Restore Peak Performance to Your Chevy Truck
If you’re dealing with frustrating, hard-to-diagnose issues on your 1998-1999 Chevrolet 2500 Pickup, the Powertrain Control Module (PCM) is often the culprit. As a technician with over two decades of experience under the hood, I’ve seen firsthand how a failing PCM can cause everything from a no-start condition to poor fuel economy and erratic shifting. It’s the brain of your engine and transmission, and when it’s not working correctly, your whole truck suffers. This isn’t just an inconvenience; it can be a reliability issue that leaves you stranded.
We offer a dependable and straightforward solution. This is a tested, used OEM PCM, part number 9355699, sourced from a salvaged vehicle. The real value here is in the service we provide before it ever leaves our facility. We will flash the module with the latest official GM software updates, specifically programmed to your truck’s unique Vehicle Identification Number (VIN). This critical step ensures compatibility and proper function, eliminating the guesswork and the need for an expensive trip to the dealership for programming. You get a part that’s ready to install and get your truck running right again.
From the Diagnostic Bay
I remember a 1999 GMC Sierra 2500 that came into the shop with a complaint of intermittent stalling at stoplights. The owner had already replaced the fuel pump and idle air control valve with no luck. No hard codes were present, just a pending P0606 (PCM Processor Fault) that would come and go. After running diagnostics, we found the PCM’s 5-volt reference signal would occasionally drop out. We swapped in a VIN-programmed PCM just like this one, performed the security relearn, and the truck ran perfectly. It’s a classic example of how a failing computer can mimic mechanical problems, making a reliable, correctly programmed 1998-1999 Chevrolet 2500 PCM the only true fix.
Is Your Truck Showing These PCM Failure Signs?
- ✔ Check Engine Light is on with codes like P0601, P0602, or P0606.
- ✔ The engine cranks but refuses to start.
- ✔ Unexplained drops in fuel efficiency.
- ✔ Harsh or erratic automatic transmission shifting.
- ✔ The engine stalls, stumbles, or misfires intermittently.
- ✔ Communication errors with your scan tool.
A Straightforward Guide to Your PCM Swap
Installing your replacement 1998-1999 Chevrolet 2500 PCM is a manageable job for a DIYer with basic tools. Follow these steps carefully to ensure a smooth installation.
- Safety First: Always disconnect the negative terminal from your truck’s battery and secure it away from the post.
- Locate the PCM: On most of these trucks, the PCM is located in the engine compartment, typically on the driver’s side fender well.
- Disconnect the Connectors: Carefully unclip and remove the wiring harness connectors. These older GM connectors have locking tabs that need to be released. Avoid pulling on the wires themselves.
- Remove the Old Module: Unbolt the PCM from its mounting bracket. There are usually two or three bolts holding it in place.
- Install the New Module: Seat your new, pre-programmed PCM into the bracket and secure it with the mounting bolts.
- Reconnect Everything: Firmly plug the wiring harnesses back into the correct sockets until they click. Reconnect your negative battery terminal.
- Perform Security Relearn: You will need to perform a security relearn procedure (often called a CASE learn) for the vehicle to start. This typically involves turning the key to ‘ON’ for 10-15 minutes, then ‘OFF’, and repeating two more times. Your truck’s service manual will have the exact procedure.
Will This Fit My Vehicle?
We guarantee this module will function correctly if your vehicle is listed below and your original part number matches. This PCM, ID 9355699, is a direct replacement for part numbers 09355699, 16266645, 16250279, 16258815, 09366810, and 9366810. Please verify the ID on your current module before ordering. This part fits a wide range of GM gasoline-powered vehicles, including:
- Astro / Safari (GMC): 1998
- Blazer S10 / Jimmy S15: 1998
- Bravada: 1998
- Chevrolet / GMC Pickup (1500/2500/3500): 1998-1999
- Escalade: 1999
- Envoy: 1998
- Express / Savana Van (1500/2500/3500): 1998-1999
- Hombre (Isuzu): 1998 (4.3L)
- S10/S15/Sonoma: 1998 (4.3L)
- Suburban (1500/2500): 1998-1999
- Tahoe / Yukon: 1998-1999
Note: This is a comprehensive but not exhaustive list. The key is matching the part ID number 9355699. If you’re unsure, please contact us with your VIN.
Frequently Asked Questions
1998-1999 Chevrolet 2500 PCM
Will this fix my transmission shifting problems?
In many cases, yes. The PCM controls transmission line pressure and shift points. If your module is failing, it can cause harsh shifts, delayed engagement, or hunting for gears. A properly functioning is vital for smooth transmission operation.