2000 MITSUBISHI MONTERO Service Repair Manual

F
unctio ns S
C -E C U R
ece iv e s sig nals fr o m va rio us se nso rs , a nd tr a nsm it s an engin e outp utco ntr o ls ig nal
t o th e engin e-E C U or engin e-A /T -E C U,base d on th e in fo rm atio n. E
ngin e-E C U
< M /T , 4 M 4-A /T > T
ra nsm it s th e engin e in fo rm atio n (s u ch as APS sig nala nd engin e sp eed), w hic h is
r e quir e d fo r co ntr o lth e M it s u bis h iS C ,to th e SC -E C U. C
om pensa te fo r th e engin e outp ut acco rd in g to th e cu rre nt engin e co ndit io n on
r e quest fr o m th e SC -E C U. E
ngin e-A /T -E C U <6G 7-A /T > C
om pensa te fo r th e engin e outp ut acco rd in g to th e cu rre nt engin e co ndit io n on
r e quest fr o m th e SC -E C U. A
/T -E C U <4M 4-A /T > T
ra nsm it s th e tr a nsm is sio n in fo rm atio n (s u ch as sh if t posit io n), w hic h is re quir e d fo r
c o ntr o llin g th e M it s u bis h iS C ,to th e SC -E C U. A
BS-E C U T
ra nsm it s th e wheels p eed se nso r (F R )sig nalto th e SC -E C U. G
se nso r M
easu re s th e ve hic le la te ra lg ra vit y , and tr a nsm it th e in fo rm atio n to th e SC -E C U as
a vo lt a ge sig nal. V
ehic le sp eed se nso r T
ra nsm it s th e ve hic le sp eed (tr a nsm is sio n outp utg ear sp eed) sig nalto th e SC -E C U. S
C warn in g la m p I
llu m in ate s orfla sh es w hen th e SC -E C U tr a nsm it s a sig nalin dic a tin g th e syste m erro r. D
ia gnosis co nnecto r W
hen a dia gnosis co de is se t, th e MUT-II co m munic a te s wit h th e syste m via th is
c o nnecto r. S
ta ndard va lu e G
se nso r outp utvo lt a geV W
hen th e ve hic le is sta tio nary 2
.3 5 -2.6 5 W
hen an arro w on th e G se nso r la belis fa cin g dow n 3
.3 -3.7 N
o. N
am e A
pplic a tio n M
B991502 M
UT-II su b as-
s e m bly C
heckin g th e M IT S U BIS H IS C
( D ia gnosis dis p la y usin g th e M UT-II ) M
B991348 T
e st harn ess se t C
heckin g th e G se nso r

T
R O UBLE SH O OTIN G
S TA NDARD FLO W OF DIA G NO STIC TR O UBLE SH O OTIN G
R efe r to Basic Manual G RO UP 00 -How to Use Tro uble sh ootin g/In sp ectio n Serv ic e Poin ts .
S C WARNIN G LA M P IN SPEC TIO N
C heck th at th e SC warn in g la m p illu m in ate s as fo llo w s.
1 . When th e ig nit io n ke y is tu rn ed to “O N”, th e SC warn in g
l a m p will illu m in ate .
2 . When th e engin e is sta rte d, th e SC warn in g la m p will
b e sw it c h ed off .
3 . If th e illu m in atio n is oth er th an th e above , ch eck th e
d ia gnosis co des.
D IA G NO SIS FU NCTIO N
M ETH O D OF REA DIN G DIA G NO SIS CO DES
W HEN USIN G TH E MUT-
I I
C onnect th e MUT-
II t
o th e dia gnosis co nnecto r and ta ke a
r e adin g of th e dia gnosis co des.
C au tio n
T u rn th e ig nit io n sw it c h to “L O CK” (O FF) posit io n befo re
c o nnectin g or dis co nnectin g th e MUT-
I I .
W HEN USIN G TH E WARNIN G LA M P
1 . Use th e sp ecia l to ol to earth No.1 te rm in al (d ia gnosis
c o ntr o l te rm in al) of th e dia gnosis co nnecto r.
2 . Turn on th e ig nit io n sw it c h .
3 . Read out a dia gnosis co de by obse rv in g how th e warn in g
l a m p fla sh es.
( R efe r to Basic Manual GRO UP 00 -How to Use
T ro uble sh ootin g/In sp ectio n Serv ic e Poin ts .)
E R ASIN G DIA G NO SIS CO DES
C onnect th e MUT-
II t
o th e dia gnosis co nnecto r and era se
t h e dia gnosis co des.
C au tio n
T u rn th e ig nit io n sw it c h to “L O CK” (O FF) posit io n befo re
c o nnectin g or dis co nnectin g th e MUT-
I I .

MITSUBISHI SC-Troubleshooting13E-6
INSPECTION CHART FOR DIAGNOSIS CODES
Diagnosis
code No.Diagnosis itemSC warning lampReference page
27*1SC-ECU power supply system (abnormal voltage drop)Flashes13E-6
51*2Vehicle speed sensor wheel speed sensor system (output
signal abnormality)Flashes13E-7
52Vehicle speed sensor system (open circuit or short-circuit)Flashes13E-8
53*2Wheel speed sensor system (open circuit or short-circuit)Flashes13E-8
55*2G sensor systemFlashes13E-9
71Communication line between the engine-ECU or engine-
A/T-ECU and the systemFlashes13E-10
72Engine-ECU or Engine-A/T-ECU systemIlluminates13E-10
74*2Communication line between the A/T-ECU and the system
<4M4-A/T>Flashes13E-11
81*1The SC - ECU is controlling the system too longFlashes13E-11
NOTE
*1: Code No.27 and 81 are erased from the memory if the condition returns to normal.
*2: For code Nos.51, 53, 55 and 74, a diagnosis code will be set in ten seconds after a failure is detected.
INSPECTION PROCEDURE FOR DIAGNOSIS CODE
Code No. 27 SC-ECU power supply system (abnormal
voltage drop)Probable cause
This diagnosis code will be set if the SC-ECU power supply voltage drops below
a certain level.DMalfunction of battery
DMalfunction of harness or connector
DMalfunction of the SC-ECU
Caution
If the system voltage drops during inspection, this code will be output to indicate a current problem.
And correct problem diagnosis will not be possible. Before carrying out the following procedure,
check the battery and recharge it if necessary.


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MITSUBISHI SC-Troubleshooting MITSUBISHI SC-Troubleshooting13E-7
OK
NG
Repair
OK
Check the trouble symptoms.
NG
OKNG
Repair
OK
(1)NGCheck the following connectors:
B-25X, D-128, E-122,
E-121
NG
Check the harness wire between the engine control relay and
the SC-ECU, and repair if necessary. (2)NG
OK
Check the trouble symptoms.
NG
Replace
NG
Check the harness wire between the battery and the SC-ECU,
and repair if necessary.
Check the following connectors:
D-27, D-223 ,
D-31 , E-13, E-122, E-120
Measure at SC-ECU connectors E-120, E-121.
DDisconnect the connector and measure at the harness
side.
(1) Voltage between terminal 25 and body earth
(Ignition switch: ON)
OK:
System voltage
(2) Voltage between terminal 39 and body earth
OK:
System voltage
NG (1)NG
Check the harness wire between the SC-ECU and the body
earth, and repair if necessary.
Repair
NG
Replace the SC-ECU.
Check the trouble symptoms.
Check the following connectors:
E-120, E-122
NG
(2), (3)NG
Check the harness wire between the SC-ECU and the body
earth, and repair if necessary.
OK
NG
Repair
NGCheck the trouble symptoms.
Check the following connector:
E-121, E-122
OK
Check the trouble symptoms.
Measure at SC-ECU connector E-120, E-121.
DDisconnect the connector and measure at the harness
side.
(1) Continuity between 31 and body earth
OK:
Continuity
(2) Continuity between 13 and body earth
OK:
Continuity
(3) Continuity between 26 and body earth
OK:
Continuity
Check the trouble symptoms.
Check the fusible link No.2 and dedicated fuse No.7
Code No. 51 Vehicle speed sensor systemProbable cause
This diagnosis code will be set when the vehicle speed signal from the vehicle
speed sensor is not the same as that from the wheel speed sensor (FR).DMalfunction of vehicle speed sensor system
DMalfunction of wheel speed sensor system
DMalfunction of the SC-ECU
NG
Check the trouble symptoms.
Replace the SC-ECU.YES
NOCheck the vehicle speed sensor system (Refer to Basic
Manual GROUP 54A - Combination Meter).Does the speedometer operate normally?
YES
NOCheck the ABS system (Refer to Basic Manual GROUP 35B
- ABS).Does the ABS system operate normally?


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MITSUBISHI SC-Troubleshooting13E-8
Code No. 52 Vehicle speed sensor system (open circuit
or short-circuit)Probable cause
This diagnosis code will be set when the vehicle speed sensor does not send
vehicle speed signal to the SC-ECU.DMalfunction of vehicle speed sensor
DMalfunction of harness or connector
DMalfunction of the SC-ECU
NG
OK
Repair
NG
Check the trouble symptoms.
Replace the SC-ECUNG
OK
Repair YES
NOCheck the vehicle speed sensor system
(Refer to Basic Manual GROUP 54A - Combination Meter).
NG
Check the following connectors:
D-222, E-13, E-122, E-121
Does the speedometer operate normally?
Check the trouble symptoms.
Check the harness wire between J/B and SC-ECU.
Code No. 53 Wheel speed sensor system (open circuit
or short-circuit)Probable cause
This code is output when the open circuit or short-circuit detection carried out by
the ABS-ECU hardware circuit detects that there is an open circuit or
short-circuit in the (+) or ( - ) wire in one of the four wheel speed sensors and
signals are consequently not being input.DMalfunction of wheel speed sensor
DMalfunction of harness or connector
DMalfunction of the ABS-ECU
OK
NG
Check the trouble symptoms.
Replace the ABS-ECU
OK
NG
Check the harness wire between the SC-ECU and the
ABS-ECU
Check the trouble symptoms.
NG NG
YES
NOCheck the ABS system (Refer to Basic Manual GROUP 35B -
ABS.)
Check the following connectors:
E-106, E-122, E-120
Does the ABS system operate normally?
Measure at ABS-ECU connectors E-106.
DDisconnect the connector and measure at the harness
side.
DIgnition switch: ON
DVoltage between terminal 11 and body earth
OK:
4.8 - 5.2 V
RepairNG
OK
NG
Replace the SC-ECU
Check the trouble symptoms.RepairNG


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P
ro bab le cau se N
G N
G C
heck th e harn ess wir e , and re pair if nece ssa ry .
D B
etw een ig nit io n sw it c h and G se nso r O
K C
heck th e tr o uble sym pto m s. N
G
R ep air
O K (
1 )N G O
K R
epla ce th e G se nso r. N
G C
heck th e harn ess wir e , and re pair if nece ssa ry .
D B
etw een th e G se nso r and body earth O
K C
heck th e tr o uble sym pto m s. N
G
R ep air C
heck th e tr o uble sym pto m s.
Rep air C
heck th e harn ess wir e betw een th e G se nso r and SC -E C U
L
abel N
G O
K C
heck th e tr o uble sym pto m s.
w
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MITSUBISHI SC-Troubleshooting13E-10
Code No. 71 Communication line between the
engine-ECU or engine-A/T-ECU and the systemProbable cause
This diagnosis code will be set when an error takes place due to the open or
short circuit in the serial communication line between the SC-ECU and the
engine-ECU or engine-A/T-ECU, internal failure in the ECU or improper shield
line.DMalfunction of harness or connector
DMalfunction of engine-ECU or engine-A/T-ECU
DMalfunction of the SC-ECU
NG
NG
OK
Repair
NG
Check the trouble symptoms.
Replace the SC-ECUNG
OK
Repair
NGCheck the following connectors:
D-118 <6G7-M/T>, D-119
<6G7-A/T>, D - 112 <4M4>, E - 122, E-121
Check the trouble symptoms.
Check the harness wire between engine-ECU or
engine-A/T-ECU and SC-ECU.
Check the trouble symptoms.Replace the engine-ECU or engine-A/T-ECU
Code No. 72 Engine-ECU or Engine-A/T-ECU systemProbable cause
This diagnosis code will be set when the engine-ECU or engine-A/T-ECU detects
a system failure. On the GDI system <6G7> or diesel fuel system <4M4>, the
system failure is transmitted from the engine-ECU or engine-A/T-ECU via a
scenical communication line to the SC-ECU.DMalfunction of GDI system <6G7>
DMalfunction of diesel fuel system <4M4>
DCarry out the troubleshooting regarding the GDI system. <6G7>
(Refer to Basic Manual GROUP 13A - Troubleshooting.)
DCarry out the troubleshooting regarding the diesel fuel system. <4M4>
(Refer to Basic Manual GROUP 13C - Troubleshooting.)


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P
ro bab le cau se N
G N
G O
K C
heck th e tr o uble sym pto m s. R
epla ce th e SC -E C U N
G O
K C
heck th e tr o uble sym pto m s. C
heck th e harn ess wir e betw een A/T -E C U and SC -E C U. C
heck th e tr o uble sym pto m s. R
epla ce th e A/T -E C U
C ode No.81 The SC -E C U is co ntr o llin g th e syste m to o
l o ng P
ro bab le cau se O
K R
epla ce th e G se nso r. N
G
L abel L
abel
E -1 23
H arn ess -s id e
c o nnecto rw
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