MITSUBISHI 3000GT 1991 Service Manual

SUPPLEMENTAL RESTRAINT SYSTEM (SRS) - Troubleshooting 52B-21
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FaultDiagnosis code nameNo.[Failure mode]Explanation
Service
41
IG VOLT LOW 1The multi-purpose fuse (No. 18) is blown or the wirefrom the fuse to the SDU is open-circuit or itsresistance value is increased.
It takes at least 5 seconds that the SDU detects
this fault.
Perform TEST 9
42
IG VOLT LOW 2The multi-purpose fuse (No. 11) is blown or the wirefrom the fuse to the SDU is open-circuit or itsresistance value is increased.
It takes at least 5 seconds that the SDU detects
this fault.
Perform TEST 10
SRS LMP TRBL 1
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The SRS warning light circuits are open or the wireWhen SRS warning lightOpen circuit orfrom the light to the SDU is grounded.does not extinguish:43ground shortIIt takes at least 5 seconds with the light OFF thatPerform TEST 11the SDU detects this fault.When SRS warning light
does not illuminate:
Perform TEST 12
SRS LMP TRBL 2The SRS warning light drive transistor (integrated
(1) Turn the ignition key
44SRS warning light
[I
in the SDU) is open-circuit.to the “LOCK” posi-
drive transistortion, disconnet the
is open-circuitnegative battery
cable and tape the
SRS DIAG. UNITThe EEP ROM or A/D converter (integrated in the SDU)terminal.is defective.(2) After waiting at
45least 30 seconds,
replace the SDU.
(Refer to P.52B-59.)
/NOTE -IMPORTANT
b(1) After repairing the SRS, reconnect the battery cable, erase the diagnosis code memory from theMulti-use Tester and check the SRS warning light operation to verify the system functions
properly. (Refer to TEST 1.)
(2) SDU
= SRS Diagnosis Unit
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52B-22 SUPPLEMENTAL RESTRAINT SYSTEM (SRS) - Troubleshooting
TEST 3NO COMMUNICATION BETWEEN MULTI-USE TESTER AND SDU
(SRS warning light does not extinguish)
COMBINATION METER(SRS WARNING LIGHT)
SRS DIPGNOSIS UNITSRS
diag(osis unit
View A13R0704To front impact sensor
(L.H.)
\To front impact sensor (R.H.)To
clock springI19FOllO
To body wiring harness (14-pin)
13R072113RO72:L
A double-lock mechanism is employed for the connec-
tor of the SRS diagnosis unit, so care must be taken notto damage it by using excessive force or by not
. .disconnecting it correctly.(4) Disconnect the red
IQpin connector from the SRS diagno- Q’sis unit while pressing down the lock of the connector.
(Refer to
P.52B-9.)
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(1) Turn the ignition key to the “LOCK” position, disconnect
the negative battery cable and tape the terminal.
Caution
Wait at least 30 seconds after disconnecting the battery
cable before doing any further work. The SRS system is
designed to retain enough voltage to deploy the air bagfor a short time even after the battery has been
disconnected, so serious injury may result from unin-
tended air bag deployment if work is done on the SRSsystem immediately after the battery cable is discon-
nected.(2) Remove the rear console assembly. (Refer to GROUP 52A
- Floor Console.)
(3) Use a screwdriver to push in the lock spring of the lock
lever of the SRS diagnosis unit to unlock the lock lever.
Caution
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lliSUPPLEMENTAL RESTRAINT SYSTEM (SRS)
- Troubleshootina 52B-23
L
MB991349SRS Check Harness
View ASRS Check Harness connector @
Diagnosis Fheck connector16R2166(5) Connect the now disconnected red harness-side SDU
connector
(l&pin) to the connector @ of the SRS Check
Harness.
(6) Check according to the flow chart below, using the
specified digital multi-meter.
III1 Body wiring harness dam-/1 Repair or replace the1Is there continuity between the No. 9terminal of SRS Check Harness connector@and the No. 8 terminal of the
diagnosis check connector (next to the
right side of the junction block)?
Diagnosis check connectorv
~ No
Is there continuity between the No. 13or No. 14 terminal of SRC Check
Harness connector @ and ground?
Yes
SDU is grounded.Repair or replace the body
+ wiring harness at the
location of the short cir-cuit.(Refer to P.52B-14.)NOTE
- IMPORTANT
(1) After repairing the SRS, reconnect the battery cable, erase the diagnosis code memory from theMulti-use Tester and check the SRS warning light operation to verify the system functions
properly. (Refer to TEST 1.)
(2) SDU
= SRS Diagnosis Unit
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52B-24 SUPPLEMENTAL RESTRAINT SYSTEM (SRS) - Troubleshooting
TEST 4NO COMMUNICATION BETWEEN MULTI-USE TESTER AND SDU
(SRS warning light does not illuminate)
IGNITION SWITCH(IG1)
J/.8(MULTI -PURPOSEFUSES)
SRS DIAGNOSIS UNIT
MULTI -3SETESTER1
KKRS-AX-RISE+R
View ASRS diagnbsis unit
To front impact sensor
(L.H.)
