MITSUBISHI COLT 2006 Service Repair Manual

SYSTEM OPERATION
SUPPLEMENTAL RESTRAINT SYSTEM (SRS)52B-9
SIDE AND CURTAIN AIR BAGS
M2521000800045
AC208121
AC206839
AC207324
Side collision against another vehicleIgnition judgment
SRS-ECU
Shock
above a
certain
level
Ignition signalCurtain air bag modules
Side-airbag modules
Side impact
sensor (RH)
Side impact
sensor (LH)
AC
Ignition signal
Side-airbag safing
G-sensor
In
case of a side co llisio n , if a n imp a ct tha t ba sed on
criteria
is simult ane ously det ect ed b y th e side imp a ct
sensors
inst alled in a centre pillar an d respectively
and by the side
-airba g sa fing G-se nsor (the senso r s
turn ON),
the SRS-ECU sends an ignition signa l to
the side-airbag modu
le an d curt ain air bag module
on the
relevant side to inf l ate them.

SYSTEM CONSTRUCTION
SUPPLEMENTAL RESTRAINT SYSTEM (SRS)52B-10
SYSTEM CONSTRUCTION
DRIVER'S SIDE AIR BAG MODULEM2521002000216
Refer to GROUP 37, Steering wheel P.37-5.
PASSENGER'S (FRONT) AIR BAG MODULE
M2521003000349
AC206612
AC206613
AC207778
AE
A
A
Section A - A
Passenger's (front)
air bag module
Air bag
Inflator
Passeng er ’ s (f ron t ) air ba g mo du le co nsist s o f t h e a i r
bag, inflat
or , and fixing b r acket s .
The air bag is made of nylon an d inf l ated by th e gas
supp
lied from the in flato r . As th e driver ’ s b ody sin ks
into t
he in flated air b ag, the air b ag deflates while dis
-
chargi ng th e gas from two side vent s to abso r b the
imp
a ct.
SIDE-AIRBAG M O DULE
M25210040 0022 3
The sid e -airbag mo dule structure is the sa me as that
for 200
1 P A JERO.

SYSTEM CONSTRUCTION
SUPPLEMENTAL RESTRAINT SYSTEM (SRS)52B-11
CURTAIN AIR BAG MODULE
M2521000500088
AC401546
AC207337AC207332
AC207338
Split hole
Burst disk 2Squib
Propellant
Burst disk 1
Curtain air bag moduleInflator
AB
High-pressure gas
The curt ain air b ag module co nsist s o f an a i r ba g, an
infla
t or , an d the f i xing ge ar rela ting to those p a rt s,
and is in
st alled in the roo f side sections (from t he
driver's an
d the p a sse nger's front p illars to the re ar
pill
ars).
The air bag is made f r om nylon with th e inside
coate
d with silico n, and housed in the roo f side sec
-
tions, folded up comp actly .
The inflato r is of a hybrid type filled wit h hig h -pres-
sure ga s (majo r compone nt: argo n). Whe n curr ent
p
a ss es t h ro ug h t h e sq ui b t o ig ni te th e ig n i t e r po wde r ,
burst
disk 1 b u rst s . T hen, th e co mbustion of the
i
gni ter powder increases the pres sure of the filler gas
to burst disk 2
, lett ing th e gas out o f the split hole.
CURTAIN AIR BAG DEPLOYMENT
IGNITION
AC304629
if an imp a ct in a side collision is de tecte d b y the rear
side
imp a ct senso r inst a lled inside a inn e r quart e r
p
a n e l an d by the side-a i rbag safing G-sen s or inte
-
grated in the SRS-ECU, the SRS-ECU se nds a n igni-
tion signal to th e squib o f th e re levant curt ain a i r bag
mo
du le. Wh en t h is ig nition sign al p a sses t h r o u g h t h e
squib, the
inflator ge nerates gas.
INFLATING
AC304630
The air bag st art s to a ppear p u shing away a he adlin-
ing.
COMPLETION OF INFLATION
AC304631
The air bag fu lly in flates to p r otect the he ads of the
occup
ant s in the fro n t and rear seat s.

