1998 MITSUBISHI MONTERO check engine

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.

H - TESTS W/O CODES
1998 Mitsubishi Montero
1998 ENGINE PERFORMANCE
Mitsubishi - Trouble Shooting - No Codes
Diamante, Eclipse, Galant, Mirage, Montero, Montero Sport,
3000GT
INTRODUCTION
Before using this article to diagnose symptoms or
intermittent faults, perform testing in F - BASIC TESTING article and
G - TESTS W/CODES article. Use this article to diagnose driveability
problems existing when a hard Diagnostic Trouble Code (DTC) is not
present.
NOTE: Some driveability problems may have been corrected by
manufacturer with a revised Powertrain Control Module (PCM).
Check with manufacturer for latest PCM.
Symptom checks can direct technician to malfunctioning
component(s) for further diagnosis. A symptom should lead to a
specific component, system test or adjustment.
Use intermittent test procedures to locate driveability
problems that DO NOT occur when vehicle is being tested. These test
procedures should also be used if an intermittent DTC was present, but
no problem was found during self-diagnostic testing.
NOTE: For specific testing procedures, see G - TESTS W/CODES
article. For specifications, see D - ADJUSTMENTS or
C - SPECIFICATIONS article.
SYMPTOMS
SYMPTOM DIAGNOSIS
Symptom checks cannot be used unless problem occurs while
vehicle is being tested. Before using this article to diagnose any
symptom, perform basic diagnostic procedures in F - BASIC TESTING
article and self-diagnostics in G - TESTS W/CODES article in order to
reduce diagnostic time. The following symptoms are available for
diagnosis:
* Difficult To Start/No Start (Cranks Okay)
* Rough Or Unstable Idle
* Engine Hesitates Or Poor Acceleration
* Engine Surges
* Detonation Or Knocking
* Poor Fuel Mileage
DIFFICULT TO START/NO START (CRANKS OKAY)
* Check idle air control (DC) motor (if applicable).
* Check idle air control (stepper) motor (if applicable).
* Check ignition switch.
* Check camshaft position sensor.
* Check crankshaft position sensor.
* Check park/neutral position switch (A/T).
* Check volume airflow sensor.
* Check engine coolant temperature sensor.

* Check power supply to PCM.
* Check fuel pressure.
* Check ignition timing.
* Check for disconnected or damaged vacuum hoses.
* Check for control relay malfunction.
* Check for SFI system malfunction.
* Check for fuel pump drive control system malfunction.
* Check for ignition coil malfunction.
* Check for power transistor malfunction (if applicable).
* Check for fuel injector malfunction.
* Check for PCM malfunction.
* Ensure electrical harness, connectors and wires are not
broken, bent or loose.
ROUGH OR UNSTABLE IDLE
* Check intake air temperature sensor.
* Check EVAP purge control solenoid valve (if applicable).
* Check vehicle speed sensor.
* Check engine coolant temperature sensor.
* Check barometric pressure sensor (if applicable).
* Check manifold absolute pressure sensor (if applicable).
* Check ignition switch.
* Check throttle position sensor.
* Check camshaft position sensor.
* Check crankshaft position sensor.
* Check power steering oil pressure switch (if applicable).
* Check A/C switch and power relay (if applicable).
* Check park/neutral position switch (A/T).
* Check heated oxygen sensor.
* Check volume airflow sensor.
* Check fuel pressure.
* Check for disconnected or damaged vacuum hoses.
* Check for SFI system malfunction.
* Check idle air control (DC) motor (if applicable).
* Check idle air control (stepper) motor (if applicable).
* Check for fuel injector malfunction.
* Check for power transistor malfunction (if applicable).
* Check for vehicle speed sensor malfunction.
* Check for PCM malfunction.
* Ensure electrical harness, connectors and wires are not
broken, bent or loose.
ENGINE HESITATES OR POOR ACCELERATION
* Check intake air temperature sensor.
* Check engine coolant temperature sensor.
* Check barometric pressure sensor (if applicable).
* Check manifold absolute pressure sensor (if applicable).
* Check ignition switch.
* Check ignition coil.
* Check EGR control solenoid valve (if applicable).
* Check throttle position sensor.
* Check camshaft position sensor.
* Check crankshaft position sensor.
* Check power steering oil pressure switch (if applicable).
* Check A/C switch and power relay (if applicable).
* Check park/neutral position switch (A/T).
* Check heated oxygen sensor.
* Check volume airflow sensor.
* Check fuel pressure.
* Check for disconnected or damaged vacuum hoses.
* Check for SFI system malfunction.

