52B-1
GROUP 52B
SUPPLEMENTAL
RESTRAINT
SYSTEM (SRS)
CONTENTS
GENERAL DESCRIPTION. . . . . . . . . 52B-2 SRS-ECU . . . . . . . . . . . . . . . . . . . . . . 52B-10
SYSTEM OPERATION. . . . . . . . . . . . 52B-7
52B-2 SUPPLEMENTAL RESTRAINT SYSTEM (SRS)
GENERAL DESCRIPTION
GENERAL DESCRIPTION
M2521000100132
CAUTION
• Driver and front passenger air bags and seat belt pre-tensioners deploy and operate in all head-on
collisions that exceed the threshold to activate the SRS system.
• The specific value is the equivalent impact when a vehicle collides against a concrete (fixed) wall
at approximately 25 km/h (16 mph) or more.
• The SRS and pre-tensioner may not work under the following conditions:
• A head-on collision is less than the specific value.
• A vehicle collides on its rear end.
• A vehicle rolls over or is in a similar position.
DRIVER'S AIR BAG
PASSENGER'S
SEAT BELT PRE-TENSIONER (FRONT) AIR BAG
AC211587AB
Driver’s and front passenger’s air bags and seat
.
SEAT BELT WITH PRE-TENSIONER
belts with pre-tensioner are standard, increasing the The seat belts with pre-tensioner work simulta-
passive safety level. neously with the SRS. The pre-tensioner takes up
.
SUPPLEMENTAL RESTRAINT SYSTEM (SRS) seat belt slack immediately when a collision takes
The SRS is designed to supplement the front seat place by that restraining the front passengers sooner
belts. It eliminates or reduces or injury to the front than the SRS. This prevents the passengers from
passenger(s) by deploying air bag(s) in case of a moving forwards.
head-on collision.
SUPPLEMENTAL RESTRAINT SYSTEM (SRS)
GENERAL DESCRIPTION
52B-3
CONSTRUCTION DIAGRAM
VEHICLES
IDENTIFICATION
CODE CHART
PLATE
SRS WARNING LIGHT
RADIATOR
DRIVER'S AIR
BAG MODULE
PASSENGER'S (FRONT)
AIR BAG MODULE
FRONT IMPACT SENSOR
CLOCK SPRING
DATA LINK
CONNECTOR
SEAT BELT WITH
(FOR SCAN
SRS-ECU PRE-TENSIONER
TOOL)
AC211592 AB
The SRS and seat belt tightening systems consist of The SRS-ECU detects the impact produced at the
driver’s/passenger air bag modules, SRS-ECU, two time of a collision from the safing and analog G sen-
front impact sensors, SRS warning light, clock sors and supplies squib ignition current to the air bag
spring, and seat belt pre-tensioner. Air bags are modules.
located in the center of the steering wheel and above The SRS-ECU has the following functions:
the glove box. Each air bag has a safing folded air This triggers the air bag modules.
bag and an inflators the system and has a safing G • Power supply backup function (backup con-
sensor and an analogue G sensor. On all air bag denser) that deploys or operates the air bag mod-
modules, the inflator does not contain sodium azide. ule and seat belt pretensioner within specific
The front impact sensor is assembled on the head- period, in case of power failure upon impact.
light support panel to monitor collision upon frontal • Voltage raising function (DC-DC converter cir-
impact. The warning light on the instrument panel cuit).
indicates the operational status of the SRS. A clock • Diagnostic test mode to improve safety and reli-
spring is installed in the steering column. ability.
