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Home >> Lexus >> 1999 >> LS 400 >> Repair and Diagnosis >> Steering >> Steering Column >> Power Tilt Steering Column Systems >> Circuit Tests >> Sensor Power Source Circuit
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Sensor Power Source Circuit

  1. Turn ignition on. Remove tilt and telescopic ECU with wiring harness connector attached. Using a voltmeter, measure voltage by backprobing rear of 22-pin ECU connector T9 between terminals No. 12 (Black/Blue wire) and No. 4 (White wire). See Figure. Also, measure voltage by backprobing rear of 22-pin ECU connector T9 between terminals No. 13 (White/Red wire) and No. 5 (White/Blue wire). If voltage is not 4.5-5.5 volts for both measurements, go to step  3. If voltage is 4.5-5.5 volts for both measurements, go to next step.
  2. Check wiring harness and connectors for an open between tilt and telescopic ECU, tilt motor and telescopic motor. See WIRING DIAGRAMS . Repair or replace as necessary. If wiring harness and connectors are okay, go to next test listed in SYMPTOM DIAGNOSIS  table under TROUBLE SHOOTING.
  3. Check wiring harness and connectors for a short between tilt and telescopic ECU, tilt motor and telescopic motor. See WIRING DIAGRAMS . Repair or replace as necessary. If wiring harness and connectors are okay, check tilt and telescopic ECU. See TILT & TELESCOPIC ECU PIN VOLTAGE TESTS  under COMPONENT TESTS. Replace tilt and telescopic ECU as necessary and retest system operation.
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