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

  1. Turn ignition off. Remove tilt and telescopic ECU with wiring harness connector attached. Using a voltmeter, measure voltage by backprobing rear of 18-pin ECU connector T10 between terminals No. 18 (Red wire) and No. 8 (Blue/Red wire). See Figure. If voltage is not 10-14 volts, go to next step. If voltage is 10-14 volts, go to next test listed in SYMPTOM DIAGNOSIS  table under TROUBLE SHOOTING.
  2. Using an ohmmeter, measure resistance by backprobing rear of 18-pin ECU connector T10 between terminal No. 8 (Blue/Red wire) and ground. If resistance is one ohm or less, go to next step. If resistance is greater than one ohm, repair or replace wiring harness or connector between tilt and telescopic ECU and ground connection. See WIRING DIAGRAMS .
  3. Check continuity of DOME fuse (10-amp) located in engine compartment relay block, forward of left strut tower. If continuity does not exist, check and repair short in wiring harness between DOME fuse and all components connected to fuse. See WIRING DIAGRAMS . If continuity exists, check for open in wiring harness between tilt and telescopic ECU and battery. Repair or replace as necessary and retest system operation.
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