i-Butler is an onboard conversational AI assistant that predicts vehicle health using vehicle sensor, driving, and environmental data, then explains its findings in plain language. Its hybrid architecture combines a 2.3-billion-parameter onboard multimodal model with a cloud-based LLM, maintaining essential functions offline and responding in approximately 300 milliseconds. AI-powered Prognostics and Health Management detects early signs of degradation in brake, tire, battery, and steering systems—up to 1,000 miles before a predicted fault and well before a warning light appears. It then explains the likely cause, risk level, when service is needed, and recommended action at a level suited to each user. Selected functions, including drive-mode selection and cabin ventilation, can be controlled by voice. During autonomous operation, i-Butler uses In2itive Twin visualization to explain vehicle behavior and the control responses behind it. In emergencies, it recommends next steps and, with user consent, initiates contact with emergency services and insurance providers.