1998 MITSUBISHI MONTERO Service Manual

specified VSS connector terminal. See
VSS VOLTAGE FEED CIRCUIT IDENTIFICATION table. If voltage is not 4.5-
4.9 volts, replace PCM. If voltage is as specified, condition required
to set DTC is not present at this time. Go to next step.
VSS VOLTAGE FEED CIRCUIT IDENTIFICATION TABLE









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Application Terminal No.
Montero ................................................ 1
3000GT ................................................. 3









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9) Test is complete. Intermittent problem may exist. Road
test vehicle (if necessary) and attempt to duplicate conditions that
caused original complaint. Recheck for DTCs. If no DTCs are displayed,
go to INTERMITTENT DTCS .
DTC P0505: IDLE CONTROL SYSTEM FAILURE
NOTE: For terminal identification, see TERMINAL IDENTIFICATION. For
circuit and wire color identification, see
L - WIRING DIAGRAMS article.
1) Procedures are provided by manufacturer for component
testing using an engine analyzer with oscilloscope capability. Refer
to manufacturer's operation manual for instructions in use of
oscilloscope. If using engine analyzer, go to step 3). If using scan
tool, go to next step.
2) Using scan tool, read Idle Air Control (IAC) position
sensor step (item 45). See IAC POSITION SENSOR STEP SPECIFICATIONS
table. If scan tool does not read as specified, replace IAC position
sensor. If readings are as specified, go to step 5).
IAC POSITION SENSOR STEP SPECIFICATIONS TABLE









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A/C Switch Position Standard Step Value
Off ................................................. 2-25
Off To On ............................ Increase From 10-70
( 1) ................................... Increase From 5-50
( 1) - Brakes applied. A/C Off on Montero. A/C On on 3000GT.
Move gear selector lever to Drive position.









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NOTE: Check wave pattern when idle speed increases when A/C is
turned on. Wave pattern display lasts less than one second.
3) Disconnect IAC motor connector. Install Test Harness
(MB998463) between IAC motor and connector. Using engine analyzer with\
oscilloscope capability, connect special patterns probe in sequence to
test harness terminals No. 1 (Red clip), 3 (Blue clip), 4 (Black cl\
ip)
and 6 (Yellow clip) or PCM terminals No. 4, 5, 17 and 18 respectively.\
Start engine and allow it to idle. Turn A/C on. Compare oscilloscope
wave pattern with known-good wave pattern. See Fig. 44. Turn engine
off. If wave pattern is not normal, go to next step. If wave pattern
is normal, fault is intermittent. See INTERMITTENT DTCS.

Fig. 44: Identifying Know-Good IAC Motor Wave Pattern
Courtesy of Mitsubishi Motor Sales of America
4) Disconnect IAC motor connector. Leave test harness
connected to IAC motor. Using DVOM, check resistance between test
harness terminals No. 2 (White clip) and either 1 (Red clip) or 3
(Blue clip), and between test harness terminals No. 5 (Green clip) a\
nd
either 4 (Black clip) or 6 (Yellow clip). Resistance should be 28-33\
ohms at 68
F (20C). If resistance is as specified, go to next step.
If resistance is not as specified, replace IAC motor. Go to step 10).
5) On 3000GT, go to step 7). On Montero, disconnect IAC motor\
connector and MFI relay connector. Check for continuity between IAC
motor connector terminal No. 2 and MFI relay connector terminal No. 1.
If continuity does not exist, repair wiring harness as necessary. If
continuity exists, go to next step.
6) Check for continuity between IAC motor connector terminal
No. 5 and MFI relay connector terminal No. 1. If continuity does not
exist, repair wiring harness as necessary. If continuity exists, go to
next step.
7) Disconnect IAC motor connector. Turn ignition switch to ON
position. Check voltage between chassis ground and IAC motor connector
terminals No. 2 and 5. If battery voltage does not exist on either
circuit, repair wiring harness as necessary. If battery voltage exists
on both circuits, go to next step.
8) Turn ignition switch to OFF position. Disconnect PCM
connector and IAC motor connector. Ground specified PCM connector
terminal and using DVOM, check continuity between chassis ground and
specified IAC motor connector terminal. See
PCM-TO-IAC MOTOR HARNESS CIRCUIT IDENTIFICATION table. If continuity
does not exist, repair wiring harness as necessary. If continuity
exists, go to next step.
PCM-TO-IAC MOTOR HARNESS CIRCUIT IDENTIFICATION TABLE









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PCM Terminal No. IAC Motor Terminal No.
14 ..................................................... 1
15 ..................................................... 4
28 ..................................................... 3
29 ..................................................... 6