\To front impact sensor (R.H.)Toclock spring
I19FOllO
To body wiring harness (14-pin)
onnectornotch -UNLOCKED
;;bb;;,LOCKED zRok
(1) Turn the ignition key to the “LOCK” position, disconnect
the negative battery cable and tape the terminal.
Caution
Wait at least 30 seconds after disconnecting the battery
cable before doing any further work. The SRS system is
designed to retain enough voltage to deploy the air bagfor a short time even after the battery has been
disconnected, so serious injury may result from unin-
tended air bag deployment if work is done on the SRSsystem immediately after the battery cable is discon-
nected.(2) Remove the rear.console assembly. (Refer to GROUP 52A
- Floor Console.)
(3) Use a screwdriver to push in the lock spring of the lock
lever of the SRS diagnosis unit to unlock the lock lever.
Caution
A double-lock mechanism is employed for the connec-
tor of the SRS diagnosis unit, so care must be taken notto damage it by using excessive force or by not
disconnecting it correctly.
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i(4) Disconnect the red l4-pin connector from the SRS diagno- L/~
sis unit while pressing down the lock of the connector.
(Refer to
P.52B-9.)
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SUPPLEMENTAL RESTRAINT SYSTEM (SRS) - Troubleshooting 52B-25
r, NoIs there continuity between the No. 19‘1 ~~~~~i~k;~~~~.~~~-~4.~or No. 20 terminal of y:IsCheck ,-1 Ground circuit OpenIHarness connector @ and ground.
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MB991349SW Check Harness
View ASRSCheckHarness Connector
use No. 1116R2186
Fusk No. 18
Gxnd(5) Connect the now disconnected red harness-side SDU
connector
(14-pin) to the connector @ of the SRS Check
Harness.(6) Check according to the flow chart below using the digital
multi-meter.
Reconnect negative terminal of
battery, and turn the ignitionkey to the “ON” position.
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Does the voltage between the No. 11terminal (of SRS Check Harness connec-tor 0) and the No. 19 or 20 terminal
(ground) indicate system voltage?
Does the voltage between the No. 12
terminal (of SRS Check Harness connec-tor 0) and the No. 19 or 20 terminal
(ground) indicate system voltage?
Yes
p Malfunction of the SDU+ (1) Turn the ignition key
to the “LOCK” po-
sition, disconnect
the negative battery
cable and tape theterminal.
(2) After waiting at least
30 seconds, replace
the SDU. (Refer to
P.52B-59.)NOTE
- IMPORTkNT
cd
(1) After repairing the SRS, reconnect the battery cable, erase the diagnosis code memory from theMulti-use Tester and check the SRS warning light operation to verify the system functions
properly. (Refer to TEST 1.)
(2)
?Du =-SRS Diagnosis Unit
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52B-26 SUPPLEMENTAL RESTRAINT SYSTEM (SRS) - Troubleshooting
TEST 5REPAIR REQUIRED FOR "11. G-SENS. TRBL I”, “12. G-SENS. TRBL 2” or
“13. G-SENS. TRBL 3” FAULT
SRS DIAGNOSIS UN1
IMPACT S!NSOR~M&N"E DETECTION
FRONT IMPACTSENS0RtL.H.)FRONT IMPACTsEN80R(R. H. )--u-~,w-*
Front impact sensor resistance checkDigital multi-meter
r ~1iii”~“‘.,,,,/ ?\I. I,// q
NOTEIf combined front impact sensor and air bag module (squib) failure modes simultaneously occur in two places,
the preconditions for the respective detection circuits will go out of order. For this reason, both diagnosis
codes may not be stored but only one of them may be indicated.
Their relationships are shown in the following table.
Front impact sensors
Air bag module
(Squib)Short-circuitedOpen-circuitedShort-circuited
11 and/or 21
11 and/or 22One open-circuitedTwo open-circuited12 and/or 2113 and/or 21I12 and/or 2213 and/or 22
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The numbers in the boxes are diagnosis codes numbers. (Refer to P.52B-20.)
/SRS diagnosis unit
View A
13u070rTo frontimDact sensor
(L.H.)
ITo clock springI19FOllO
To body wiring harness (14-pin)
lQFO102
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SUPPLEMENTAL RESTRAINT SYSTEM (SRS) - Troubleshooting 529-27
MB991 349
SRS Check HarnessFront impact
sensor con-
nectar (R.H.)@ (blue)
View ASRS Check Harness connector @
Left
Right
16R2189
(I) Turn the ignition key to the “LOCK” position, disconnect
the negative battery cable and tape the terminal.
Caution
Wait at least 30 seconds after disconnecting the battery
cable before doing any further work. The SRS system is
designed to retain enough voltage to deploy the air bagfor a short time even after the battery has been
disconnected, so serious injury may result from unin-
tended air bag deployment if work is done on the SRSsystem immediately after the battery cable is discon-
nected.
