Restore Peak Performance to Your GM Truck or Van
Is your Chevrolet Express or GMC Savana van running rough, stalling unexpectedly, or showing a persistent Check Engine Light? These are classic signs of a failing Powertrain Control Module (PCM), the computer that serves as the brain for your vehicle’s engine and transmission. A faulty PCM can cause a cascade of frustrating issues, from poor fuel mileage and failed emissions tests to a vehicle that won’t start at all. This isn’t just an inconvenience; it’s a reliability problem that can leave you stranded. As a technician with over two decades of experience, I’ve seen countless drivers replace sensors and other parts, only to find the root cause was the PCM all along.
This replacement PCM is the straightforward, reliable solution you need. It’s a tested, functional unit sourced from a salvaged vehicle, offering a dependable fix without the high cost of a new-from-dealer part. The most significant benefit? We flash it with the latest GM software updates and program it specifically to your vehicle’s Vehicle Identification Number (VIN) before it ships. This means no expensive trips to the dealership for programming. It arrives ready for installation, making this a job that a confident DIYer or any professional mechanic can handle with ease. Get your workhorse back on the road with a reliable 1998-1999 Express 2500 PCM that restores factory performance and drivability.
A Technician’s Notebook: The Ghost in the Machine
I remember a 1999 Suburban that came into my bay with a complaint of intermittent stalling and hard shifting. The owner had already replaced the throttle position sensor and the mass air flow sensor, but the problems persisted. No specific sensor codes were present, just a generic P0606 (PCM Processor Fault) that would pop up occasionally. After verifying the power and ground circuits to the PCM were solid—a critical first step—we knew the module itself was the culprit. The internal processor was failing under heat and load. We installed a VIN-programmed PCM just like this one, performed the security relearn, and the truck ran perfectly. It saved the customer hundreds in further diagnostic fees and unnecessary parts.
Is Your Van Exhibiting These PCM Failure Signs?
A failing PCM can manifest in many ways. If you’re experiencing any of the following, this module is likely the solution you need. Look out for:
- ✔ Check Engine Light is on with codes like P0601 (Internal Memory Checksum Error) or P0606 (PCM Processor Fault).
- ✔ The engine cranks but refuses to start.
- ✔ Unexplained drops in fuel economy.
- ✔ Harsh or erratic automatic transmission shifting.
- ✔ The engine stalls for no apparent reason, either at idle or while driving.
- ✔ Failure to pass a state emissions inspection.
Your Straightforward PCM Installation Guide
Installing your replacement 1998-1999 Express 2500 PCM is a manageable job. While specific locations vary slightly by model, the general process is the same. Always consult a service manual for your exact vehicle if unsure.
- Safety First: Disconnect the negative terminal from your vehicle’s battery and secure it away from the post to prevent accidental contact.
- Locate the PCM: On most of these GM vans and trucks, the PCM is located in the engine compartment, typically on the driver’s side fender well or near the battery.
- Disconnect the Harnesses: Carefully unplug the electrical connectors from the old PCM. These connectors have locking tabs that need to be released. Do not force them.
- Remove the Old Module: Unbolt the old PCM from its mounting bracket and remove it from the vehicle.
- Install the New Module: Mount your new, pre-programmed PCM onto the bracket and securely plug in the electrical connectors. You should hear or feel a click as they lock into place.
- Reconnect the Battery: Re-attach the negative battery terminal.
- Perform Security Relearn (If Necessary): On these GM vehicles, you will likely need to perform a simple security relearn procedure, also known as the CASE learn. This can typically be done without special tools and involves turning the key to the ‘ON’ position for 10-15 minutes, then off, and repeating two more times before starting the engine. This allows the vehicle’s anti-theft system to recognize the new PCM.
Verified Fitment For Your GM Vehicle
This module, identified by part number 9366810 or service number 09355699, is a direct replacement for a wide range of GM trucks and vans. Please match your part number or verify your vehicle is on this list for guaranteed compatibility. It is a direct fit for the following vehicles with matching options:
BLAZER S10/JIMMY S15 98 (RH front), w/o build date opt ZN4; ID 9355699
BRAVADA 98 (6-262, 4.3L), w/o build date opt ZN4; ID 9355699
CHEVROLET 1500 PICKUP 98-99 (Gasoline, LH engine compartment), ID 9355699
CHEVROLET 2500 PICKUP 98-99 (Gasoline, LH front engine compartment), ID 9355699
CHEVROLET 3500 PICKUP 98-99 (Gasoline, LH front engine compartment), ID 9355699
ENVOY 98 (RH front), w/o build date opt ZN4; ID 9355699
ESCALADE 99 (LH front engine compartment), ID 9355699
EXPRESS 1500 VAN 98-99 (ID 9355699)
EXPRESS 2500 VAN 98-99 (Gasoline, ID 9355699)
EXPRESS 3500 VAN 98-99 (Gasoline, ID 9355699)
GMC 1500 PICKUP 98-99 (Gasoline, LH engine compartment), ID 9355699
GMC 2500 PICKUP 98-99 (Gasoline, LH front engine compartment), ID 9355699
GMC 3500 PICKUP 98-99 (Gasoline, LH front engine compartment), ID 9355699
ISUZU HOMBRE 98 (4.3L), w/o extended build date opt ZN4; ID 9355699
S10/S15/SONOMA 98 (6-262, 4.3L), w/o build date opt ZN4; ID 9355699
SAFARI (GMC) 98 (LH front by battery), ID 9355699
SAVANA 1500 VAN 98-99 (ID 9355699)
SAVANA 2500 VAN 98-99 (Gasoline, ID 9355699)
SAVANA 3500 VAN 98-99 (Gasoline, ID 9355699)
SUBURBAN 1500 98-99 (Gasoline, LH front engine compartment), ID 9355699
SUBURBAN 2500 98-99 (Gasoline, LH front engine compartment), ID 9355699
TAHOE 98-99 (Gasoline, LH front engine compartment), ID 9355699
YUKON 98-99 (LH engine compartment), ID 9355699
This unit is also a direct replacement for part numbers: 09355699, 16266645, 16250279, 16258815, and 9366810.
Frequently Asked Questions
Frequently Asked Questions
Do I need to do any programming myself?
No. We program the module to the VIN you provide before we ship it. It arrives ready for installation. You will, however, need to perform the simple security relearn procedure after installation.
What is the security relearn / CASE learn procedure?
It’s a simple process that syncs the new PCM with your vehicle’s anti-theft system. It typically involves a sequence of key turns and waiting periods and does not require any special scan tools. Instructions are widely available online for your specific model.
Is this a new part?
No, this is a high-quality, tested used part that has been sourced from a salvaged vehicle. This allows us to offer a reliable, cost-effective solution that has been flashed with the latest available software from GM.
How do I provide my VIN?
After you complete your purchase, simply send us a message with your 17-digit Vehicle Identification Number (VIN). We cannot ship the module until we receive your VIN, as programming is a required step.
Will this fix my transmission shifting problems?
In many cases, yes. The PCM controls both engine and transmission functions. If the module is faulty, it can cause poor shift commands. This replacement 1998-1999 Express 2500 PCM is often the correct fix for electronically-caused shifting issues.
What if my part number is slightly different?
This module replaces several part numbers, including 09355699, 16266645, 16250279, and more. As long as your vehicle is on the compatibility list and your original module looks identical, this unit will function correctly once programmed to your VIN.