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9) Test is complete. Intermittent problem may exist. Road
test vehicle (if necessary) and attempt to duplicate conditions that
caused original complaint. Recheck for DTCs. If no DTCs are displayed,
go to INTERMITTENT DTCS .
10) Road test vehicle and attempt to duplicate conditions
that caused original complaint. Recheck for DTCs. If no DTCs are
displayed, test is complete.
DTC P0510: CLOSED THROTTLE POSITION (TP) SWITCH FAILURE
NOTE: Closed TP switch is built into TP sensor. For DTC P0510
test purposes, TP sensor will be referred to as closed
TP switch. For terminal identification, see TP sensor under
TERMINAL IDENTIFICATION . For circuit and wire color
identification, see L - WIRING DIAGRAMS article.
1) If using scan tool, go to step 3). Disconnect closed TP
switch connector. Check for continuity between closed TP switch
connector terminals No. 1 and 2 on Montero or No. 3 and 4 on 3000GT.
Go to next step.
2) Depress accelerator pedal. Continuity should not exist.
Release accelerator pedal. Continuity should exist. If continuity is
not as specified, replace TP sensor. If continuity is as specified, go
to step 4).
3) Using scan tool, read closed TP switch state (item 26).
With accelerator pedal released, scan tool should read ON. With
accelerator pedal slightly depressed, scan tool should read OFF. If
closed TP switch does not test as specified, replace TP sensor. If
closed TP switch tests as specified, disconnect closed TP switch
connector and go to next step.
4) On 3000GT, go to next step. On Montero, turn ignition
switch to OFF position. Disconnect PCM connector. Ground PCM connector
terminal No. 79. Using DVOM, check continuity between chassis ground
and closed TP switch connector terminal No. 2. If continuity does not
exist, repair wiring harness as necessary. If continuity exists, go to
next step.
5) Check continuity between chassis ground and closed TP
switch connector terminal No. 1 on Montero or No. 4 on 3000GT. If
continuity does not exist, repair wiring harness as necessary. If
continuity exists, go to next step.
6) Turn ignition switch to ON position. Check voltage between
chassis ground and closed TP switch connector terminal No. 2 on
Montero or No. 3 on 3000GT. If voltage is less than 4 volts, replace
PCM. If voltage is more than 4 volts, condition required to set DTC is
not present at this time. Go to next step.
7) Test is complete. Intermittent problem may exist. Road
test vehicle (if necessary) and attempt to duplicate conditions that
caused original complaint. Recheck for DTCs. If no DTCs are displayed,
go to INTERMITTENT DTCS .
DTC P0551: POWER STEERING PRESSURE (PSP) SENSOR CIRCUIT
PERFORMANCE
NOTE: For terminal identification, see TERMINAL IDENTIFICATION. For
circuit and wire color identification, see
L - WIRING DIAGRAMS article.
1) Using scan tool, read Power Steering Pressure (PSP) statu\
s
(item 27). Switch status should read ON when steering wheel is turned.\
If switch status is as specified, fault is intermittent. See
INTERMITTENT DTCS . If switch status is not as specified, go to next
step.

2) Disconnect pressure hose from oil pump. See Fig. 45.
Install Adapter (MB990993) on oil pump. Install Adapter (MB990994) o\
n
disconnected hose. Connect Pressure Gauge (MB990662) and shutoff valve\
between adapters. Open shutoff valve. Bleed steering hydraulic system.
See HYDRAULIC SYSTEM BLEEDING in STEERING SYSTEM article.
Fig. 45: Testing PSP Sensor Circuit
Courtesy of Mitsubishi Motor Sales of America
3) Install a thermometer in fluid reservoir. Start engine and
allow it to idle. Turn steering wheel several times until fluid
temperature reaches 122-140
F (50-60C). Disconnect PSP switch
connector. Install a DVOM between ground and PSP switch terminal. See
Fig. 45 . Note continuity reading on DVOM. Go to next step.
4) With engine idling, gradually close shutoff valve to
increase power steering system pressure. Check pressure when PSP
switch is actuated by watching for a change in continuity. PSP switch

