Programmed 2008 Sierra 1500 Engine Control Module ECM PCM 12622141

Restore Your Truck’s Brainpower and Reliability

As a mechanic with two decades of experience under the hood, I can tell you that few things are more frustrating than chasing electronic gremlins. Your 2008 Sierra 1500 is a tough truck, but when its Engine Control Module (ECM)—the central computer—starts to fail, it can cause a cascade of baffling problems. From a truck that refuses to start, stalls at stoplights, or gets terrible gas mileage, a failing ECM can make your reliable workhorse feel unpredictable. This isn’t just an inconvenience; it’s a critical component failure that needs a solid, dependable solution.

This is not just a replacement part; it’s a complete fix. We take a genuine GM module (Part #12622141) and professionally program it to your truck’s specific Vehicle Identification Number (VIN). This means it arrives at your door loaded with the latest factory software updates from GM, tailored specifically for your vehicle’s configuration. You get to skip the expensive dealership visit for programming, turning a complex repair into a manageable weekend project for a DIYer or a quick, profitable job for a professional shop.

Is Your Sierra Showing These Signs of PCM Failure?

A faulty ECM can manifest in many ways. If you’re experiencing any of the following, this module is the likely solution:

• ✔ Check Engine Light is on with codes like P0601, P0606 (Internal Control Module Failure) or U-series communication codes.
• ✔ Engine cranks but refuses to start.
• ✔ Unexplained stalling, especially when coming to a stop or at idle.
• ✔ Noticeable decrease in fuel economy.
• ✔ Harsh or erratic automatic transmission shifting.
• ✔ Misfires or rough running even after replacing plugs and coils.
• ✔ Other modules (like the ABS or BCM) report losing communication with the engine computer.

Your Straightforward Installation Guide

Replacing the 2008 Sierra 1500 Engine Control Module is easier than you might think. With our pre-programmed unit, you’re already halfway there. Follow these general steps to get your truck back to peak performance.

1. Safety First: Always disconnect the negative terminal from your truck’s battery before starting any electrical work.
2. Locate the ECM: On most 2008 Sierra 1500 models, the ECM is located in the engine bay on the driver’s side, often under or near the battery tray.
3. Disconnect Connectors: Carefully release the locking tabs and unplug the large wiring harness connectors from the old module. Inspect them for any corrosion or damage.
4. Remove the Old Module: Unbolt the old ECM from its mounting bracket. It’s typically held in by a few bolts.
5. Install the New Module: Mount your new, pre-programmed ECM in place and securely tighten the bolts.
6. Reconnect Everything: Plug the wiring harness connectors firmly into the new module until they click into place. Reconnect your negative battery terminal.
7. Perform Security Relearn: This is a critical step. Even though the module is programmed, your truck’s anti-theft system needs to recognize it. The procedure is simple: Turn the key to the ‘ON’ position for 10-15 minutes, then turn it ‘OFF’ for 10 seconds. Repeat this cycle 3 times. On the fourth try, the truck should start.

Verified Compatibility for Your GM Vehicle

This module is a direct replacement for part numbers 12612384, 12622141, and 12617568 and fits a wide range of GM vehicles. Please confirm your model and options below: