1997 MITSUBISHI TRITON Workshop Manual

SRS ± Troubleshooting52B-8
Code No. 21 or 22 Air bag module (squib) systemProbable cause
(1) These diagnosis codes are output if there is abnormal resistance between the
input terminals of the air bag module (squib).
The trouble causes for each code No. are as follows. (Refer to chart 1.)
(2) Diagnosis codes 21 and 22 are sometimes generated in combination with
malfunction codes relating to the front impact sensor (code Nos. 11, 12 and 13),
but sometimes only one may be output instead of both being memorized. Because
of this, the front impact sensor should also be inspected at the same time. The
relationships between the codes are as follows. (Refer to chart 2.)
Malfunction of clock spring

Malfunction of wiring harnesses or connectors

Malfunction of air bag module (squib)

Malfunction of SDU
Chart 1
Code No.Trouble Symptom
21
Short in air bag module (squib) or harness short

Short in clock spring

Short in air bag module (squib) or front impact sensor harnesses leading to the power supply
22
Open circuit in air bag module (squib) or open harness

Open circuit in clock spring

Malfunction of connector contact

Short in air bag module (squib) or front impact sensor harnesses leading to the power supply
Chart 2
ItemFront impact sensor
ShortOpen circuit
(1 sensor)Open circuit
(2 sensors)
Air bag module (squib)Short11 or 2112 or 2113 or 21
Open circuit11 or 2212 or 2213 or 22
Caution
Do not attempt to measure the air bag module (squib) circuit resistance. Use of a tester in measuring
the circuit resistance will supply current to the squib, or erroneous deployment due to static electricity
could cause serious injury.

M
UT-II D IA G NO SIS C O DE

Dis co nnect c lo ck s p rin g c o nnec-
t o r C -7 5.

Connect S R S c h eck h arn ess
c o nnecto r ( 1 )

Era se d ia gnosis c o de m em ory
A re c o de N os. 2 1 a nd 2 2 o utp ut? N
o C
lo ck s p rin g c h eck. ( R e-
f e r to P .5 2B -3 2.) N
G
Rep la ce C
heck tr o uble s ym pto m . N
G R
epla ce th e a ir b ag m od-
u le ( s q uib ). S
R S c h eck h arn ess
c o nnecto r
SD U
R esis ta nce
( 3 W )
M B991349 N
o C
heck th e h arn ess w ir e
b etw een th e S D U a nd
c lo ck s p rin g, a nd r e pair
i f n ece ssa ry . Y
es Y
es C
heck th e fr o nt im pact
s e nso r s yste m ( R efe r to
P .5 2B -2 5.) O
K R
epla ce th e S D U.
C ode N o. 3 1 o r 3 2 S D U c ap acit o r s yste m P
ro bab le c au se T
he c a pacit o r in sid e th e S D U is p ro bably d efe ctiv e , s o r e pla ce th e S D U. H ow eve r,
c o de N o. 3 2 c o uld a ls o b e a r e su lt o f a s h ort in th e fr o nt im pact s e nso r, s o in sp ectio n
o f th e fr o nt im pact s e nso r s yste m s h ould a ls o b e c a rrie d o ut. ( R efe r to P . 5 2B -2 5.)

P
ro bab le c au se N
G
1 N
G C
heck tr o uble s ym pto m s. O
K C
heck tr o uble s ym pto m s. O
K M
easu re a t S R S c h eck h arn ess c o nnecto r ( 5 ).

Dis co nnect S D U c o nnecto r

Connect S R S c h eck h arn ess c o nnecto r ( 3 )

Ig nit io n s w it c h O N

Volt a ge b etw een te rm in al ( 1 0) a nd b ody e arth
O K: 0 V O
K R
epla ce th e S D U. N
G C
heck th e h arn ess b etw een th e S D U a nd ig nit io n s w it c h ( S T) < P et-
r o l- p ow ere d v e hic le s> o r S D U a nd s ta rte r r e la y < D ie se l- p ow ere d
v e hic le s> , a nd r e pair if n ece ssa ry . N
G C
heck th e h arn ess w ir e b etw een e ach , S D U a nd e arth ,
a nd r e pair if n ece ssa ry .