should be actuated when pressure is 218-290 psi. Gradually open
shutoff valve to decrease pressure. Check pressure when PSP switch is
de-actuated. PSP switch should de-actuate at 102-174 psi. Turn engine
off. If PSP operates as specified, go to next step. If PSP does not
operate as specified, replace PSP switch. Go to step 8).
5) Disconnect PSP switch connector. On 3000GT, go to next
step. On Montero, turn ignition off. Disconnect PCM connector. Ground
PCM connector terminal No. 54. Using DVOM, check continuity between
chassis ground and PSP switch connector terminal No. 1. If continuity
does not exist, repair wiring harness as necessary. If continuity
exists, go to next step.
6) Turn ignition on. Using DVOM, check voltage between ground
and PSP switch connector terminal No. 1. If battery voltage does not
exist, replace PCM. If battery voltage exists, go to next step.
7) Road test vehicle and attempt to duplicate conditions that
caused original complaint. Recheck for DTCs. If no DTCs are displayed,
test is complete.
DTC P0705: TRANSMISSION RANGE SENSOR CIRCUIT FAILURE
DTC P0705 is related to automatic transmission diagnostics.
For diagnostic procedure, see TRANSMISSION SERVICE & REPAIR article.
DTC P1103 & P1104: TURBOCHARGER WASTEGATE SOLENOID CIRCUIT
FAILURE
NOTE: This test applies to 3000GT with turbocharger only. For
terminal identification, see TERMINAL IDENTIFICATION. For
circuit and wire color identification, see
L - WIRING DIAGRAMS article.
1) If using scan tool, go to step 7). Remove vacuum hoses
from turbocharger wastegate solenoid. Disconnect solenoid harness
connector. Connect a vacuum pump to solenoid nipple "A". See Fig. 46.
Go to next step.
2) Using jumper wires, connect battery voltage and ground to
solenoid terminals. Ensure vacuum does not hold with nipple "B"
unplugged, and negative jumper wire connected. If solenoid does not
test as specified, replace solenoid. If solenoid tests as specified,
go to next step.
Fig. 46: Testing Turbocharger Wastegate Solenoid
Courtesy of Mitsubishi Motor Sales of America
3) Ensure solenoid holds vacuum with nipple "B" plugged, and
negative jumper wire connected. If solenoid does not test as

specified, replace solenoid. If solenoid tests as specified, go to
next step.
4) Ensure solenoid holds vacuum with nipple "B" unplugged,
and negative jumper wire disconnected. If solenoid does not test as
specified, replace solenoid. If solenoid tests as specified, go to
next step.
5) Check resistance between solenoid terminals. If resistance
is not 36-44 ohms at 68
F (20C), replace solenoid. If resistance is
as specified, go to next step.
6) Remove turbocharger by-pass valve. Connect vacuum pump to
by-pass valve nipple. Apply 16 in. Hg of vacuum. Ensure vacuum holds
and valve begins to open. If by-pass valve does not test as specified,
replace by-pass valve. If by-pass valve tests as specified, go to step
8).
7) Turn ignition switch to ON position. Using scan tool, turn
turbocharger wastegate solenoid on and off (item 12). Clicking sound
should be heard. If clicking sound is not heard, go to next step. If
clicking sound is heard, go to step 10).
8) Disconnect solenoid connector. Turn ignition switch to ON
position. Using DVOM, check for voltage between chassis ground and
solenoid connector terminal No. 1. If battery voltage does not exist,
repair wiring harness as necessary. If battery voltage exists, go to
next step.
9) Turn ignition switch to OFF position. Disconnect PCM
connector. Ground PCM connector terminal No. 41. Check continuity
between chassis ground and solenoid connector terminal No. 2. If
continuity does not exist, repair wiring harness as necessary. If
continuity exists, go to next step.
10) Test is complete. Intermittent problem may exist. Road
test vehicle (if necessary) and attempt to duplicate conditions that
caused original complaint. Recheck for DTCs. If no DTCs are displayed,
go to INTERMITTENT DTCS .
DTC P1105: FUEL PRESSURE SOLENOID FAILURE
NOTE: This test applies to 3000GT turbo only. For terminal
identification, see TERMINAL IDENTIFICATION. For circuit and
wire color identification, see L - WIRING DIAGRAMS article.
1) If using scan tool, go to step 6). Remove vacuum hoses
from fuel pressure solenoid. Disconnect solenoid harness connector.
Connect a vacuum pump to solenoid nipple "A". See Fig. 47. Apply
vacuum and go to next step.
2) Using jumper wires, connect battery voltage and ground to
solenoid terminals. Ensure solenoid does not hold vacuum with nipple
"B" unplugged, and negative jumper wire disconnected. If solenoid does
not test as specified, replace solenoid. If solenoid tests as
specified, go to next step.
Fig. 47: Testing Fuel Pressure Solenoid
Courtesy of Mitsubishi Motor Sales of America
3) Ensure solenoid holds vacuum with nipple "B" plugged, and
negative jumper wire disconnected. If solenoid does not test as

