RX400h · Service Manual SECURITIES

ECU Power Source Circuit

Circuit diagnosis

DESCRIPTION

This circuit provides power to the transponder key ECU.

WIRING DIAGRAM

B111577E02
B111830E02

INSPECTION PROCEDURE


1. CHECK FUSES (MPX-B, IGN, AM2 No.1)

  1. Remove the MPX-B, IGN fuses from the instrument panel J/B.

  1. Remove the AM2 No.1 (LHD, RHD) and AM2 No.2 (RHD) fuses from the fusible link block.

  1. Measure the resistance of the fuse(s).

    Resistance:
    Below 1 Ω



 NG
CHECK FOR SHORT IN ALL HARNESS AND CONNECTOR CONNECTED TO FUSE AND REPLACE FUSE
OK


2. CHECK HARNESS AND CONNECTOR (TRANSPONDER KEY ECU ASSEMBLY - BATTERY)

  1. B111587E15
    Disconnect T8 ECU connector.

  1. Measure the voltage according to the value(s) in the table below.

    Voltage:
    Tester Connection
    		 Condition
    		 Specified Condition
    T8-2 (IG2) - Body ground
    		 Ignition switch off
    		 Below 1 V
    T8-2 (IG2) - Body ground
    		 Ignition switch on
    		 10 to 14 V
    T8-1 (CPUB) - Body ground
    		 Always
    		 0 to 14 V



NG
REPAIR OR REPLACE HARNESS OR CONNECTOR
OK


3. CHECK HARNESS AND CONNECTOR (TRANSPONDER KEY ECU ASSEMBLY - BODY GROUND)

  1. B111587E14
    Measure the resistance according to the value(s) in the table below.

    Resistance:
    Tester Connection
    		 Condition
    		 Specified Condition
    T8-14 (GND) - Body ground
    		 Always
    		 Below 1 Ω



NG
REPAIR OR REPLACE HARNESS OR CONNECTOR
OK

PROCEED TO NEXT CIRCUIT INSPECTION SHOWN IN PROBLEM SYMPTOMS TABLE


← B2799-542PRECAUTION →