check engine MITSUBISHI MONTERO 1998 Service Manual

system.
3) Using scan tool, read Fuel Tank Differential Pressure
(FTDP) sensor (item 73). Using hand-held pressure/vacuum pump, apply\
0.42 psi. If scan tool reading reaches 0.42 psi, go to next step. If
reading does not reach 0.42 psi, go to step 8).
4) Disconnect EVAP canister purge hose. Connect Purge Flow
Indicator (MB995061) between EVAP canister and disconnected hose. Turn\
engine on and allow it to reach operating temperature. Turn all lights
and accessories off. Place transmission in Park or Neutral. Observe
purge flow indicator while increasing engine RPM several times. If
purge flow indicator reads less than 2.5 SCFH (20 cm(3)/sec), check
EVAP canister purge hose and EVAP canister port for clogging. If hose
and port are okay, check EVAP purge solenoid. See DTC P0443. If
solenoid is okay, replace EVAP canister. Go to step 20).
5) Using scan tool, read Engine Coolant Temperature (ECT)
sensor temperature (item 21). Compare scan tool reading with
temperature gauge reading. If readings are about the same, go to next
step. If readings are not about the same, go to DTC P0115 test.
6) Using a thermometer, check engine compartment ambient
temperature. Using scan tool, read Intake Air Temperature (IAT) sensor\
temperature (item 13). Compare IAT sensor and thermometer readings. If\
readings are not about the same, go to DTC P0110 test. If readings are
about the same, go to next step.
7) Using scan tool, read Power Steering Pressure (PSP) switc\
h
status (item 27). Switch status should read ON when steering wheel is
turned. If switch status is as specified, go to step 20). If switch
status is not as specified, go to DTC P0551 test.
8) Remove fuel cap. Install a fuel tank filler tube adapter
in place of fuel cap. Plug fuel filler tube adapter hose. Disconnect
and plug air filter-to-EVAP vent solenoid hose at air filter.
Disconnect intake manifold plenum-to-EVAP purge solenoid at intake
manifold plenum. Install a "T" fitting between vacuum hose and intake
manifold plenum. Connect hand-held pressure/vacuum pump to "T"
fitting. Go to next step.
CAUTION: DO NOT apply more than 0.57 psi in following step. Applying
more than specified psi can crack fuel tank.
NOTE: Ensure fuel tank is at least 1/4 full. The lower the fuel
level in fuel tank, the longer it takes to pressurize fuel
system.
9) Using scan tool, read Fuel Tank Differential Pressure
(FTDP) sensor (item 73). Using hand-held pressure/vacuum pump, apply\
0.42 psi. If scan tool reading reaches 0.42 psi, replace fuel cap. Go
to step 20). If reading does not reach 0.42 psi, go to next step.
10) Disconnect hand-held pressure/vacuum pump from "T"
fitting. Install an evaporative emission system tester in place of
vacuum held pump and apply 0.49 psi. Wait two minutes. If pressure
drops less than 0.20 psi, go to next step. If pressure drops 0.29 psi
or more, go to step 13).
11) Disconnect EVAP purge solenoid-to-EVAP canister hose at
EVAP canister. Connect hand-held pressure/vacuum pump to hose and
apply 0.9 psi. If pressure is not maintained, check EVAP purge
solenoid for leak. If EVAP purge solenoid is okay, replace hose. Go to
step 24). If pressure is maintained, go to next step.
12) Disconnect EVAP vent solenoid-to-EVAP canister hose at
EVAP canister. Connect hand-held pressure/vacuum pump to hose and
apply 0.9 psi. If pressure is not maintained, check EVAP vent solenoid
for leak. If EVAP vent solenoid is okay, replace hose. Go to step 20).
If pressure is maintained, replace EVAP canister. Go to step 24).
13) Ensure hoses are properly routed and connected. See M -

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.

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 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.

REFILLING
To prevent air from being trapped in engine block, engine
should be running when refilling cooling system. After system is full,
continue running engine until thermostat is open, then recheck fill
level. Do not overfill system.
TESTING
THERMOSTAT
1) Visually inspect thermostat for corrosion and proper
sealing of valve and seat. If okay, suspend thermostat and thermometer
in a 50/50 mixture of coolant and water. See Fig. 1. Do not allow
thermostat or thermometer to touch bottom of container. Heat water
until thermostat just begins to open.
2) Read temperature on thermometer. This is the initial
opening temperature and should be within specification. Continue
heating water until thermostat is fully open and note temperature.
This is the fully opened temperature. If either reading is not to
specification, replace thermostat.
Fig. 1: Testing Thermostat in Anti-Freeze/Water Solution
PRESSURE TESTING
A pressure tester is used to check both radiator cap and

ON-VEHICLE TESTING
GENERATOR TO BATTERY CONTINUITY TEST
NOTE: Check generator wiring harness connections and drive belt
tension and ensure battery is fully charged before
performing test.
1) Turn ignition off. Disconnect negative battery cable.
Remove output lead from generator terminal "B". See Fig. 1. Install a
100-amp or 130-amp ammeter in series with terminal "B" and
disconnected output lead. Install positive lead of ammeter to terminal
"B" and negative lead to disconnected output wire.
Fig. 1: Identifying Generator Terminals (Typical)
Courtesy of Mitsubishi Motor Sales of America
2) Install positive lead of digital voltmeter to terminal "B"
and negative lead to positive battery terminal. Install a tachometer
and reconnect negative battery cable.
3) Start and operate engine at 2500 RPM. Turn accessories on
and adjust engine speed until ammeter indicates slightly greater than
30 amps, and note voltmeter reading. If voltmeter indicates .3 volt or
less, system is okay.
4) If voltage is greater than .3 volt, check wiring between
generator terminal "B", fusible link and positive battery terminal. If
terminal is not sufficiently tight or if harness is discolored due to
overheating, repair as necessary and retest.

