Automotive field failure analysis based on mileage — Feasibility & benefits

Most failures in the automotive systems depend on age and accumulated usage. Typically, these systems are covered under warranty for months-in-service (i.e. MIS/age) and a certain amount of usage (mileage) after the sales of the products. Warranty analysis of these systems enables manufacturers to understand field failures, and identify focus areas to make product improvements. Typically warranty analysis is performed based on MIS. However, mileage based warranty analysis has two added benefits - (1) some failures are, by their physical nature, related to mileage rather than age. Hence, mileage is a better indicator for observing and quantifying these failures. (2) Our observations also indicate that most vehicles leave warranty due to the mileage restrictions to the warranty coverage, rather than MIS. In such a scenario, mileage-based warranty calculations can provide us with early information. Warranty analysis based on mileage has been presented in the literature as a supplement to the traditional MIS based analysis. However, these are based on the following two major assumptions, and their validity has not been established yet: · The accumulation of miles is approximately linear with age. · The distribution of mileage accumulation rate in vehicles without any claims is same as that of vehicles which have at least one warranty claim. Using the real-time diagnostic data collected from Telematics systems, this work demonstrates that the above two assumptions are valid. As a result, we can achieve accurate warranty rates and take the advantage of early detection of problems using mileage. Early detection is based on high usage vehicles. We also demonstrate that the proportion of such vehicles is statistically significant, which enables mileage based analysis feasible earlier than age based analysis. This lead time is of crucial importance to the OEMs, especially close to the launch of new products, where they can identify and rectify field failures early.