OBD SYSTEM READINESS function not yet complete
One or more of the following diagnostic trouble code detection conditions have not yet been satisfied. Performing the appropriate DRIVE MODE condition will clear P1000 from ECU memory and establishing SYSTEM READINESS. If, after performing all detection conditions, a fault is indicated, one or more of the following codes will be stored and appropriate OBD troubleshooting steps should be implemented.
DRIVE MODE Conditions
DRIVE MODE 1 - Fuel trim memory initialization
DRIVE MODE 2 - EGR system repair verification
DRIVE MODE 3 - Oxygen sensor and catalyst repair verification
DRIVE MODE 4 - Evaporative emissions system repair verification
OBD-II Compliance & 1995 Models
Early implementations (before 1996) of OBD-II utilize a non-standard method of determining SYSTEM READINESS using DTC P1000. Such vehicles are considered "OBD-I compliant" for emissions testing but are essentially OBD-II for troubleshooting purposes.
If no fault is indicated other than P1000 after several drive cycles, check for a blown ROOM fuse or faulty battery connections.
[P1000 - 1995 Mazda Millenia factory service manual]