GENERATOR OUTPUT TEST
NOTE: A slightly discharged battery should be used, as a fully
charged battery may not allow full generator output.
1) Turn ignition off. Disconnect negative battery cable.
Disconnect generator output wire from terminal "B". Connect positive
lead of 100-amp ammeter to terminal "B" and negative lead to
disconnected output lead.
CAUTION: Tighten each connection securely, as heavy current flow will
exist. DO NOT use clips on ammeter. An inductive-type
ammeter is recommended.
2) Connect positive voltmeter lead (0-20 volts) to generator\
terminal "B" and negative lead to ground. Install a tachometer and
reconnect negative battery cable.
3) Ensure voltmeter indicates battery voltage. If voltage is
not present, check for open circuit in wire between generator terminal
"B" and positive battery terminal. Check grounds and fusible link.
4) Start engine and turn headlights on. Set headlights at
high beam and heater blower switch on HIGH. Increase engine speed to
2500 RPM and note generator output current on ammeter. Minimum output
should be within specification. See
GENERATOR MINIMUM OUTPUT SPECIFICATIONS table.
NOTE: Output voltage changes with electrical load and temperature.
Ensure proper electrical load is applied while checking
output. Nominal output may not be obtained if generator or
ambient temperature is excessive. Allow generator or
temperature to cool, and recheck output. Generator output is
stamped on metal plate attached to generator case.
5) If minimum output is not obtained and generator wiring is
okay, repair generator. Operate engine at idle speed after the test.
GENERATOR MINIMUM OUTPUT SPECIFICATIONS TABLE









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Application Amps
Diamante ............................................. 110
Eclipse
2.0L Non-Turbo ...................................... 90
2.0L Turbo .......................................... 75
2.4L ................................................ 90
Galant ................................................ 90
Mirage ................................................ 80
Montero .............................................. 100
Montero Sport
2.4L ................................................ 60
3.0L ................................................ 85
3000GT
DOHC ............................................... 110
SOHC ................................................ 90









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REGULATED VOLTAGE TEST
NOTE: Ensure battery is fully charged and proper drive belt
tension exists.
1) Turn ignition switch off. Disconnect negative battery
cable. Connect positive voltmeter lead to terminal "S" of generator.

See Fig. 1 . Connect negative voltmeter lead to ground.
2) Disconnect generator output wire from terminal "B".
Install a 100-amp ammeter in series with terminal "B" and disconnected
output lead. Connect positive lead of ammeter to terminal "B" and
negative lead to disconnected output wire. Install a tachometer, and
reconnect negative battery cable.
3) Turn ignition switch on and ensure voltmeter indicates
battery voltage. If voltage is not present, check for open in wire
between generator terminal "S" and positive battery terminal. Check
for blown fusible link.
4) Start engine. Ensure all lights and accessories are off.
Operate engine at 2500 RPM and read voltmeter when generator output
current drops to 10 amps or less. Voltage regulator is okay if voltage
output is within specification. See REGULATOR VOLTAGE SPECIFICATIONS
table.
REGULATOR VOLTAGE SPECIFICATIONS TABLE









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Ambient Temperature Voltage
-4
F (-20C) ................................... 14.2-15.4
68F (20C) .................................... 13.9-14.9
140F (60C) ................................... 13.4-14.6
176F (80C) ................................... 13.1-14.5








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GENERATOR RELAY TEST
NOTE: Information for all other models is not available from
manufacturer at time of publication.
Diamante & Mirage
Remove generator relay. On Diamante, relay is located in
relay box in engine compartment near battery. On Mirage, relay is
located in relay box in engine compartment between battery and strut
tower. On both models, connect positive lead of ohmmeter to relay
terminal No. 4. See WIRING DIAGRAMS. Connect negative lead of ohmmeter
to relay terminal No. 2. Continuity should be present. Switch ohmmeter
lead locations. Continuity should not be present. Replace generator
relay if continuity is not as specified.
BENCH TESTING
RECTIFIER ASSEMBLY
1) Using ohmmeter, check for continuity between diodes and
stator coil lead connection. See Fig. 2. Reverse leads. If continuity
is present in both directions, diode is shorted. Replace rectifier
assembly.
2) To check entire diode assembly, use an ohmmeter to check
for continuity between both ends of each diode. See Fig. 2. Switch
ohmmeter leads. Continuity should be present in one direction only. If
continuity is not as specified, diode is defective. Replace rectifier
assembly.