Programmed 2008 Express 3500 Van ECM | Engine Control Module 12612384

Restore Peak Performance to Your GM Vehicle

Is your 2008 Express 3500 Van or another GM vehicle suffering from perplexing issues like a persistent check engine light, rough idling, stalling, or poor fuel economy? These are classic signs of a failing Engine Control Module (ECM), the electronic brain of your vehicle. When the ECM falters, it can disrupt everything from fuel injection to transmission shifting, making your vehicle unreliable and frustrating to drive. This replacement ECM, part number 12612384, is the definitive solution to restore your vehicle’s performance and dependability.

As a technician with over two decades of experience, I’ve seen firsthand how a faulty ECM can lead to costly and time-consuming misdiagnoses. Mechanics might chase ghosts, replacing perfectly good sensors and parts, when the root cause lies within the module itself. This unit eliminates that guesswork. We take the hassle out of the repair by pre-programming this module with the latest official GM software specifically for your vehicle. All we need is your Vehicle Identification Number (VIN) at checkout. This means no expensive trips to the dealership for programming—it’s ready for installation right out of the box.

Is Your GM Vehicle Showing These ECM Failure Signs?

A failing ECM can manifest in numerous ways. If you’re experiencing any of the following, it’s a strong indicator that your module may need replacement:

• ✔ Persistent Check Engine Light (CEL)
• ✔ Diagnostic Trouble Codes (DTCs) such as P0601, P0602, P0606, or other U-codes (communication errors)
• ✔ Unexplained drop in fuel efficiency
• ✔ Engine stalling, stumbling, or misfiring
• ✔ Harsh or erratic automatic transmission shifting
• ✔ Complete no-start or intermittent starting problems
• ✔ Issues with other electronic systems that communicate with the ECM

A Straightforward Guide to Your ECM Installation

Installing your new ECM is a manageable job for a confident DIYer or any professional technician. Our pre-programming service handles the most complex step for you. Follow these general steps for a successful installation.

1. Safety First: Always disconnect the negative terminal from your vehicle’s battery and wait at least 15 minutes for capacitors to discharge before beginning work.
2. Locate the ECM: On the 2008 Express 3500 Van, the ECM is typically located in the left rear of the engine compartment. For other models, refer to the fitment list below for its general location (e.g., under the battery, on the firewall).
3. Disconnect Connectors: Carefully unclip and remove the wiring harness connectors from the old ECM. Inspect the connectors for any signs of corrosion or damage and clean them if necessary.
4. Remove the Old Module: Unbolt the old ECM from its mounting bracket and remove it from the vehicle.
5. Install the New Module: Mount your new, pre-programmed ECM in the same location and secure it with the original bolts.
6. Reconnect Everything: Firmly re-attach the wiring harness connectors to the new module. Reconnect the negative battery terminal.
7. Perform Security Relearn: Most GM vehicles of this era require a security relearn procedure to sync the new ECM with your vehicle’s anti-theft system. This can typically be done without special tools by cycling the key. A common method is: Turn the key to ‘ON’ for 10 minutes, ‘OFF’ for 10 seconds, and repeat this cycle three times. Your vehicle should then start.

Verified Vehicle Compatibility List

This module is a direct replacement for part numbers 12612384, 12622141, and 12617568. It is guaranteed to fit the following vehicles and configurations:

Frequently Asked Questions

Do I need to do anything after installing this ECM?

Yes. While we handle the main programming, you will need to perform a simple security relearn procedure (also known as a VATS relearn). This process syncs the new module to your vehicle’s anti-theft system and typically involves cycling the ignition key. Instructions are widely available online for your specific model.

How do I provide my VIN number?

After you complete your purchase, you will receive instructions on how to send us your vehicle’s 17-digit VIN. We cannot program and ship your module without it, so please provide it promptly to avoid delays.

Is this a brand new part?

This is a high-quality, tested, and verified OEM replacement part that has been professionally prepared and programmed to ensure it meets or exceeds original factory specifications. It is not a new part from the dealer.

Will this fix my vehicle’s transmission problems?

In many modern vehicles, the ECM also controls transmission functions. If your shifting problems are caused by faulty signals or processing errors from a bad ECM, then yes, this new module can resolve them. However, it will not fix mechanical issues within the transmission itself.

What if I order the wrong part?

Please use the detailed compatibility list on this page to verify fitment before ordering. Since each module is specifically programmed for a customer’s VIN, it’s crucial to ensure you are purchasing the correct part for your vehicle’s year, make, and model.