* Check idle air control (DC) motor (if applicable).
* Check idle air control (stepper) motor (if applicable).
* Check for fuel injector malfunction.
* Check for power transistor malfunction (if applicable).
* Check A/C switch and power relay (if applicable).
* Check for PCM malfunction.
* Ensure electrical harness, connectors and wires are not
broken, bent or loose.
ENGINE SURGES
* Check engine coolant temperature sensor.
* Check EGR control solenoid valve (if applicable).
* Check fuel pressure.
* Check for fuel injector malfunction.
DETONATION OR KNOCKING
* Check for knock sensor malfunction (if applicable).
* Check volume airflow sensor.
* Check for engine cooling system problems.
* Check fuel quality.
* Check intake air temperature sensor.
* Check barometric pressure sensor (if applicable).
* Check manifold absolute pressure sensor (if applicable).
* Check ignition coil.
* Check power transistor (if applicable).
* Check for EGR system malfunction.
POOR FUEL MILEAGE
* Check intake air temperature sensor.
* Check engine coolant temperature sensor.
* Check barometric pressure sensor (if applicable).
* Check manifold absolute pressure sensor (if applicable).
* Check ignition switch.
* Check throttle position sensor.
* Check camshaft position sensor.
* Check crankshaft position sensor.
* Check power steering oil pressure switch (if applicable).
* Check A/C switch and power relay (if applicable).
* Check park/neutral position switch (A/T).
* Check heated oxygen sensor.
* Check volume airflow sensor.
* Check fuel pressure.
* Check for SFI system malfunction.
* Check idle air control (DC) motor (if applicable).
* Check idle air control (stepper) motor (if applicable).
* Check for fuel injector malfunction.
* Check for power transistor malfunction (if applicable).
INTERMITTENTS
INTERMITTENT PROBLEM DIAGNOSIS
Intermittent fault testing requires duplicating circuit or
component failure to identify problem. These procedures may lead to
computer setting a Diagnostic Trouble Code (DTC) which may help in
diagnosis.
If problem vehicle does not produce DTCs, monitor voltage or
resistance values using a DVOM while attempting to reproduce
conditions causing intermittent fault. A status change on DVOM

I - SYSTEM/COMPONENT TESTS
1998 Mitsubishi Montero
1998 ENGINE PERFORMANCE
Mitsubishi - System & Component Testing
Diamante, Eclipse, Galant, Mirage, Montero, Montero Sport,
3000GT
INTRODUCTION
NOTE: Testing individual components does not isolate shorts or
opens. Perform all voltage tests using a Digital
Volt-Ohmmeter (DVOM) with minimum 10-megohm input impedance,
unless stated otherwise in test procedure. Use ohmmeter to
isolate wiring harness shorts or opens. Testing procedures
not covered in this article require a scan tool. See
G - TESTS W/CODES article.
Before testing separate components or systems, perform basic
diagnostic procedures in F - BASIC TESTING article. Since many
computer-controlled and monitored components set a diagnostic trouble
code if they malfunction, also perform self-diagnostics in G - TESTS
W/CODES article.
AIR INDUCTION SYSTEMS
TURBOCHARGER
Turbocharger Pressure Check
1) Disconnect Black turbocharger pressure control hose at
wastegate solenoid valve, and plug valve nipple. Attach pressure gauge
to hose. Drive vehicle and accelerate engine, in 2nd gear, to 3500 RPM
or more. Check turbocharger pressure when pressure gauge stabilizes.
See TURBOCHARGER PRESSURE SPECIFICATIONS table.
2) If pressure gauge reading is more than specified, check
wastegate actuator. See DTCs P1103 and P1104 in G - TESTS W/CODES
article. Replace wastegate actuator as required. If pressure gauge
reading is less than specified, check for malfunctioning wastegate
valve, turbocharger pressure leaks and faulty turbocharger.
TURBOCHARGER PRESSURE SPECIFICATIONS TABLE









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Application Pressure psi (kg/cm)
Eclipse ................................ 6.4-14.7 (.4-1.0)
3000GT ................................... 2.9-8.7 (.2-.6)









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Air By-Pass Valve
Remove air by-pass valve. Valve is mounted to intake air duct
between air-to-air intercooler and intake plenum. Apply vacuum to
diaphragm of vacuum valve. Valve should begin opening at approximately
16 in. Hg. Observe operation of valve through by-pass opening.
Wastegate Actuator Test
Actuator is mounted on turbocharger. For testing procedures,
see DTCs P1103 and P1104 in G - TESTS W/CODES article.
Wastegate Control Solenoid Valve Test
On Eclipse, valve is mounted to top back section of air
cleaner. On 3000GT, valve is mounted to firewall, beside EGR solenoid.