52B-4 SUPPLEMENTAL RESTRAINT SYSTEM (SRS)
GENERAL DESCRIPTION
SRS SYSTEM CIRCUIT DIAGRAM
IGNITION SWITCH (IG1)
No.2 No.3
7.5A 7.5A POWER
BACK UP DC-DC SOURCE
CAPACITOR CONVERTER CIRCUIT FOR
SIDE-AIRBAG
COMBINATION
METER (SRS
OFF
WARNING LIGHT)
WARNING
ON LIGHT
CONNECTOR LOCK FRONT AIR BAG DRIVE
SAFING SCAN TOOL
SWITCH* OFF CIRCUIT
G-SENSOR INTERFACE
CIRCUIT
DRIVER'S DATA LINK
ON CONNECTOR
AIR BAG
OFF (FOR SCAN
MODULE CONNCTOR LOCK
OFF AIR BAG
SWITCH* TOOL)
DRIVE
ON CONNECTOR
OFF ON CIRCUIT LOCK OFF
OFF AIR BAG DETECTION
PASSENGER'S ON DRIVE CIRCUIT ON
ON
(FRONT) AIR BAG
OFF CLOCK SPRING AIR BAG CIRCUIT
MODULE
DRIVE
ON CONNECTOR CIRCUIT
OFF
LOCK SWITCH* AIR BAG CONNECTOR
DRIVE LOCK OFF
SEAT BELT ON MICRO DETECTION
PRE-TENSIONER OFF CIRCUIT CIRCUIT
AIR BAG PROCESSOR ON
(LH)
DRIVE
ON CONNECTOR CONNECTOR
CIRCUIT LOCK SWITCH*
OFF
LOCK SWITCH*
AIR BAG
SEAT BELT ON DRIVE
PRE-TENSIONER OFF CIRCUIT
(RH) AIR BAG
DRIVE
ON CONNECTOR CIRCUIT
OFF
LOCK SWITCH*
AIR BAG FRONT AIR
DRIVE BAG
CIRCUIT ANALOG
G-SENSOR
FRONT
IMPACT
SENSOR
INTERFACE
CIRCUIT
(LH) (RH)
FRONT IMPACT
SENSOR
NOTE
*: CONNECTOR LOCKED: ON
CONNECTOR UNLOCKED: OFF AC211582 AB
SUPPLEMENTAL RESTRAINT SYSTEM (SRS)
GENERAL DESCRIPTION
52B-5
CAUTION LABELS
Labels to indicate cautions regarding the handling
and the services of SRS air bag air attached on the
position shown in the following illustration.
COVER CLOCK SPRING
PASSENGER'S (FRONT) SRS-ECU SUN VISOR
AIR BAG MODULE
D E
SEAT BELT WITH
PRE-TENSIONER
GLOVE BOX STEERING JOINT COVER (DRIVER'S AND FRONT
PASSENGER'S SEATBELT)
G I
FRONT IMPACT SENSOR
AC211604AB
52B-6 SUPPLEMENTAL RESTRAINT SYSTEM (SRS)
GENERAL DESCRIPTION
LABEL CONTENTS
A WARNING: SRS
BEFORE REPLACING STEERING WHEEL, READ SERVICE MANUAL. THIS AIR BAG
MODULE CANNOT BE REPAIRED.
DO NOT DISASSEMBLE OR TAMPER.
B CAUTION: SRS CLOCK SPRING
THIS IS NOT A REPAIRABLE PART. IF DEFECTIVE, REPLACE ENTIRE UNIT
ACCORDING TO THE SERVICE MANUAL INSTRUCTIONS. TO RE-CENTER: ROTATE
CLOCKWISE UNTIL TIGHT. THEN ROTATE IN OPPOSITE DIRECTION ROUGHLY 3
TURNS AND ALIGN ARROWS >><<.
C WARNING FLAMMABLE/EXPLOSIVE SRS AIR BAG MODULE
TO AVOID SERIOUS INJURY:
• DO NOT REPAIR, DISASSEMBLE OR TAMPER.
• AVOID CONTACT WITH FLAME OR ELECTRICITY.
• DO NOT DIAGNOSIS/USE NO TEST EQUIPMENT OR PROBES.
• STORE BELOW 200°F (93°C).
• BEFORE DOING ANY WORK INVOLVING MODULE, READ SERVICE MANUAL
FOR IMPORTANT FURTHER DATA.
D CAUTION:
DO NOT DISASSEMBLE OR DROP. IF DEFECT REFER TO SERVICE MANUAL.
E WARNING
DEATH or SERIOUS INJURY can occur
• Children 12 and under can be killed by the air bag.
• The BACK SEAT is the SAFEST place for children.
• NEVER put a rear-facing child seat in the front.
• Sit as far back as possible from the air bag.
• ALWAYS use SEAT BELTS and CHILD RESTRAINTS.
F AIR BAG SYSTEM INFORMATION
THIS VEHICLE HAS AN AIR BAG SYSTEM WHICH WILL SUPPLEMENT THE SEAT
BELT IN CERTAIN FRONTAL COLLISIONS. THE AIR BAG IS NOT A SUBSTITUTE FOR
THE SEAT BELT IN ANY TYPE OF COLLISION. THE DRIVER AND ALL OTHER
OCCUPANTS SHOULD WEAR SEAT BELTS AT ALL TIME.
WARNING!
