Component Tests and General Diagnostics

CELLULAR COMMUNICATION: LEXUS LINK SYSTEM: ECU Power Source Circuit

ECU Power Source Circuit

DESCRIPTION

This circuit supplies power to operate the mayday ECU assembly.

WIRING DIAGRAM





INSPECTION PROCEDURE

PROCEDURE

1. INSPECT FUSE (MAYDAY, GAUGE, AM2, ACC)
(a) Remove the MAYDAY and AM2 fuses from the engine room junction block.
(b) Remove the ACC and GAUGE fuses from the driver side junction block.
(c) Measure the resistance of the fuses.
Standard resistance:
Below 1 Ohms
NG -- REPLACE FUSE
OK -- Continue to next step.
2. INSPECT RELAY (ACC CUT RELAY)




(a) Remove the ACC CUT relay from the engine room relay block.
(b) Measure the resistance of the relay.
Standard resistance:






NG -- REPLACE RELAY
OK -- Continue to next step.
3. CHECK WIRE HARNESS (ECU - BATTERY AND BODY GROUND)




(a) Disconnect the M15 ECU connector.
(b) Measure the voltage and resistance of the wire harness side connector.
Standard voltage:






Standard resistance:





NOTE:
If replacement of the ECU is necessary, replace the mayday battery (backup battery) together with the ECU. After the replacement, register the ECU Programming and Relearning.

NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR
OK -- REPLACE MAYDAY ECU ASSEMBLY