(2) Remove the rear console assembly. (Refer to GROUP 52A-Floor Console.)
(3) Use a screwdriver to push in the lock spring of the lock
lever of the SRS diagnosis unit to unlock the lock lever.
Caution
A double-lock mechanism is employed for the connec-
tor of the SRS diagnosis unit, so care must be taken notto damage it by using excessive force or by not
disconnecting it correctly.(4) Disconnect each connector other than
14-pin connector
from the SRS diagnosis unit while pressing down the lock
of each connector. (Refer to
P.52B-9.)(5) Locate the blue and yellow connectors for the wiring
leading to the front impact sensors, which were connected
to the now-disconnected harness-side connector of the
SDU. Connect those blue and yellow connectors to
connector @ of the SRS Check Harness.
(6) Check according to the flow chart below, using the digital
multi-meter and Multi-use Tester.
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529-28 SUPPLEMENTAL RESTRAINT SYSTEM (SRS) - TroubleshootingI
I NoIs the resistance between the No. 3 Is the resistance between the No. 3terminal of SRS Check Harness connec- terminal of SRS Check Harness connec-
tor @ and the No. 4 terminal normal? tor @ and the No. 4 terminal normal?Standard value: 2,000 k 400Standard value: 2,000 k 400
Yes
the terminals of the leftfront impact sensor normal?(Refer to P.526-26.)Standard value:2,000 k 40R
Yes
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Front wiring harness is
grounded or open.
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?No -Is the resistance between the No. 5) Is the resistance between-Noterminal of SRS Check Harness connec-tor @ and the No. 6 terminal normal?the terminals of the right
Standard value: 2,000 2 4Oflfront impact sensor normal?(Refer to P.52B-26.)Standard value:Yes2,000 t 40R
Yes
Front wiring harness is
grounded or open.
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CONTINUED ON NEXT PAGENOTE
- IMPORTANT
(1) After repairing the SRS, reconnect the battery cable, erase the diagnosis code memory from thedMulti-use Tester and check the SRS warning light operation to verify the system functions
properly. (Refer to TEST 1.)
(2) SDU
= SRS Diagnosis Unit
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LSUPPLEMENTAL RESTRAINT SYSTEM (SRS)
- Troub!eshooting 529-29
/ CONTINUED FROM PREVIOUS PAGE/*
(1)Connect the red 2-pin connector @ of the SRS CheckHarness to the SDU in place of the now-disconnected clock spring-SDU connector.
NOTEA 3-ohm resistor that corresponds to the resistance
of the air bag module (squib) and the wiring resis-
tance is connected between the terminals of the
connector
@ of the SRS Check Harness.
(2)Reconnect blue.and yellow connectors, for the wiring
leading to the front impact sensors, to the SDU anddouble lock them. (Refer to
P.52B-9.)
NOTEIf double locking cannot be made, the connector isincorrectly or incompletely inserted; re-check to
insert the connector correctly and securely.
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CONTINUED ON NEXT PAGEIMB991 349
SRS Check Harness
SRS CheckHarness
\ ii%\19FOO93NOTE
- IMPORTANT
(I) After repairing the SRS, reconnect the battery cable, erase the diagnosis code memory from theMulti-use Tester and check the SRS warning light operation to verify the system functions
properly. (Refer to TEST 1.)
(2) SDU
= SRS Diagnosis Unit
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52B-30 SUPPLEMENTAL RESTRAINT SYSTEM (SRS) - Troubleshooting
1 CONTINUED FROM PREVIOUS PAGE-1
I/(I) Reconnect negative terminal of battery, and turn the.ignition key to the “ON” position.
(2) Using the Multi-use Tester, erase the diagnosis code_
memory. (Refer to TEST 1.)(3) Return the ignition key from the “ON” to the
“LOCK” position and then back to the “ON” position.
/
1 NoIs the SRS warning light operation
normal?) (1) Turn the ignition keyto the “LOCK” po-
Yessition, disconnect
the negative battery
cable and tape the
terminal.
(2) After waiting atleast 30 seconds,
replace the SDU.
(Refer to P.528-59.)
CautionWait at least 30 seconds after disconnecting the
battery cable before doing any further work. The
SRS system is designed to retain enough voltageto deploy the air bag for a short time even after
the battery has been disconnected, so serious
injury may result from unintended air bag deploy-ment if work is done on the SRS system im-
mediately after the battery cable is disconnected.(2) Use a screwdriver to push in the lock spring of the
lock lever of the SRS diagnosis unit to unlock the locklever.
CautionA double-lock mechanism is employed for the
connector of the SRS diagnosis unit, so care mustbe taken ‘not to damage it by using excessive
force or by not disconnecting it correctly.
(3)Disconnect the red 2-pin connector of the SRS Check
Harness from the SDU while pressing down the lockof the connector. (Refer to
P.52B-9.)
ICONTINUED ON NEXT PAGEI
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