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 Q57 new one, Initialization must be performed Pre-Collision System.

PROCEDURE

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




(a) Disconnect the negative (-) terminal cable from the battery.
CAUTION:
Wait at least 90 seconds after disconnecting the cable from the negative (-) battery terminal to disable the SRS system.
(b) Disconnect the Q57 seat belt control ECU connector.
(c) Connect the negative (-) terminal cable to the battery.
(d) Measure the voltage according to the value(s) in the table below.
Standard voltage:





(e) Disconnect the negative (-) terminal cable from the battery.
(f) Reconnect the Q57 seat belt control ECU connector.
(g) Connect the negative (-) terminal cable to the battery.
NG -- INSPECT FUSE (SPB FUSE)
OK -- Continue to next step.

2. INSPECT SEAT BELT CONTROL ECU (IG1 TERMINAL VOLTAGE)




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





(e) Disconnect the negative (-) terminal cable from the battery.
(f) Reconnect the Q58 seat belt control ECU connector.
(g) Connect the negative (-) terminal cable to the battery.
NG -- INSPECT FUSE (ECU-IG RH FUSE)
OK -- Continue to next step.

3. INSPECT SEAT BELT CONTROL ECU (PGND CIRCUIT)




(a) Disconnect the negative (-) terminal cable from the battery.
CAUTION:
Wait at least 90 seconds after disconnecting the cable from the negative (-) battery terminal to disable the SRS system.
(b) Disconnect the Q57 seat belt control ECU connector.
(c) Measure the resistance according to the value(s) in the table below.
Standard resistance:





(d) Reconnect the Q57 seat belt control ECU connector.
(e) Connect the negative (-) terminal cable to the battery.
NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR (PGND CIRCUIT)
OK -- PROCEED TO NEXT SUSPECTED AREA SHOWN IN PROBLEM SYMPTOMS TABLE
4. INSPECT FUSE (SPB 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)