Restore Peak Performance to Your GM Truck or Van
Is your Chevrolet Express, GMC Savana, Tahoe, or Suburban running rough, stalling, or refusing to start? A failing Powertrain Control Module (PCM) is often the culprit behind these frustrating and complex issues. This vital component is the central brain of your vehicle, managing everything from fuel injection and spark timing to transmission shifting and emissions control. When it fails, the entire system can become unreliable. This replacement PCM, part number 09355699, is the definitive solution to get your trusted GM vehicle back on the road with confidence.
From the Diagnostic Bay
I once had a ’99 Suburban towed in with a classic intermittent no-start condition. It would run fine for days, then suddenly refuse to fire up. The owner had already replaced the fuel pump and ignition coil. After hours of chasing wires, I found the PCM would intermittently lose its 5-volt reference signal, shutting everything down. Swapping in a correctly programmed PCM like this one solved the problem instantly. These older GM units can develop internal connection failures that are impossible to see but cause the most maddening, intermittent symptoms.
Common Symptoms of a Failing PCM
- ✔ Check Engine Light is on with various communication or sensor codes.
- ✔ Engine stalls unexpectedly or struggles to stay running.
- ✔ Rough idling or misfiring that isn’t solved by new plugs and wires.
- ✔ Harsh or erratic automatic transmission shifting.
- ✔ A complete no-start condition where the engine cranks but won’t fire.
- ✔ Noticeable decrease in fuel economy.
- ✔ Failure to pass an emissions test.
The Right Solution: A VIN-Programmed 1998-1999 Express PCM
Finding a new PCM for these classic trucks is nearly impossible, and a generic one from a parts store won’t work without expensive dealer programming. This unit offers the perfect balance of reliability and convenience. It is a genuine, used OEM computer sourced from a salvaged vehicle, ensuring perfect factory fit and function. More importantly, we professionally program it using your vehicle’s specific Vehicle Identification Number (VIN) before it ships. This flashing process installs the latest GM-certified software updates, which can resolve factory bugs and improve overall vehicle operation. This means you receive a part that is truly plug-and-play, ready for installation right out of the box.
Installation and Security Relearn
Physically replacing the PCM is straightforward. It’s typically located in the engine bay and held in by a few bolts with three large electrical connectors. Once the new module is installed, you will need to perform a simple security relearn procedure to sync the new computer with your vehicle’s anti-theft system. This does not require any special tools and can be done in your driveway.
Standard Security Relearn Procedure:
- Insert the key and turn it to the “ON” position (do not start the engine).
- Observe the “Security” or lock symbol light on the dash. It will turn on and then go out after about 10-15 minutes.
- Once the light turns off, turn the key to the “OFF” position for 10 seconds.
- Repeat steps 1-3 two more times for a total of three cycles.
- After the third cycle, the vehicle will have learned the new PCM, and you can start the engine.
By providing us with your VIN at checkout, you ensure this 1998-1999 Express PCM arrives ready to restore your vehicle’s original functionality and reliability.
Frequently Asked Questions
Do I need to have this computer programmed?
No. We handle all the programming for you before we ship the part. Simply provide your vehicle’s VIN during or after checkout, and we will flash the module with the correct software for your specific vehicle.
Is this a new part?
This is a high-quality, tested, and fully functional used OEM part. It has been sourced from a salvaged vehicle and is guaranteed to work correctly once programmed and installed.
Where is the PCM located on my vehicle?
On most compatible models like the Express/Savana vans, Tahoe, Yukon, and pickups, the PCM is located in the engine compartment, typically on the driver’s side near the firewall or fender.
Will this fix my transmission problems?
It can. The PCM controls both engine and transmission functions. If your vehicle is experiencing erratic shifting, failure to shift, or transmission-related error codes, a faulty PCM could be the cause.
What if my part number is slightly different?
This PCM, service number 09355699, is a direct replacement for several other part numbers including 16266645, 16250279, and 9366810. As long as your vehicle is listed in the compatibility chart, this module will function correctly once programmed to your VIN.
What information do you need from me?
After you complete your purchase, we will need the 17-digit Vehicle Identification Number (VIN) from your vehicle. This is typically found on the driver’s side dashboard (visible through the windshield) or on the door jamb sticker.