P
ro bab le c au se I
s th e S D U e ngagem ent d ete ctio n m ech anis m o pera tin g c o rre ctly ? N
o I
n se rt th e c o nnecto r s e -
c u re ly a nd lo w er th e lo ck
l e ve r to lo ck th e c o nnec-
t o r. Y
es R
epla ce th e S D U.
C ode N o. 4 1 IG
1
( A ) p ow er c ir c u it s yste m P
ro bab le c au se M
easu re a t S R S c h eck h arn ess c o n-
n ecto rs ( 5 ).

Dis co nnect S D U c o nnecto r
C -2 7.

Connect S R S c h eck h arn ess
c o nnecto r ( 3 ).

Contin uit y b etw een te rm in als
( 1 9) ± ( 2 0)
O K: C ontin uit y N
G C
heck tr o uble s ym pto m . N
G C
heck th e h arn ess w ir e b etw een th e S D U a nd e arth ,
a nd r e pair if n ece ssa ry . O
K M
easu re a t S R S c h eck h arn ess c o nnecto r ( 5 ).

Ig nit io n s w it c h O N

Volt a ge b etw een te rm in al ( 1 2) a nd b ody e arth
O K: 9 V o r m ore N
G R
epla ce th e S D U. O
K C
heck tr o uble s ym pto m s. N
G C
heck th e h arn ess b etw een th e S D U a nd ig nit io n s w it c h IG
1
( A ),
a nd r e pair if n ece ssa ry .

P
ro bab le c au se M
easu re a t S R S c h eck h arn ess c o n-
n ecto r ( 5 ).

Dis co nnect S D U c o nnecto r
C -2 7.

Connect S R S c h eck h arn ess
c o nnecto r ( 3 ).

Contin uit y b etw een te rm in als
( 1 9) ± ( 2 0)
O K: C ontin uit y N
G C
heck tr o uble s ym pto m . N
G C
heck th e h arn ess b etw een th e S D U a nd e arth , a nd
r e pair if n ece ssa ry . O
K M
easu re a t S R S c h eck h arn ess c o nnecto r ( 5 ).

Ig nit io n s w it c h : O N

Volt a ge b etw een th e te rm in al ( 1 1 ) a nd b ody e arth .
O K: 9 V o r m ore N
G R
epla ce th e S D U. O
K C
heck tr o uble s ym pto m . N
G C
heck th e h arn ess w ir e b etw een th e S D U a nd ig nit io n s w it c h IG
1
( B ), a nd r e pair if n ece ssa ry .

P
ro bab le c au se M
easu re a t S R S c h eck h arn ess c o n-
n ecto rs ( 5 ).

Dis co nnect S D U c o nnecto r
C -2 7.

Connect S R S c h eck h arn ess
c o nnecto r ( 3 ).

Contin uit y b etw een te rm in als
( 1 9) ± ( 2 0)
O K: C ontin uit y N
G C
heck tr o uble s ym pto m . N
G C
heck th e h arn ess w ir e b etw een th e S D U a nd e arth ,
a nd r e pair if n ece ssa ry . O
K M
easu re a t S R S c h eck h arn ess c o nnecto r ( 5 ).

Ig nit io n s w it c h O N

Connect te rm in al ( 1 3) to b ody e arth .
O K: L am p illu m in ate s. N
G B
lo w n S R S w arn in g la m p
b ulb c h eck. N
G
Rep air C
heck t h e f o llo w in g
c o nnecto rs :
C -2 7, C -8 6, C -8 7, C -8 8 N
G
Rep air O
K R
epla ce th e S D U. O
K C
heck tr o uble s ym pto m . C
heck th e h arn ess w ir e
b etw een th e S D U a nd
i g nit io n s w it c h ( IG
1)
, a nd
r e pair if n ece ssa ry . N
G
Rep air O
K R
epla ce th e c o m bin atio n
m ete r.

