You really don’t need to perform an ECU update when you install a cold air intake in a diesel. Most diesels use a turbo, and turbos circulate their own air supply which provides consistent warm air into the engine. Because a cold air intake cycles air through the engine in a similar fashion, your ECU is already programmed to accept this additional air flow. To ensure you don’t need to adjust your ECU setting, speak with your parts store associate. You can also check your turbo installation system or check your diesel turbo system for additional information.