Pre-Collision System

PRE-COLLISION: PRE-COLLISION SYSTEM: Power Source Circuit

Power Source Circuit

DESCRIPTION

This circuit supplies power to the seat belt control ECU.

WIRING DIAGRAM





INSPECTION PROCEDURE
NOTE:
When the seat belt control ECU is replaced with a new one, INITIALIZATION must be performed Pre-Collision System.

PROCEDURE

1. INSPECT SEAT BELT CONTROL ECU (+B TERMINAL VOLTAGE)




(a) Disconnect the negative (-) battery terminal.
CAUTION:
Wait at least 90 seconds after disconnecting the cable from the negative (-) battery terminal to disable the SRS system.
(b) Disconnect the Q58connector of the seat belt control ECU.
(c) Connect the negative (-) battery terminal.
(d) Measure the voltage according to the value(s) in the table below.
Standard voltage:





(e) Disconnect the negative (-) battery terminal.
(f) Reconnect the Q58 connector of the seat belt control ECU.
(g) Connect the negative (-) battery terminal.
NG -- INSPECT FUSE (PSB FUSE)
OK -- Continue to next step.
2. INSPECT SEAT BELT CONTROL ECU (IG1 TERMINAL VOLTAGE)




(a) Disconnect the negative (-) battery terminal.
CAUTION:
Wait at least 90 seconds after disconnecting the cable from the negative (-) battery terminal to disable the SRS system.
(b) Disconnect the Q59 connector of the seat belt control ECU.
(c) Connect the negative (-) battery terminal.
(d) Measure the voltage according to the value(s) in the table below.
Standard voltage:





(e) Disconnect the negative (-) battery terminal.
(f) Reconnect the Q59 connector of the seat belt control ECU.
(g) Connect the negative (-) battery terminal.
NG -- INSPECT FUSE (ECU-IG RH FUSE)
OK -- Continue to next step.
3. INSPECT SEAT BELT CONTROL ECU (PGND CIRCUIT)




(a) Disconnect the negative (-) battery terminal.
CAUTION:
Wait at least 90 seconds after disconnecting the cable from the negative (-) battery terminal to disable the SRS system.
(b) Disconnect the Q58 connector of the seat belt control ECU.
(c) Measure the resistance according to the value(s) in the table below.
Standard resistance:





(d) Reconnect the Q58 connector of the seat belt control ECU.
(e) Connect the negative (-) battery terminal.
NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR (PGND CIRCUIT)
OK -- PROCEED TO NEXT SUSPECTED AREA SHOWN IN PROBLEM SYMPTOMS TABLE
4. INSPECT FUSE (PSB FUSE)




(a) Remove the PSB fuse from the cowl side J/B LH.
(b) Measure the resistance according to the value(s) in the table below.
Standard resistance:





(c) Reinstall the PSB fuse to the cowl side J/B LH.
NG -- REPLACE FUSE (PSB FUSE)
OK -- REPAIR OR REPLACE HARNESS OR CONNECTOR (SEAT BELT CONTROL ECU - BATTERY)
5. INSPECT FUSE (ECU-IG RH FUSE)




(a) Remove the ECU-IG RH fuse from the cowl side J/B RH.
(b) Measure the resistance according to the value(s) in the table below.
Standard resistance:





(c) Reinstall the ECU-IG RH fuse to the cowl side J/B RH.
NG -- REPLACE FUSE (ECU-IG RH FUSE)
OK -- REPAIR OR REPLACE HARNESS OR CONNECTOR (SEAT BELT CONTROL ECU - RH-IG1 RELAY)