SYSTEM CONSTRUCTION
SUPPLEMENTAL RESTRAINT SYSTEM (SRS)52B-12
FRONT IMPACT SENSOR
M2521005000174
AC208124
AC207331
AC207321
Front impact sensor
Front impact sensor
AC
Sensor internal circuit
Front impa ct sensor is in st alled out side o f the h ead-
lamp support p ane l in the en gine comp a r tmen t.
When th
e front imp a ct se nsor detect s an imp a ct dur
-
ing collision, the co nt a c t in the sensor turn s ON a nd
send
s out put signal to th e SRS-ECU. For d i agn osis,
the resist
an ce of the fro n t imp a ct sensor is con
-
nected in p a r a lle l with the cont act p o int.
SIDE IMPACT SENSOR
M25210060 0014 4
AC312729
AC207222
AC311719
Side impact
sensor
Side impact
sensor
Front door trim
AB
The side imp
a ct sensor is inst alled in the lower p a rt s
of th
e centre pillars an d cont ains a n an alog ue G-se n
-
sor.
The side imp a ct se nsor tran smit s cod ed acce le ration
dat
a to th e SRS-ECU. Base d on t he dat a, t he
SRS-ECU then d
e termines if th e side an d/or curt a i n
air
bags should be inflate d , a nd send s a n ignit i on sig
-
nal. The side imp a ct sen s or a l so diag nose s it s own
componen
t s , and send s a d i agno sis co de to t he
SRS-ECU if a p
r oble m occurs.

SYSTEM CONSTRUCTION
SUPPLEMENTAL RESTRAINT SYSTEM (SRS)52B-13
SEAT BELT WITH PRE-TENSIONER
M2521008000195
AC208129
AC207230AC207336ACPipe Gear
Ball Spool
Gas generator
The seatbelt incorpo
r ating the pre - tensioner auto-
matically winds the seatbelt upo n front imp a ct to
reduce forward shif
ting of th e p a ssenge r .
Upon front imp a ct the pre-ten s ion e r ig nites the g a s
generat
or and emit s gas with the SRS-ECU signal
whe
n t he front imp a ct sen s or , att a ched to the front of
the bo
dy , dete c t s a n imp a ct t hat excee d s t he per mis
-
sible limit. By this g a s p r essure, a ball moves in the
p
i p e and rot a tes the g ear . This gear rot a tion operat es
the spool
in the directio n of ret r acting the belt, and
the webbing is retra
c ted .
SRS-ECU
M25210070 0048 2
The SRS-ECU incorp orates an an alog ue G-sensor
and safing
G-sensor for fro n t a l collisions.
In frontal collision s , the dr iver's an d front p a ssenge r's
air ba
gs d eploy only when both t he ana logue and
safing G-sensors detect
simult a neously a co lli
-
sion -indu ced G of a le vel exceed ing the thresh old as
in the
case with the conve n tion al system.
The SRS-ECU is prov ide d with t he followin g cap a b i l-
ities:
•Backup p o wer su pply in case of po we r failure in
c
o lli si ons: Ba cku p ca p a cito r
•Boosting function in ca se of battery volt a ge drop :
DC-DC converter
•Self-diag nosis fu nction to a v oid syste m 's opera-
tion errors and imp r ove it s reliabilit y
CAUTION
Never disassemble the SRS-ECU.
DIAGNOSIS FUNCTION
The SRS-ECU has the following functions to make
system check using M.U.T.-III easy.
•Diagnosis code set
•Service data output

