Diagnostic Modes
WARNING: This page is about a different car, the 1989 Nissan Pickup and 1989 Nissan Pathfinder. However, it is still accessible from the selected car via links, so may be relevant.
Five different diagnostic modes are available through the ECCS. Diagnostic modes 1 and 2 are used for monitoring the air/fuel mixture ratio using LED inspection lights. Mode 3 is the self diagnostic system, used for obtaining trouble codes for component or circuit failures. Mode 4 is used to determine if malfunction(s) are present in the on/off controlled switches of the system. Mode 5 is the real time diagnostic system, used for monitoring the system and its components during actual driving conditions, usually to simulate an intermittent condition.