Toyota AT180 Series Repair Manual page 155

SYSTEM OUTLINE
THE SRS (SUPPLEMENTAL RESTRAINT SYSTEM) AIRBAG IS A DRIVER PROTECTION DEVICE WHICH HAS A SUPPLEMENTAL ROLE
TO THE SEAT BELTS.
CURRENT FLOWS CONSTANTLY TO TERMINAL 6 OF THE CENTER AIRBAG SENSOR ASSEMBLY. WHEN THE IGNITION SW IS
TURNED TO ACC OR ON, CURRENT FROM THE CIG & RAD FUSE FLOW TO TERMINAL 14 OF THE CENTER AIRBAG SENSOR
ASSEMBLY. ONLY WHEN THE IGNITION SW IS ON DOES THE CURRENT FROM THE ECU–IG FUSE FLOW TO TERMINAL 1, AND THE
CURRENT FROM THE IGN FUSE TO TERMINAL 7.
IF AN ACCIDENT OCCURS WHILE DRIVING, DECELERATION CAUSED BY A FRONTAL IMPACT IS DETECTED BY EACH SENSOR AND
SWITCH, AND WHEN THE FRONTAL IMPACT EXCEEDS A SET LEVEL (WHEN THE MERCURY SW BUILT INTO THE CENTER AIRBAG
SENSOR ASSEMBLY IS ON AND THE CENTER AIRBAG SENSOR IS ON, FRONT AIRBAG SENSORS ARE OFF), CURRENT FROM THE
CIG & RAD, ECU–IG OR IGN FUSE FLOWS TO TERMINAL 11 OF THE CENTER AIRBAG SENSOR ASSEMBLY
AIRBAG SQUIB SQUIB
BODY GROUND GROUND.
WHEN THE MERCURY SW BUILT INTO THE CENTER AIRBAG SENSOR ASSEMBLY IS ON AND THE FRONT AIRBAG SENSOR LH OR
RH IS ON, CENTER AIRBAG SENSOR IS OFF CURRENT FROM THE CIG & RAD, ECU–IG OR IGN FUSE FLOWS TO TERMINAL 11 OF
THE CENTER AIRBAG SENSOR ASSEMBLY
CENTER AIRBAG SENSOR ASSEMBLY
TERMINAL 2 OR 5 OF CENTER AIRBAG SENSOR ASSEMBLY
WHEN THE MERCURY SW BUILT INTO THE CENTER AIRBAG SENSOR ASSEMBLY IS ON, AND THE FRONT AIRBAG SENSOR LH OR
RH IS ON AND CENTER AIRBAG SENSOR IS ON ONE OF THE ABOVE–MENTIONED CIRCUITS IS ACTIVATED SO THAT CURRENT
FLOWS TO THE AIRBAG SQUIB AND CAUSES IT TO OPERATE. THE BAG STORED INSIDE THE STEERING WHEEL PAD IS
INSTANTANEOUSLY EXPANDED TO SOFTEN THE SHOCK TO THE DRIVER.
THE REASON WHY THERE ARE MULTIPLE POWER SOURCES AND GROUND POINTS IS SO THAT IN THE EVENT THAT ONE OR TWO
OF THE POWER SOURCES AND GROUND POINTS DO NOT WORK FOR SOME REASON, THE REMAINING POWER SOURCE AND
GROUND POINT WILL BE AVAILABLE TO COMPENSATE.
: PARTS LOCATION
CODE SEE PAGE
A28 28
C 1 26 (5S–FE), 27 (4A–FE)
: RELAY BLOCKS
CODE SEE PAGE
4 24
: JUNCTION BLOCK AND WIRE HARNESS CONNECTOR
CODE SEE PAGE
1C 18
: CONNECTOR JOINING WIRE HARNESS AND WIRE HARNESS
CODE SEE PAGE
IG2 36
: GROUND POINTS
CODE SEE PAGE
IE 36
IG 36
: SPLICE POINTS
CODE SEE PAGE
I 4 36
TERMINAL 2 TERMINAL 10 OF CENTER AIRBAG SENSOR ASSEMBLY
TERMINAL 1 OF THE AIRBAG SQUIB
TERMINAL 3 OR 4
CODE
C 7
C13
RELAY BLOCKS (RELAY BLOCK LOCATION)
R/B NO. 4 (RIGHT KICK PANEL)
JUNCTION BLOCK AND WIRE HARNESS (CONNECTOR LOCATION)
COWL WIRE AND J/B NO. 1 (LEFT KICK PANEL)
JOINING WIRE HARNESS AND WIRE HARNESS (CONNECTOR LOCATION)
ENGINE WIRE AND COWL WIRE (UNDER THE ENGINE ECU)
GROUND POINTS LOCATION
INSTRUMENT PANEL BRACE LH
R/B NO. 4 SET BOLT
WIRE HARNESS WITH SPLICE POINTS
COWL WIRE
SQUIB
TERMINAL 1 OF FRONT AIRBAG SENSOR
TERMINAL 8, TERMINAL 13 OR BODY GROUND
SEE PAGE
28
28
CODE SEE PAGE
TERMINAL 1 OF THE
TERMINAL 8, TERMINAL 13 OR
TERMINAL 2 TERMINAL 10, OF THE
TERMINAL 2
GROUND.
CODE SEE PAGE
F 3 26 (5S–FE), 27 (4A–FE)
F 4 26 (5S–FE), 27 (4A–FE)
WIRE HARNESS WITH SPLICE POINTS
165