Abstract
The paper aims to classify the maintenance of internal combustion engines in 812 series diesel multiple units, to analyse operating failures, and to identify methods and procedures for determining their current mechanical condition. The paper specifies the required procedures and methods for maintenance starting from the development of the DMU (diesel multiple units) 812 series to the present. It also focuses on understanding how diagnosis and control sensors are attached in individual cable harnesses. A protocol for diagnosing combustion engine defects is proposed in the final part of the paper. A part of the paper is a proposed list of codes for individual faults to facilitate the work. Another method proposed within this paper is the definition and attachment of individual sensor connections on the engine in the EDC (Electronic Diesel Control) M(S) 5 cable harness. Faults leading to engine stop are identified.