IF THE "SRS" WARNING LIGHT DOES NOT ILLUMINATE FOR SEVERAL SECONDS
WHEN IGNITION KEY IS TURNED TO "ON" OR THE ENGINE IS STARTED, OR IF THE
WARNING LIGHT STAYS ON WHILE DRIVING, TAKE THE VEHICLE TO YOUR
NEAREST AUTHORIZED DEALER IMMEDIATELY. ALSO, IF VEHICLE'S FRONT END
IS DAMAGED OR IF THE AIR BAG HAS DEPLOYED, TAKE THE VEHICLE FOR
SERVICE IMMEDIATELY.
THE AIR BAG SYSTEM MUST BE INSPECTED BY AN AUTHORIZED DEALER TEN
YEARS AFTER THE VEHICLE MANUFACTURE DATE SHOWN ON THE
CERTIFICATION LABEL LOCATED ON THE LEFT FRONT DOOR-LATCH POST OR
DOOR FRAME.
READ THE "SRS" SECTION OF YOUR OWNER'S MANUAL BEFORE DRIVING FOR
IMPORTANT INFORMATION ABOUT OPERATION AND SERVICE OF THE AIR BAG
SYSTEM.
WHEN YOU ARE GOING TO DISCARD YOUR GAS GENERATOR OR VEHICLE,
PLEASE SEE YOUR DEALER.
SUPPLEMENTAL RESTRAINT SYSTEM (SRS)
SYSTEM OPERATION
52B-7
LABEL CONTENTS
G WARNING
CHILDREN CAN BE KILLED OR INJURED BY PASSENGER AIR BAG. THE BACK
SEAT IS THE SAFEST PLACE FOR CHILDREN 12 AND UNDER. MAKE SURE ALL
CHILDREN USE SEAT BELTS OR CHILD SEAT. NOT TO BE REMOVED EXCEPT BY
OWNER.
H CAUTION: SRS
FIX STRG. WHEEL AT TIRES STRAIGHT AHEAD BEFORE GEARBOX REMOVAL.
OTHERWISE, MAY DAMAGE SRS CLOCK SPRING MAKING SRS SYSTEM IN
OPERATIVE. RISKING SERIOUS DRIVER INJURY.
I DANGER SEAT BELT PRETENSIONER
CAUTION THIS ASSEMBLY CONTAINS AN EXPLOSIVE INITIATOR
FLAMMABLE MATERIAL
TO PREVENT PERSONAL INJURY
• DO NOT IMPACT, DISMANTLE OR INSTALL IT INTO ANOTHER VEHICLE.
• SERVICE OR DISPOSE OF IT AS DIRECTED IN THE REPAIR MANUAL.
J CAUTION:
DO NOT DISASSEMBLE OR DROP.
SYSTEM OPERATION
M2521001000116
A passenger’s (front) air bag module and clock
spring are the same as OUTLANDER.
DRIVER’S AIR BAG MODULE
SECTION A - A
A AIR BAG MODULE
INFLATOR
MODULE COVER
AIR BAG
A AC211615AB
CAUTION nylon and inflates by the gas generating from the
Never disassemble the air bag module. inflator. As a driver is being pressed to the air bag, it
The driver’s air bag module is incorporated into the deflates discharging gas from two vents at the rear of
3-spoke steering wheel. The driver’s air bag module the air bag to reduce the shock from the impact. An
is an assembly part consisting of air bag, module inflator that does not contain sodium azide is used.
cover, inflator, and its their fasteners. It is installed
into the steering wheel. The air bag is made from
52B-8 SUPPLEMENTAL RESTRAINT SYSTEM (SRS)
SYSTEM OPERATION
FRONT IMPACT SENSOR
CAUTION
Never disassemble the front impact sensor.
SENSOR INTERNAL CIRCUIT The front impact sensor is installed in the radiator support
panel. In a collision, the contact in the front impact sensor turns
ON and an output signal is send to the SRS-ECU. A resistor is
connected to the front impact sensor in parallel with the contact
for fault diagnosis.
AC206958AC
SEAT BELT WITH PRE-TENSIONER
RING GEAR
BALL
PINION
SPOOL
PIPE
GAS GENERANT AC101663AE
CAUTION Upon front impact the pretensioner ignites the gas
Never disassemble the seat belt with pre-ten- generator and emits gas with the SRS-ECU signal
sioner. when the front impact sensor, attached to the front of
The seatbelt incorporating the pretensioner automat- the body, detects an impact that exceeds the permis-
ically winds the seatbelt upon front impact to reduce sible limit. The gas pressure shifts the ball in the pipe
forward shifting of the passenger. and the balls comes in contact with the protrusion of
The seat belt pre-tensioner is built into the driver's the ring gear, The ball is inserted in the ring gear and
and passenger's front seat belt retractor. then interlocked with the pinion. The ring gear rota-
tion forces the pinion to turn the spool toward the belt
wind direction to wind the webbing.
