LEMON Manuals: Even more car manuals for everyone: 1960-2025
Home >> Lexus >> 1998 >> GS 400 >> Repair and Diagnosis >> Body & Frame >> Body, Cab Control Systems >> Body Control System >> Circuit Tests >> Power Source Circuit No. 2
April 5, 2026: LEMON Manuals is launched! Read the announcement.

Power Source Circuit No. 2

NOTE: Body control ECU No. 2 is plugged into driver-side junction block. To check voltages, it is necessary to probe wiring going into junction block. See Fig 1.

  1. Check Fuses

    Check condition of MPX-B and GAUGE fuse. See FUSE LOCATIONS table. If fuses are okay, go to next step. If fuse(s) are not okay, replace appropriate fuse and retest system operation.
  2. Check For Voltage

    Turn ignition on. Using a voltmeter, check voltage between Black/Yellow wire (IG) and White/Black wire (GND) leading into junction block. See Fig 1. Check voltage between Green/White wire (BECU) and White/Black wire (GND) leading into junction block. If voltages are not 10-14 volts, go to next step. If voltages are 10-14 volts, go to next test listed in appropriate TROUBLE SHOOTING SYMPTOMS table.
  3. Check Circuits

    Check circuits for faults between ground and body control ECU No. 2. See WIRING DIAGRAMS. Repair or replace as necessary. If circuits are okay, check and repair circuits between body control ECU No. 2 and battery. Retest system operation.
Fig 1: Identifying Driver-Side Junction Block
G98H04737Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002