Diagnostic Procedure No. 6: Description
WARNING: This page is about a different car, the 2001 Nissan Sentra. However, it is still accessible from the selected car via links, so may be relevant.
When 5 or more attempts to start engine are consecutively performed using an unregistered ignition key or there is an IMMU or ECM malfunction, NATS will activate LOCK MODE, preventing the engine from being started. LOCK MODE should be displayed on CONSULT under SELF-DIAGNOSIS - DTC RESULTS.