Programmed 1998-1999 Chevrolet 2500 Pickup PCM 16266645 | VIN Matched

Restore Your Truck’s Performance and Reliability

If your late-90s Chevy truck is suffering from baffling issues like random stalling, no-start conditions, erratic shifting, or a persistent check engine light, the culprit is often the Powertrain Control Module (PCM). As a technician with over two decades of experience, I’ve seen countless hours and dollars wasted chasing down what seems like a fuel or sensor problem, when the vehicle’s computer brain was the root cause all along. This is the central command unit for your engine and transmission, and when it fails, it can create a cascade of frustrating symptoms. This isn’t just an inconvenience; it’s a reliability issue for a truck you depend on.

We offer a straightforward, dependable solution. This is a tested, genuine GM PCM, sourced from a salvaged vehicle, that solves these common problems. The most critical part of the process is the programming, and we handle that for you. Before we ship it, we flash the module with the latest GM-approved software updates, specifically matched to your truck’s Vehicle Identification Number (VIN). This ensures that all factory parameters for fuel delivery, spark timing, and transmission control are perfectly calibrated for your exact vehicle configuration. You get a reliable part that’s ready to install right out of the box, saving you a costly trip to the dealership and the hassle of finding a shop with the right programming equipment.

Is Your Truck Showing These Symptoms?

• ✔ Unexplained Check Engine Light with codes like P0601 (Internal Control Module Memory Check Sum Error) or other communication-related faults.
• ✔ Engine cranks but refuses to start, even with good fuel pressure and spark.
• ✔ Harsh, erratic, or delayed automatic transmission shifting.
• ✔ Poor fuel economy or a noticeable loss of engine power.
• ✔ Intermittent stalling, especially after the engine has warmed up.
• ✔ Communication issues with diagnostic scan tools.

A Straightforward Guide to Installation

Replacing the 1998-1999 Chevrolet 2500 Pickup PCM is a job most DIYers can handle with basic tools. Since we’ve pre-programmed it to your VIN, no further software work is needed. Just follow these steps carefully.

1. Safety First: Disconnect the negative terminal from your truck’s battery to prevent any electrical shorts.
2. Locate the PCM: On most of these trucks, the PCM is located in the engine compartment on the driver’s side, near the fender or firewall. It’s a silver metal box with several large multi-pin electrical connectors.
3. Disconnect the Connectors: Carefully unclip and remove all electrical harness connectors from the old PCM. These connectors have locking tabs that need to be released. Avoid pulling on the wires themselves.
4. Remove the Old Module: Unbolt the old PCM from its mounting bracket. Keep the hardware, as you may need to reuse it.
5. Install the New Module: Mount your new, pre-programmed PCM onto the bracket and secure it with the bolts.
6. Reconnect Everything: Firmly plug the electrical connectors into the new PCM until they click into place. Double-check that all are secure. Reconnect the negative battery terminal.
7. Perform Security Relearn (If Necessary): In some cases, a security relearn procedure may be required. This typically involves turning the key to the ‘ON’ position for 10-15 minutes, then off, and repeating two more times. Your truck’s service manual will have the specific procedure.

Will This Fit My Vehicle?

This PCM is a direct fit for a wide range of GM vehicles and is a replacement for multiple part numbers, including 16266645, 09355699, 16250279, and more. Please verify that your vehicle and its options are on the list below. The critical identifier is the service ID 9355699 on your original module.