Software complexity of vehicles is constantly growing especially with additional autonomous driving features being introduced. This increases the risk for bugs in the system, when the car is delivered. According to a car manufacturer, more than 90% of availability problems corresponding to Electronic Control Unit (ECU) functionality are either caused by software bugs or they can be resolved by applying software updates to overcome hardware issues. The main concern are sporadic errors which are not caught during the development phase since their trigger condition is too unlikely to occur or is not covered by the tests. For such systems, there is a need of safe and secure infield diagnosis. In this paper we present a tool software architecture with remote access, which facilitates standard read/write access, an efficient channel interface for communication and file I/O, and continuous trace. This enables the remote access of latest automotive Microcontroller Units (MCUs)’ trace systems, which provide non-intrusive system observation without compromising safety, security, or real-time performance. The tool access architecture is designed such that the physical interface is agnostic for the tool. A target can be connected with any standard tool interface as well as with Ethernet. With today’s increased silicon performance, Ethernet can be a viable option as tool interface, from development to the field. The implementation includes an agent firmware that can either run on an application core or as a sand-boxed sub-task of the security core. With the next generation vehicles’ E/E architectures moving towards an Ethernet backbone, this gives developers an option to include remote access to target systems without additional tool hardware.