SRS ± Troubleshooting52B-14
Code No.43 SRS warning lamp drive circuit system
(Lamp does not switch off.)Probable cause
This diagnosis code is output when a short to earth occurs in the harness between
the lamp and the SDU while SDU is monitoring the SRS warning lamp and the lamp
is ON.
Malfunction of wiring harnesses or connectors

Malfunction of SDU

Malfunction of combination meter
SRS warning lamp inspection

Ignition switch: ON

Does lamp switch off when SDU connector C-27 is
disconnected?NoCheck the following
connectos:
C-06, C-27NG
Repair
Ye s
Replace the SDU.
OK
Check trouble symptoms.
NG
Check the harness wire
between the SDU and
combination meter, and
repair if necessary.
Code No.44 SRS warning lamp drive circuit systemProbable cause
This diagnosis code is output when a short occurs in the lamp drive circuit or a
malfunction of the output transistor inside the SDU is detected while the SDU is
monitoring the SRS warning lamp drive circuit.
Malfunction of wiring harnesses or connectors

Malfunction of SDU
Check the SRS warning lamp drive circuit system.
(Refer to P.52B-13.)OKReplace the SDU.
Code No.45 SDU non-volatile memory (EEPROM) and A/D
converter systemProbable cause
This diagnosis code is output if there is a malfunction in the SDU non-volatile memory
(EEPROM) and A/D converter.
Malfunction of SDU
Replace the SDU.
INSPECTION CHART FOR TROUBLE SYMPTOMS52400340126
Get an understanding of the trouble symptoms and check according to the inspection procedure chart.
Trouble symptomInspection procedure No.Reference page
Communication with
MUT-II is not possible.Communication with all systems is not
possible.152B-15
Communication is not possible with
SRS only.252B-15
When the ignition key is turned to ªONº (engine stopped), the
SRS warning lamp does not illuminate.Refer to diagnosis code No.43.52B-13
After the ignition switch is turned to ON, the SRS warning lamp
is still on after approximately 7 seconds have passed.Refer to diagnosis code No.43.52B-14

P
ro bab le c au se R
efe r to G RO UP 1 3A ± T ro uble sh ootin g.
I n sp ectio n P ro ced ure 2
C om munic atio n w it h M UT-II is n ot p ossib le .
( C om munic atio n is n ot p ossib le w it h S R S o nly .) P
ro bab le c au se M
easu re a t S R S c h eck h arn ess
c o nnecto r ( 5 ).

Dis co nnect S D U c o nnecto r
C -2 7.

Connect S R S c h eck h ar-
n ess c o nnecto r ( 3 ).

Contin uit y b etw een te rm i-
n als ( 1 9) ± ( 2 0)
O K: Contin uit y N
G O
K C
heck tr o uble s ym pto m s. N
G C
heck th e h arn ess w ir e b etw een th e S D U a nd e arth , a nd r e pair
i f n ece ssa ry . O
K C
heck tr o uble s ym pto m s. N
G C
heck th e h arn ess w ir e b etw een th e S D U a nd ig nit io n s w it c h IG
1,
a nd r e pair if n ece ssa ry . O
K C
heck th e h arn ess w ir e b etw een th e S D U a nd d ia gnosis c o nnecto r. N
G
Rep air R
epla ce th e S D U. 3
5 M
easu re a t S R S c h eck h arn ess c o nnecto r ( 5 ).

Ig nit io n s w it c h : O N

Volt a ge b etw een te rm in al ( 1 1 ) a nd b ody e arth
O K: 9 V o r m ore

Volt a ge b etw een te rm in al ( 1 2) a nd b ody e arth
O K: 9 V o r m ore N
G