The automotive conversion sector in Peru faces persistent inefficiencies in its service operations, mainly due to long delivery times, reprocessing, and the lack of standardized maintenance practices. This study addressed the urgent challenge of reducing operational delays that affected on-time delivery performance by applying Lean Service and Total Productive Maintenance (TPM) methodologies to standardize processes and enhance service efficiency. The analyzed company, dedicated to the customization and conversion of vehicles for high-end commercial use, reported an average delay rate of 58%, above the sector benchmark of 49%, and a service level of 65%, below the industry standard of 80%. A Lean Service model integrating the 5S methodology and TPM was implemented to optimize workspace organization, minimize idle time, and ensure equipment reliability. Data were collected from production logs, maintenance reports, and customer delivery records. The simulated results show a 35% reduction in the Delivery Time Index, a 20% improvement in service level, and a 15% increase in labor productivity. These findings demonstrate that the integration of Lean Service and TPM promotes standardization, operational stability, and customer satisfaction, providing a practical framework to improve service performance in automotive companies operating in emerging economies.