SUPPLEMENTAL RESTRAINT SYSTEM (SRS)
SYSTEM OPERATION
52B-9
SRS AIR BAG SPECIAL CONNECTOR
A
SEAT BELT WITH
PRE-TENSIONER
A (DRIVER'S SIDE)
CLOCK
SPRING
DRIVER'S AIR BAG MODULE
SRS-ECU
PASSENGER'S (FRONT)
AIR BAG MODULE
SEAT BELT WITH
A PRE-TENSIONER
(FRONT PASSENGER'S
A SIDE) AC103223 AF
To enhance the System’s reliability, a connector lock
switch is integrated into the SRS-ECU connector, the
air bag module connectors, the clock spring connec-
tor, the seat belt pretensioner connectors (black con-
nector "A" shown in the illustration above).
SQUIB CIRCUIT CONNECTOR LOCK SWITCH
CONNECTOR CONNECTED CONNECTOR DISCONNECTED
OFF OFF
ON
ON
SQUIB SQUIB
SRS-ECU SRS-ECU
OFF OFF
ON ON
<CONNECTOR SHORTING MECHANISM (E.G. SRS-ECU CONNECTOR)>
ECU-SIDE CONNECTOR WIRING HARNESS-SIDE CONNECTOR
A B
TERMINAL
TERMINAL (FEMALE)
(MALE)
CONNECTOR CONNECTED
PARTITION
PANEL
A B TERMINAL
SHORT SPRING
(FEMALE)
SECTION A - A SECTION B - B TERMINAL
(MALE)
TERMINAL TERMINAL
PARTITION
(MALE) (FEMALE)
PANEL
PARTITION
SHORT SHORT SPRING
PANEL
SPRING
AC006197AH
52B-10 SUPPLEMENTAL RESTRAINT SYSTEM (SRS)
SRS-ECU
CAUTION The switch is a mechanism that shorts the power
When the connector is disconnected, there will supply terminal to the ground terminal automatically
be short circuit between the terminals. This is not in the air bag squib circuit when the connector is dis-
a fault. connected. A "short" spring is integrated inside the
connector. This spring prevents static electricity from
flowing to the squib by shorting the power supply ter-
minal to the ground terminal (i.e. there is no potential
difference between the two terminals).
WARNING LIGHT CIRCUIT CONNECTOR LOCK
SWITCH
The switch is a mechanism that shorts the power supply termi-
IGNITION nal to the ground terminal automatically in the warning light cir-
SWITCH (IG1) cuit, when the connector is disconnected. Its structure is similar
to the squib circuit connector shorting mechanism.
SRS WARNING
LIGHT
SRS-ECU HARNESS-SIDE
CONNECTOR
ON
CONNECTOR OFF
LOCK SWITCH* ON
SHORT
SPRING OFF
NOTE
*: CONNECTOR LOCKED: ON
CONNECTOR UNLOCKED: OFF AC006203 AB
SRS-ECU
M2521007000095
CAUTION The SRS-ECU is provided with the following capabil-
Never disassemble the SRS-ECU. ities:
The SRS-ECU incorporates an analog G-sensor and • Backup power supply in case of power failure in
safing G-sensor for frontal collisions and a safing G- collisions
sensor for side collisions. In frontal collisions, the • Boosting function in case of battery voltage drop
driver’s and passenger’s (front) air bags deploy and • Self-diagnosis function to avoid system’s opera-
the seat belt pre-tensioners are activated only when tion errors and improve its reliability
both the analog and safing G-sensors detect simulta-
neously a collision-induced G of a level exceeding DIAGNOSTIC FUNCTION
the threshold as in the case with the conventional The SRS-ECU has the following functions to make
system. In the case of side collisions, the side-airbag system checking using the scan tool easy.
on the side subjected to an impact deploys if the side • Diagnostic trouble code output
impact sensor and the SRS-ECU’s safing G-sensor • Service data output
detect simultaneously a lateral G of forces above the
predetermined level.
