Is Your GM Truck or Van Plagued with Frustrating Electrical Gremlins?
If you’re dealing with a no-start condition, erratic shifting, a persistent check engine light with a cluster of unrelated codes, or stalling on your 1998-1999 GM vehicle, a failing Powertrain Control Module (PCM) is often the culprit. Over my 20+ years in the shop, I’ve seen countless GMT400 and GMT600 platform vehicles—from workhorse Savana vans to family Suburbans—sidelined by a faulty computer. The symptoms can be maddening, often leading owners to replace perfectly good sensors and parts before identifying the true source of the problem.
This isn’t just a replacement part; it’s a direct solution. We are offering a reliable, tested, used OEM Powertrain Control Module with service number 09355699. The most critical part of this service is that we flash the module with the latest official GM software updates, specifically programmed to your vehicle’s VIN before it ships. This eliminates the need for expensive dealer programming and ensures seamless communication with your vehicle’s other systems.
Expert Pro Tip: Check Your Grounds First!
Before you replace your PCM, do a quick visual inspection of the main ground straps. On these GM trucks and vans, there’s typically a ground from the engine block to the firewall and another to the frame. Over time, they can corrode or break. A bad ground can cause voltage issues that mimic PCM failure, throwing all sorts of strange codes. Cleaning the contact points with a wire brush is a 10-minute check that has saved my customers hundreds of dollars in diagnostics.
Symptoms of a Failing 1998-1999 Savana 3500 PCM
A failing engine computer can manifest in numerous ways. If your vehicle is experiencing any of the following, this module is the likely solution:
- ✔ Engine cranks but will not start (no-start condition)
- ✔ Harsh or erratic automatic transmission shifting
- ✔ Misfire codes on multiple cylinders
- ✔ Communication loss codes with other modules (U-codes)
- ✔ Vehicle stalls intermittently for no apparent reason
- ✔ Poor fuel economy and overall performance
- ✔ Check Engine Light (CEL) is on with codes pointing to multiple failed sensors
Plug-and-Play Installation: No Dealer Visit Required
Because we program the module to your VIN, the complex and costly security relearn procedures are often bypassed, making for a straightforward installation you can do at home. While specific locations vary slightly by model, the process is generally the same.
- Safety First: Disconnect the negative terminal from your vehicle’s battery.
- Locate the PCM: On most models like the Savana, Express, Tahoe, and pickups, the PCM is located in the engine compartment, typically on the driver’s side near the fender or firewall.
- Disconnect the Connectors: Carefully unclip and remove the wiring harness connectors from the old module. Inspect the pins for any corrosion or damage.
- Swap the Modules: Unbolt the old PCM and secure the replacement module in its place.
- Reconnect Everything: Firmly plug the wiring harnesses into the new PCM until they click. Reconnect the negative battery terminal.
- Final Check: Turn the key to the ‘On’ position for 10-15 seconds before starting the engine. This allows the systems to initialize. Start your vehicle and enjoy restored performance!
This unit is a direct replacement for part numbers 09355699, 16266645, 16250279, 16258815, and 09366810, and fits a wide range of GM trucks, vans, and SUVs from 1998-1999. By providing your VIN, you guarantee you receive a part that is correctly configured for your vehicle’s specific options and systems, right out of the box.