OBD Function
WARNING: This page is about a different car, the 2018 Nissan NV3500 HD and 2018 Nissan NV2500 HD. However, it is still accessible from the selected car via links, so may be relevant.
The ECM provides emission-related on board diagnostic (OBD-II) functions for the A/T system.
One function is to receive a signal from the TCM used with OBD-related parts of the A/T system. The signal is sent to the ECM when a malfunction occurs in the corresponding OBD-related part.
The other function is to indicate a diagnostic result by means of the MIL (malfunction indicator lamp) on the instrument panel. Sensors, switches and solenoid valves are used as sensing elements.
The MIL automatically illuminates in "One or Two Trip Detection Logic" when a malfunction is sensed in relation to A/T system parts. For details, refer to 1st Trip Detection Logic and Two Trip Detection Logic .