1985-1988 Nissan Common OBD-I Codes

-Verify that diagnostic mode selector is turned fully counterclockwise.
-Turn ignition switch ON.
-Make sure inspection lamps stay on. (Bulb check.)
-Ture diagnostic mode selector fully clockwise.
-Make sure inspection lamps display code 23 and 31.
-Depress accelerator pedal and release.
-Make sure inspection lamps display code 31.
-Start engine, apply brakes and shift into “D” position.
-Make sure inspection lamps display code 31.
-Turn a load switch OFF-ON-OFF. (A/C switch, Headlight switch etc.)
-Shift into “P”.
-Make sure inspection lamps display code 44. Any other code is a DTC.