specified, replace solenoid. If solenoid tests as specified, go to
next step.
4) Ensure solenoid holds vacuum with nipple "B" unplugged,
and negative jumper wire connected. If solenoid does not test as
specified, replace solenoid. If solenoid tests as specified, go to
next step.
5) Check resistance between solenoid terminals. If resistance
is not 36-44 ohms at 68
F (20C), replace solenoid. If resistance is
as specified, go to step 7).
6) Turn ignition switch to ON position. Using scan tool, turn
fuel pressure solenoid on and off (item 09). Clicking sound should be
heard. If clicking sound is heard, go to step 9). If clicking sound is
not heard, go to next step.
7) Disconnect fuel pressure solenoid connector. Using DVOM,
check for voltage between chassis ground and fuel pressure solenoid
terminal No. 1. If battery voltage does not exist, repair wiring
harness as necessary. If battery voltage exists, go to next step.
8) Turn ignition switch to OFF position. Disconnect PCM
connector. Ground PCM connector terminal No. 48. Check continuity
between chassis ground and fuel pressure solenoid connector terminal
No. 2. If continuity does not exist, repair wiring harness as
necessary. If continuity exists, go to next step.
9) Test is complete. Intermittent problem may exist. Road
test vehicle (if necessary) and attempt to duplicate conditions that
caused original complaint. Recheck for DTCs. If no DTCs are displayed,
go to INTERMITTENT DTCS .
DTC P1400: MANIFOLD DIFFERENTIAL PRESSURE (MDP) SENSOR
CIRCUIT FAILURE
NOTE: For terminal identification, see TERMINAL IDENTIFICATION. For
circuit and wire color identification, see
L - WIRING DIAGRAMS article.
1) Component testing procedure without using scan tool not
available from manufacturer at time of publication. Warm vehicle to
normal operating temperature and allow engine to idle. Go to next
step.
2) Using scan tool, read intake manifold pressure (item 95).\
See INTAKE MANIFOLD PRESSURE SPECIFICATIONS table. If scan tool does
not read as specified, replace MDP sensor. If scan tool reads as
specified, go to next step.
INTAKE MANIFOLD PRESSURE SPECIFICATIONS TABLE









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Application psi (kPa)
Montero .............................. 3.0-4.9 (20.6-34.0)
3000GT
DOHC
Non-Turbo ........................ 3.7-5.7 (25.5-38.9)
Turbo ............................ 4.2-6.2 (29.0-42.4)
SOHC ............................... 3.9-5.8 (26.5-39.9)









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3) Disconnect MDP sensor connector. Using DVOM, check
continuity between chassis ground and MDP sensor connector terminal
No. 2. If continuity does not exist, repair wiring harness as
necessary. If continuity exists, go to next step.
4) Turn ignition switch to OFF position. With MDP sensor
connector disconnected, disconnect PCM connector. Ground PCM connector
terminal No. 92. Check continuity between chassis ground and MDP
sensor connector terminal No. 1. If continuity does not exist, repair

wiring harness as necessary. If continuity exists, go to next step.
5) Reconnect PCM connector. Turn ignition switch to ON
position. Check voltage between chassis ground and MDP sensor
connector terminal No. 3. If voltage is not 4.8-5.2 volts, replace
PCM. If voltage is as specified, condition required to set DTC is not
present at this time. Go to next step.
6) Test is complete. Intermittent problem may exist. Road
test vehicle (if necessary) and attempt to duplicate conditions that
caused original complaint. Recheck for DTCs. If no DTCs are displayed,
go to INTERMITTENT DTCS .
DTC P1600: SERIAL COMMUNICATION LINK MALFUNCTION
DTC P1600 is related to automatic transmission diagnostics.
For diagnostic procedure, see TRANSMISSION SERVICE & REPAIR article.
DTC P1715: PULSE GENERATOR FAILURE
DTC P1715 is related to automatic transmission diagnostics.
For diagnostic procedure, see TRANSMISSION SERVICE & REPAIR article.
DTC P1750: SOLENOID FAILURE
DTC P1750 is related to automatic transmission diagnostics.
For diagnostic procedure, see TRANSMISSION SERVICE & REPAIR article.
DTC P1791: ENGINE COOLANT TEMPERATURE LEVEL INPUT TO TCM
DTC P1791 is related to automatic transmission diagnostics.
For diagnostic procedure, see TRANSMISSION SERVICE & REPAIR article.
SUMMARY
If no hard DTCs (or only pass DTCs) are present, driveability\
symptoms exist, or intermittent DTCs exist, proceed to H - TESTS W/O
CODES article for diagnosis by symptom (i.e., ROUGH IDLE, NO START,
etc.) or intermittent diagnostic procedures.