlatch and remove the electrical harness connectors from the old PCM. These connectors have locking tabs that need to be released before they can be pulled off. Avoid forcing them.
- Remove the Old Module: Unbolt the old PCM from its mounting bracket. There are typically two or three bolts holding it in place.
- Install the New Module: Mount your new, pre-programmed PCM onto the bracket and secure it with the bolts.
- Reconnect Everything: Firmly plug the electrical connectors into the new PCM until they click and lock into place. Reconnect the negative battery terminal.
- Perform Security Relearn (If Necessary): In some cases, a security relearn procedure may be required for the vehicle to start. This typically involves turning the key to the ‘ON’ position for 10-15 minutes, then off, and repeating two more times. This allows the new PCM to sync with your vehicle’s anti-theft system.
Verified Vehicle Compatibility
This module, identified by part number 9355699, is a direct replacement for a wide range of GM vehicles. Please match your original part number or verify your vehicle is on the list below. This part is compatible with service numbers 09355699, 16266645, 16250279, 16258815, 09366810, and 9366810.
CHEVROLET 2500/3500 PICKUP 98-99 (Gasoline)
EXPRESS/SAVANA VAN 1500/2500/3500 98-99 (Gasoline)
GMC 1500 PICKUP 98-99 (5.0L, 5.7L)
GMC 2500/3500 PICKUP 98-99 (Gasoline)
CADILLAC ESCALADE 99
CHEVROLET TAHOE 98-99 (Gasoline)
GMC YUKON 98-99
CHEVROLET SUBURBAN 1500/2500 98-99 (Gasoline)
ASTRO / SAFARI VAN 98
BLAZER S10 / JIMMY S15 98 (w/o build date opt ZN4)
S10 / S15 / SONOMA 98 (4.3L, w/o build date opt ZN4)
OLDSMOBILE BRAVADA 98 (w/o build date opt ZN4)
GMC ENVOY 98 (w/o build date opt ZN4)
ISUZU HOMBRE 98 (4.3L, w/o extended build date opt ZN4)
Frequently Asked Questions
Do I need to do any programming myself?
No. We program the module to your vehicle’s VIN before we ship it. It arrives ready for installation. In some cases, a simple key-cycle security relearn procedure is needed, which requires no special tools.
Is this a new part?
No, this is a high-quality, tested, and guaranteed used part sourced from a salvaged vehicle. This allows us to provide a reliable, factory component at an affordable price.
How do I provide my VIN?
After completing your purchase, you will receive instructions on how to send us your 17-digit Vehicle Identification Number (VIN). We cannot ship your order until we receive this information.
Will this fix my specific problem?
This PCM is a direct solution for issues caused by a faulty engine computer, such as those listed in the symptoms section. While it solves the most common problems, we always recommend a proper diagnosis by a qualified mechanic to ensure you are replacing the correct part.
What if my part number is slightly different?
This module replaces several part numbers, including 16266645, 16250279, 16258815, 09366810, and 9366810. As long as your vehicle is on the compatibility list and your original part number is one of these, this module will work.