SUPPLEMENTAL RESTRAINT SYSTEM (SRS)
SRS-ECU
52B-11
DIAGNOSTIC TROUBLE CODE OUTPUT
The SRS-ECU diagnoses the following items and
stores a diagnostic trouble code in the non-volatile
memory (EEPROM*1) when a problem is detected.
Therefore, the memory is not deleted after a battery
terminal is disconnected, (The diagnostic trouble
code memory can be deleted by the scan tool.)
CODE NO. MAJOR CONTENTS OF DIAGNOSTICS
1A Front impact sensor (LH) short-circuited
1B Front impact sensor (LH) open-circuited
1C Front impact sensor (LH) short-circuited to power supply
1D Front impact sensor (LH) short-circuited to ground
2A Front impact sensor (RH) short-circuited
2B Front impact sensor (RH) open-circuited
2C Front impact sensor (RH) short-circuited to power supply
2D Front impact sensor (RH) short-circuited to ground
14 Analog G-sensor malfunction
15 Safing G-sensor short-circuited (for frontal collision)
16 Safing G-sensor open-circuited (for frontal collision)
21*3 Driver's air bag squib short-circuited
22*3 Driver's air bag squib open-circuited
24*3 Passenger's (front) air bag squib short-circuited
25*3 Passenger's (front) air bag squib open-circuited
26*3 Driver's pre-tensioner squib short-circuited
27*3 Driver's pre-tensioner squib open-circuited
28*3 Passenger's (front) pre-tensioner squib short-circuited
29*3 Passenger's (front) pre-tensioner squib open-circuited
31 SRS-ECU capacitor circuit voltage too high
32 SRS-ECU capacitor circuit voltage too low
34*2 SRS-ECU connector lock out of order
35 Ignition of the air bag completed
39 Air bag deployed simultaneously
41*2 Power supply voltage (IG1 (A) voltage) drops a0bnormally.
42*2 Power supply voltage (IG1 (B) voltage) drops abnormally.
43*2 SRS warning light circuit open-circuited
44*2 SRS warning light circuit malfunction
45 SRS-ECU non-volatile memory (EEPROM) and A/D converter system
46*2 Incorrect SRS-ECU
51 Driver's air bag squib activating circuit short-circuited
52 Driver's air bag squib activating circuit open-circuited
52B-12 SUPPLEMENTAL RESTRAINT SYSTEM (SRS)
SRS-ECU
CODE NO. MAJOR CONTENTS OF DIAGNOSTICS
54 Passenger's (front) air bag squib activating circuit short-circuited
55 Passenger's (front) air bag squib activating circuit open-circuited
56 Driver’s seat belt pre-tensioner (squib ignition drive circuit) system detected short
57 Driver’s seat belt pre-tensioner (squib ignition drive circuit) system detected open
58 Passenger’s seat belt pre-tensioner (squib ignition drive circuit) system detected
short
59 Passenger’s seat belt pre-tensioner (squib ignition drive circuit) system detected
open
61 Driver's air bag squib drive circuit (power supply side) short-circuited
62 Driver's air bag squib drive circuit (ground side) short-circuited
64 Passenger's (front) air bag squib drive circuit (power supply side) short-circuited
65 Passenger's (front) air bag squib drive circuit (ground side) short-circuited
66 Driver's pre-tensioner squib (power supply side) short-circuited
67 Driver's pre-tensioner squib (ground side) short-circuited
68 Passenger's (front) pre-tensioner squib drive circuit (power supply side) short-
circuited
69 Passenger's (front) pre-tensioner squib drive circuit (ground side) short-circuited
NOTE: *1 : Electrically Erasable Programmable ROM
*2: This diagnostic trouble code memory will be automatically cleared from the memory and the SRS warning
light will be switched off when the system returns to normal condition.
*3: The diagnostic trouble codes will remain in memory and the SRS warning light will be switched off if the
system returns to normal condition.
DATA LIST OUTPUT
When the SRS-ECU detects a problem, it stores a
diagnostic trouble code and the duration that the
problem has lasted in the non-voltage memory. In
addition, how often a diagnostic trouble code and
duration are cleared by the scan tool are stored in
the non-volatile memory as a reference for service
work. This data can be read by the scan tool.
No. DATA LIST ITEM APPLICABILITY
92 Number indicating how often the memory is cleared Maximum time to be stored: 250
days
93 How long a problem has lasted (How long from the Maximum time to be stored: 9999
occurrence of the problem until the first air bag squib minutes (approximately seven
ignition signal) days)
94 How long a problem has lasted (How long from the first
air bag squib igniting signal until now)
