Mitsubishi Galant. Manual - part 604
SRS AIR BAG DIAGNOSIS
TSB Revision
SUPPLEMENTAL RESTRAINT SYSTEM(SRS)
52B-57
CIRCUIT OPERATION
•
The SRS-ECU is powered from the ignition
switch (IG1).
•
The SRS-ECU power is supplied from two
circuits. Even if one circuit is shut off, the air bag
can inflate.
•
The SRS system diagnosis can be done by
connecting scan tool MB991502 to the data link
connector.
•
The SRS-ECU judges how severe a collision is
by detecting signals from the left and right side
impact sensors and the analog G-sensor. If the
impact is over a predetermined level, the SRS-
ECU outputs an ignition signal. At this time, if the
safing G-sensor is on, the SRS air bag will inflate.
TECHNICAL DESCRIPTION (COMMENT)
•
If communication is not possible with the SRS
only, the cause is probably an open circuit in the
on-board diagnostic output circuit of the SRS or
in the power circuit (including ground circuit).
TROUBLESHOOTING HINTS
•
Damaged wiring harnesses or connectors
•
Malfunction of the SRS-ECU
DIAGNOSIS
STEP 1. Check the ground line at the SRS-ECU connector
C-44 by backprobing.
(1)Do disconnect the connector C-44.
(2)Check the continuity between terminal 3 and the ground by
backprobing.
Q: Is the resistance between terminal 3 and ground less
than 2 ohm?
YES : Go to Step 3.
NO : Go to Step 2.
AC003195AB
CONNECTOR: C-44
SRS-ECU
CENTER
REINFORCEMENT
AC003201AB
CONNECTOR: C-73, C-77
JUNCTION BLOCK (REAR)
C-73
C-77
AC003213AB
CONNECTOR: C-23
AC000368AD
C-44 CONNECTOR HARNESS SIDE VIEW