SYSTEM CONSTRUCTION
SUPPLEMENTAL RESTRAINT SYSTEM (SRS)52B-14
DIAGNOSIS CODE SET
The SRS-ECU diagnoses the following items and
stores a diagnosis code in the non-volatile memory
(EEPROM*1) when a problem is detected. There
-
fore, the memory is not deleted after a battery termi-
nal is disconnected. (The diagnosis code memory
can be deleted by the M.U.T.-III).
CODE NO.MAJOR CONTENTS OF DIAGNOSTICS
1AFront impact sensor LH systemShort circuit in the sensor
1BOpen circuit in the sensor
1CShort circuit in the power supply
1DShort circuit in the earth
2AFront impact sensor RH systemShort circuit in the sensor
2BOpen circuit in the sensor
2CShort circuit in the power supply
2DShort circuit in the earth
3A*3Curtain air bag squib (RH) short-circuited
3B*3Curtain air bag squib (RH) open-circuited
3CCurtain air bag squib (RH) activating circuit short-circuited
3DCurtain air bag squib (RH) activating circuit open-circuited
3ECurtain air bag squib (RH) drive circuit (power supply side) short-circuited
3FCurtain air bag squib (RH) drive circuit (earth side) short-circuited
4A*3Curtain air bag squib (LH) short-circuited
4B*3Curtain air bag squib (LH) open-circuited
4CCurtain air bag squib (LH) activating circuit short-circuited
4DCurtain air bag squib (LH) activating circuit open-circuited
4ECurtain air bag squib (LH) drive circuit (power supply side) short-circuited
4FCurtain air bag squib (LH) drive circuit (earth side) short-circuited
14Analog G-sensor malfunction
15Safing G-sensor short-circuited (for frontal collision)
16Safing G-sensor open-circuited (for frontal collision)
17Safing G-sensor malfunction (for side collision)
21*3Driver's air bag squib short-circuited
22*3Driver's air bag squib open-circuited
24*3Passenger's (front) air bag squib short-circuited
25*3Passenger's (front) air bag squib open-circuited
26*3Driver's pre-tensioner squib short-circuited
27*3Driver's pre-tensioner squib open-circuited
28*3Passenger's (front) pre-tensioner squib short-circuited
29*3Passenger's (front) pre-tensioner squib open-circuited
31SRS-ECU capacitor circuit voltage too high

SYSTEM CONSTRUCTION
SUPPLEMENTAL RESTRAINT SYSTEM (SRS)52B-15
32SRS-ECU capacitor circuit voltage too low
34*2SRS-ECU connector lock out of order
35Ignition of the air bag completed
39Simultaneous deployed
41*2Power supply voltage (IG1 (A) voltage) drops abnormally.
42*2Power supply voltage (IG1 (B) voltage) drops abnormally.
43*2SRS warning lamp circuit open-circuited
44*2SRS warning lamp circuit malfunction
45SRS-ECU non-volatile memory (EEPROM) and A/D converter system
51Driver's air bag squib activating circuit short-circuited
52Driver's air bag squib activating circuit open-circuited
54Passenger's (front) air bag squib activating circuit short-circuited
55Passenger's (front) air bag squib activating circuit open-circuited
56Driver’s seat belt pre-tensioner (squib ignition drive circuit) system detected short
57Driver’s seat belt pre-tensioner (squib ignition drive circuit) system detected open
58Passenger’s seat belt pre-tensioner (squib ignition drive circuit) system detected short
59Passenger’s seat belt pre-tensioner (squib ignition drive circuit) system detected open
61Driver's air bag squib drive circuit (power supply side) short-circuited
62Driver's air bag squib drive circuit (earth side) short-circuited
64Passenger's (front) air bag squib drive circuit (power supply side) short-circuited
65Passenger's (front) air bag squib drive circuit (earth side) short-circuited
66Driver's pre-tensioner squib (power supply side) short-circuited
67Driver's pre-tensioner squib (earth side) short-circuited
68Passenger's (front) pre-tensioner squib drive circuit (power supply side) short-circuited
69Passenger's (front) pre-tensioner squib drive circuit (earth side) short-circuited
71*3Side-airbag squib (RH) short-circuited
72*3Side-airbag squib (RH) open-circuited
73Side-airbag squib (RH) drive circuit shorted
74Side-airbag squib (RH) drive circuit open
75Side-airbag squib (RH) drive circuit (power supply side) shorted
76Side-airbag squib (RH) drive circuit (earth side) shorted
79Side impact sensor (LH) communication error
81*3Side-airbag squib (LH) shot-circuited
82*3Side-airbag squib (LH) open-circuited
83Side-airbag squib (LH) drive circuit shorted
84Side-airbag squib (LH) drive circuit open
85Side-airbag squib (LH) drive circuit (power supply side) shorted
86Side-airbag squib (LH) drive circuit (earth side) shorted
89Side impact sensor (RH) communication error
CODE NO. MAJOR CONTENTS OF DIAGNOSTICS

