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Ecu Power Source Circuit No. 1

NOTE: Body control ECU No. 1 is plugged into passenger-side junction block. To check voltages, it is necessary to probe wiring going into junction block. See Fig 2.
  1. Check condition of MPX-B, RADIO NO. 2, P FR DOOR, and GAUGE fuses. See FUSE LOCATIONS  table. If fuses are okay, go to next step. If fuse(s) are faulty, replace appropriate fuse and retest system operation.
  2. Turn ignition on. Using a voltmeter, measure voltage between the following ECU No. 1 connector terminals leading into junction block. See Fig 1 and Fig 2 .
    • Terminal No. 15 (ACC) and White/Black wire (GND).
    • Black/Red wire (IG) and White/Black wire (GND).

    If voltages are not 10-14 volts, go to next step. If voltages are 10-14 volts, go to next test listed in appropriate SYMPTOM DIAGNOSIS table under TROUBLE SHOOTING .

  3. Turn ignition off. Disconnect body control ECU No. 1 connector (located behind front passenger right side kick panel). Turn ignition on. Using a voltmeter, measure voltage between the following ECU No. 1 connector terminals leading into junction block. See Fig 1 and Fig 2 .
    • Black wire (BSUB) and White/Black wire (GND).
    • Green/White wire (BECU) and White/Black wire (GND).

    If voltages are not 10-14 volts, go to next step. If voltages are 10-14 volts, go to next test listed in appropriate SYMPTOM DIAGNOSIS table under TROUBLE SHOOTING .

  4. Check circuits for faults between body ground and body control ECU No. 1. See WIRING DIAGRAMS . Repair or replace as necessary. If circuits are okay, check and repair circuits between body control ECU No. 1 and battery. Retest system operation.
FUSE LOCATIONS

Fuse Location
GAUGE (1) Driver-Side Junction Block
MPX-B (2) Engine Compartment Relay Block No. 1
P FR DOOR (3) Passenger-Side Junction Block
RADIO NO. 2 (1) Driver-Side Junction Block
(1) Located behind driver left side kick panel.
(2) Located in right side of engine compartment, behind shock tower.
(3) Located behind front passenger right side kick panel.
Fig 1: Identifying Body Control ECU No. 1 & No. 2 Connector Terminals At Junction Block
G98D04735Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
Fig 2: Identifying Passenger-Side Junction Block Terminals
G98F04736Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002