Restore Your Van’s Performance and Reliability
Is your 1998-1999 GMC Savana 3500 van running rough, stalling unexpectedly, or showing a persistent check engine light? These are classic signs of a failing Powertrain Control Module (PCM), the central computer of your vehicle. A faulty PCM can wreak havoc on everything from fuel economy and transmission shifting to basic engine stability. I’ve spent two decades in the garage, and I’ve seen firsthand how a bad PCM can make a perfectly good engine run poorly, often leading to misdiagnosed and expensive repairs. This isn’t just a part; it’s the solution to getting your workhorse back on the road and running right.
This is a reliable, tested, and VIN-programmed replacement PCM for your GM vehicle. We take a quality, inspected module from a salvaged vehicle and flash it with the latest official GM software specific to your van’s Vehicle Identification Number (VIN). This means no expensive trips to the dealership for programming. It arrives at your door ready for installation, saving you time, money, and frustration. Getting your van back in service shouldn’t be a complicated ordeal, and with this module, it won’t be.
From the Diagnostic Bay
A customer brought in his ’99 Express van, a sister to the Savana, with a complaint of intermittent stalling and harsh shifting. He’d already replaced the fuel filter and a couple of sensors with no luck. His scanner showed a P0601 (Internal Control Module Memory Check Sum Error). This code is a dead giveaway. We swapped in a VIN-programmed PCM like this one, and the difference was immediate. The engine smoothed out, the transmission shifted perfectly, and the check engine light was gone for good. It’s a reminder that sometimes the most complex problems have a straightforward, central cause.
Is Your GM Truck or Van Showing These Signs?
A failing PCM can manifest in various ways. If you’re experiencing any of the following, your engine computer could be the culprit:
- ✔ Check Engine Light is on, often with codes like P0601, P0602, P0604, or P0606.
- ✔ Your vehicle fails to start or has difficulty starting.
- ✔ Noticeable drop in fuel efficiency for no apparent reason.
- ✔ Engine stalling, stuttering, or misfiring.
- ✔ Harsh or erratic automatic transmission shifting.
- ✔ Communication errors with your diagnostic scan tool.
Your Straightforward PCM Installation Guide
Installing your pre-programmed 1998-1999 Savana 3500 PCM is a manageable job for a DIYer. Follow these steps carefully for a smooth replacement.
- Safety First: Always disconnect the negative terminal from your vehicle’s battery and wait at least 10 minutes to allow the system to fully discharge.
- Locate the PCM: On most Savana/Express vans, the PCM is located in the engine compartment, typically on the driver’s side near the battery or air filter housing.
- Disconnect Wiring Harnesses: Carefully unplug the electrical connectors from the old PCM. These connectors have locking tabs that need to be released. Do not force them. Note their color and position.
- Remove the Old Module: Unbolt the PCM from its mounting bracket. Keep the hardware, as you may need it for the new module.
- Install the New PCM: Mount your new, pre-programmed module in the same location. Reconnect the wiring harnesses securely, ensuring they click into place.
- Final Steps: Reconnect the negative battery terminal. The vehicle may require a security relearn procedure, which typically involves turning the key to the ‘ON’ position for 10-15 minutes before starting. Consult your owner’s manual for specific instructions.
Verified Fitment for Your Vehicle
This module, identified by part number 09355699, is a direct replacement for a wide range of GM trucks and vans. It is compatible with several other service numbers including 16266645, 16250279, 16258815, and 09366810. Please confirm your vehicle is on this list and that your original module carries one of these part numbers for guaranteed compatibility.
CHEVROLET 2500 PICKUP 98-99 (Gasoline)
CHEVROLET 3500 PICKUP 98-99 (Gasoline)
EXPRESS 1500 VAN 98-99
EXPRESS 2500 VAN 98-99 (Gasoline)
EXPRESS 3500 VAN 98-99 (Gasoline)
GMC 1500 PICKUP 98-99 (Gasoline)
GMC 2500 PICKUP 98-99 (Gasoline)
GMC 3500 PICKUP 98-99 (Gasoline)
SAVANA 1500 VAN 98-99
SAVANA 2500 VAN 98-99 (Gasoline)
SAVANA 3500 VAN 98-99 (Gasoline)
CADILLAC ESCALADE 99
CHEVROLET SUBURBAN 1500/2500 98-99 (Gasoline)
CHEVROLET TAHOE 98-99 (Gasoline)
GMC YUKON 98-99
ASTRO VAN 98
BLAZER S10/JIMMY S15 98 (w/o build date opt ZN4)
BRAVADA 98 (w/o build date opt ZN4)
ENVOY 98 (w/o build date opt ZN4)
ISUZU HOMBRE 98 (4.3L, w/o build date opt ZN4)
SAFARI (GMC) 98
S10/S15/SONOMA 98 (4.3L, w/o build date opt ZN4)
Frequently Asked Questions
Do I need to do any programming myself?
No. We handle all the programming for you before shipment. Just provide your vehicle’s VIN during checkout, and the module will arrive ready to install with the latest GM software for your specific vehicle.
Is this a new part?
This is a high-quality, used OEM part sourced from a salvaged vehicle. Each unit is thoroughly inspected and tested to ensure it meets factory specifications before being programmed and shipped.
What is the security relearn procedure?
For many GM vehicles of this era, the anti-theft system (Passlock/VATS) needs to sync with the new PCM. This is usually done by turning the ignition to the ‘ON’ position for 10-15 minutes, then OFF, then starting the engine. It’s a simple process that does not require special tools.
Will this fix my transmission problems?
The PCM controls both engine and transmission functions. If your shifting problems are caused by faulty electronic commands from the computer, then yes, replacing the PCM will resolve them. However, it will not fix internal mechanical issues within the transmission itself.
How do I find my original part number?
The part number is printed on a sticker on the case of your current PCM. You will need to locate and remove the module to read it. Match it to 09355699 or one of the alternate numbers listed to ensure compatibility.