Restore Peak Performance to Your Workhorse Truck
Is your 1998-1999 Chevrolet 3500 Pickup running rough, stalling unexpectedly, or throwing a stubborn Check Engine Light? You’re not just dealing with an annoyance; you’re facing a potential breakdown that could cost you time and money. The Powertrain Control Module (PCM), the electronic brain of your truck’s engine and transmission, is often the culprit. After 20+ years on the road, these original units are prone to failure. This isn’t just a replacement part; it’s a reliable, straightforward solution to get your truck back to operating as it should.
This is a genuine, road-tested PCM sourced from a salvaged vehicle. We take the guesswork and hassle out of the repair by programming it specifically for your truck. Simply provide your Vehicle Identification Number (VIN) after your purchase, and our technicians will flash the module with the latest, most stable software updates directly from GM. This ensures perfect compatibility and function, right out of the box. You get a dependable part that’s ready to install, without the high cost or programming fees of a dealership.
From the Diagnostic Bay: The Ghost in the Machine
I remember a 1999 GMC Sierra 3500 (a cousin to this Chevy) that came into my shop with a problem that was driving the owner crazy. The truck would randomly stall at stoplights, but then start right back up. He’d already replaced the fuel pump and ignition coil with no luck. The only code stored was a P0601 (Internal Control Module Memory Check Sum Error). This code is a direct indictment of the PCM itself. The internal memory circuits had started to degrade, causing these intermittent failures. We installed one of our pre-programmed PCMs, and the problem was solved instantly. The truck ran smoother than it had in years. This is a classic example of how a failing 1998-1999 Chevrolet 3500 PCM can create phantom issues that seem unrelated.
Is Your Truck Showing These Symptoms?
A failing PCM can manifest in numerous ways. If you’re experiencing any of the following, this module is the likely solution:
- ✔ Persistent Check Engine Light (CEL)
- ✔ Unexplained engine stalling or misfires
- ✔ Harsh or erratic automatic transmission shifting
- ✔ No-start or difficult starting conditions
- ✔ Poor fuel economy
- ✔ Communication error codes, such as U0100
- ✔ Specific PCM failure codes like P0601, P0602, P0605, or P0606
A Straightforward Guide to Installation
Replacing the 1998-1999 Chevrolet 3500 PCM is a job most DIYers can handle with basic tools. Because we program it to your VIN, you can often avoid a costly trip to the dealer for additional procedures.
- Safety First: Disconnect the negative terminal from your truck’s battery to prevent any electrical shorts.
- Locate the PCM: On most of these trucks, you’ll find the PCM in the engine compartment, typically on the driver’s side near the fender or firewall.
- Disconnect Connectors: Carefully unplug the large wiring harness connectors from the old PCM. There are usually release tabs that need to be pressed or lifted. Avoid pulling on the wires themselves.
- Remove the Old Module: Unbolt the PCM from its mounting bracket. It’s typically held in by a few 10mm or 13mm bolts.
- Install the New Module: Seat your new, pre-programmed PCM into the bracket and secure it with the bolts.
- Reconnect Everything: Firmly plug the wiring harnesses back into the new PCM. You should hear or feel a click as they lock into place. 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 system to initialize. Start your truck and check for proper operation.
Verified Vehicle Compatibility
This module, identified by service ID 9355699, is compatible with a wide range of General Motors trucks and vans. It directly replaces part numbers 09355699, 16266645, 9355699, 16250279, 16258815, 09366810, and 9366810. Please verify your vehicle is on the list below. This is a crucial step for a successful repair of your 1998-1999 Chevrolet 3500 PCM or other compatible vehicle.
- ASTRO 98 (LH front by battery)
- BLAZER S10/JIMMY S15 98 (RH front engine compartment)
- BRAVADA 98 (w/o build date opt ZN4)
- CADILLAC ESCALADE 99 (LH front engine compartment)
- CHEVROLET 1500 PICKUP 98-99 (Gasoline, LH engine compartment)
- CHEVROLET 2500 PICKUP 98-99 (Gasoline, LH front engine compartment)
- CHEVROLET 3500 PICKUP 98-99 (Gasoline, LH front engine compartment)
- ENVOY 98 (RH front engine compartment, w/o build date opt ZN4)
- EXPRESS/SAVANA 1500 VAN 98-99
- EXPRESS/SAVANA 2500 VAN 98-99 (Gasoline)
- EXPRESS/SAVANA 3500 VAN 98-99 (Gasoline)
- GMC 1500 PICKUP 98-99 (Gasoline, LH engine compartment)
- GMC 2500 PICKUP 98-99 (Gasoline, LH front engine compartment)
- GMC 3500 PICKUP 98-99 (Gasoline, LH front engine compartment)
- ISUZU HOMBRE 98 (4.3L, w/o extended build date opt ZN4)
- SAFARI (GMC) 98 (LH front by battery)
- S10/S15/SONOMA 98 (4.3L, w/o build date opt ZN4)
- SUBURBAN 1500/2500 98-99 (Gasoline, LH front engine compartment)
- TAHOE/YUKON 98-99 (Gasoline, LH engine compartment)
Frequently Asked Questions
What is a PCM and why does it need programming?
The Powertrain Control Module (PCM) is your vehicle’s main computer, managing engine and transmission functions. Programming, or ‘flashing’, installs vehicle-specific software using your VIN, ensuring it communicates correctly with all the sensors and components on your particular truck.
Is this part difficult to install?
No, this is a very DIY-friendly part for those with basic mechanical skills. Since we pre-program the module, it’s typically a plug-and-play installation. You just need basic hand tools to swap the physical unit.
What happens after I place my order?
After you complete your purchase, you will need to send us your 17-digit VIN. Our technicians will then program this PCM with the latest GM software for your exact vehicle before shipping it to you.
Is a used part reliable?
Absolutely. These are OEM units that have been tested for functionality. Sourcing a quality used part is a cost-effective and dependable way to fix your vehicle compared to aftermarket alternatives or expensive new parts.
Will this fix my Check Engine Light?
If the Check Engine Light is caused by an internal PCM failure (like codes P0601-P0606), then yes, this will resolve the issue. However, you should always diagnose the codes to ensure the problem isn’t a faulty sensor or wiring.