SYSTEM CONSTRUCTION
SUPPLEMENTAL RESTRAINT SYSTEM (SRS)52B-16
NOTE: .
•*1: Electrically Erasable Programmable ROM
•*2: This diagnosis code memory will be automatically cleared from the memory and the SRS warning
lamp will be switched off when the system returns to normal condition.
•*3: The diagnosis codes will remain in memory and the SRS warning lamp will be switched off if the sys-
tem returns to normal condition.
SERVICE DATA OUTPUT
When the SRS-ECU detects a problem, it stores a
diagnosis code and the duration that the problem has
lasted in the non-volatile memory. In addition, how
often a diagnosis code and duration are cleared by
the M.U.T.-III are stored in the non-volatile memory
as a reference for service work. This data can be
read by the M.U.T.-III.
No.Service Data ItemApplicability
92Number indicating how often the memory is clearedMaximum time to be stored: 250
times
93How long a problem has lasted (How long takes from the
occurrence of the problem until the first air bag squid Igniting
signal)Maximum time to be stored: 9999
minutes (approximately 7days)
94How long a problem has lasted (How long from the first air bag
squib igniting signal until now)
91*2Side impact sensor (LH) voltage error
92G-sensor of side impact sensor (LH) failure
93Side impact sensor (LH) communication impossible
94*2Side impact sensor (RH) voltage error
95G-sensor of side impact sensor (RH) failure
96Side impact sensor (RH) communication impossible
CODE NO. MAJOR CONTENTS OF DIAGNOSTICS

SYSTEM CONSTRUCTION
SUPPLEMENTAL RESTRAINT SYSTEM (SRS)52B-17
SRS AIR BAG SPECIAL CONNECTOR
M2521009000187
AC304767
SRS-ECUA
A
AAE
Clock spring Side-airbag module
(RH)
Seat belt with pre-tensioner
(front passenger's side)
Side-airbag module
(LH)
Seat belt with pre-tensioner
(driver's side) Passenger's (front)
air bag module
Driver's air bag module Curtain air bag module
(RH)
Curtain air bag module
(LH)
AA
T o en hance the system reliability , th e con nect o r
engage
ment che ck mechanism is u s ed. An d a con
-
nector lock switch is integ r ated in the SRS-ECU con-
nector , the a i r ba g mod u le conne ctors, the clo ck
spring co
nnector , the sea t belt pre-ten s io ner connec
-
tors (black connector "A" shown in the illustration
above).

SYSTEM CONSTRUCTION
SUPPLEMENTAL RESTRAINT SYSTEM (SRS)52B-18
SQUIB CIRCUIT CONNECTOR LOCK
SWITCH
AC300257
OFFON
OFF ON
Squib
SRS-ECU
A
A

ECU-side connectorB
B
AC
Section B - B
Section A - A
Connector connected
OFF
ON
OFF
ON
Squib
SRS-ECU
Connector disconnected
Terminal
(male)
Partition panelTerminal
(female) Short spring
Wiring harness-side connector
Terminal
(male)
Partition panel Terminal
(female)
Short spring Connector connected
Terminal
(male)
Partition panelTerminal
(female)
Short spring
Diagnosis spring
Diagnosis
spring
CAUTION
When the connector is disconnected, it is normal
for short-circuiting to occur between the connec
-
tor terminals.
•The diagnosis spring is assembled on the
SRS-ECU wiring harness-side connector. When
the ECU-side connector is connected to the
SRS-ECU wiring harness-side connector, the
diagnosis spring is disengaged from the terminal
to short the circuit between the ECU-side con
-
nector terminals. The connector engagement is
detected electrically by flowing the monitor cur
-
rent to this circuit.
•This mechanism automatically short-circuits the
power supply side terminal and earth side termi
-
nal of the air bag when the connector is discon-
nected. A short spring is incorporated in the
connector to short-circuit the power supply side
terminal and earth side terminal of the air bag (no
potential difference between the two terminals)
and prevent flow of current by static electricity to
the squib.