Lock-Up/Overdrive Control & Self-Diagnosis (300ZX): Self-Diagnosis

1. Turn overdrive control switch to "O/D". Turn ignition switch "ON", but DO NOT  start engine. Without depressing accelerator pedal, manually press kickdown switch on, for more than one second. Start engine and run vehicle about 12 MPH. Check for any abnormal conditions.
2. Turning ignition switch "OFF" or to "ACC", will cancel self-diagnosis function and step  1 must be repeated. If abnormalities are noted, proceed to next step. If no abnormalities are noted, see LOCK-UP & OVERDRIVE CONTROL  .
3. If power shift indicator flickers at intervals of one second at speeds 8-9 MPH and before 1-2 shift occurs, check for broken wiring between shift switch and LCU harness. If wiring is good, shift switch is malfunctioning.
4. If power shift indicator flickers at intervals of one second in 2nd gear or above speeds of 8-9 MPH, vehicle speed sensor is defective or wiring between speed sensor and LCU is broken. See Fig 1 .
5. If power shift indicator flickers at intervals of 1/4 second, throttle sensor is defective, wiring harness is broken between the throttle sensor and the LCU, or the LCU is malfunctioning. See Fig 1 for throttle sensor test.

Fig 1: Lock-Up Control Unit Test Chart (300ZX)