Mercedes-Benz C400 / C450 / C43 ECU Removal Guide

Important: Please SCAN your vehicle before removing the ECU. This can be done at your local parts store or mechanic. They will plug into the vehicle's OBD2 port and scan for any existing codes. After scanning, unplug the negative side of the battery to avoid any lights or issues when unplugging or reinstalling the ECU. In some cases, the ECU may need to be shipped in to be reset. Please be sure to leave the doors unlocked and the hood popped to ensure you have access to reinstall the ECU. Failure to follow these steps may cause issues to your vehicle for which AMR Performance is not responsible. Step 1: Open the Hood Open your vehicle's hood to access the engine bay. Step 2: Locate the ECU The ECU can be seen in the center of the engine bay under the front engine cover. First, we need to remove the engine cover. Step 3: Remove the Engine Cover (Rear) Lift back on each corner of the rear section of the engine cover. You will notice it will "pop" up easily with little effort. Step 4: Disconnect Front Clips On the front portion of the engine cover, you will see two clips connected to the air duct. Pull back on these clips gently. Step 5: Set Engine Cover Aside Once removed, place the engine cover to the side. Step 6: ECU Now Visible You can now see the ECU located in the center of the engine bay. Step 7: Locate ECU Connectors At the rear of the ECU, you will see the two ECU connectors. Step 8: Unlock Driver Side Connector Unlock the driver side ECU connector by releasing the locking tab. Step 9: Unlock Passenger Side Connector Unlock the passenger side ECU connector using the same method. Step 10: Remove the ECU Pull up on the front of the ECU — you will notice it will "unclip." Do the same for the rear. ECU Removed! Congratulations! The ECU has been successfully removed. Reinstallation Notes When receiving your ECU back: Please ensure that you carefully reinstall the factory clips onto the ECU gently. Once the ECU is reinstalled correctly, reconnect your battery and start your vehicle. Failure to do so can cause the vehicle to not start, not run correctly, or cause damage to the ECU. If you have any questions about this process, contact AMR Performance for assistance.