
Heated Oxygen Sensor (Front)
(Federal) Underside of vehicle, forward
of catalytic converter.
Heated Oxygen Sensor (Front)
(Left Bank) (Calif.) In left exhaust manifold.
Heated Oxygen Sensor (Front)
(Right Bank) (Calif.) In right exhaust manifold.
Heated Oxygen Sensor (Rear)
(Federal) Underside of vehicle, behind
catalytic converter.
Heated Oxygen Sensor (Rear) (Left Bank)
(Calif.) In left exhaust pipe, below
engine.
Heated Oxygen Sensor (Rear) (Right Bank)
(Calif.) In right exhaust pipe, below
engine.
Input Shaft Speed Sensor On side of transmission.
Intake Air Temperature Sensor Mounted on outside of
evaporator case.
Manifold Differential Pressure Sensor On top left rear of engine.
Output Shaft Speed Sensor On rear of transmission.

TROUBLE CODE DEFINITION
When DTC is obtained, refer to appropriate DTC test
procedure.
DIAGNOSTIC TROUBLE CODES (DTCS)
NOTE: DTCs can only be retrieved by using a scan tool. Listed DTCs
are retrieved using a generic scan tool. MUT II scan tool
can be used, but it may not read all DTCs. DTCS listed are
not used on all vehicles.
DTC P0100
Volume Airflow (VAF) circuit failure. Possible causes are:
connector or harness, or faulty VAF sensor.
DTC P0105
Barometric (BARO) pressure circuit failure. Possible causes
are: connector or harness, or faulty BARO pressure sensor.
DTC P0105
Manifold Absolute Pressure (MAP) circuit failure. Possible
causes are: connector or harness, or faulty MAP sensor.
DTC P0110
Intake Air Temperature (IAT) circuit failure. Possible causes\
are: connector or harness, or faulty VAF sensor.
DTC P0115
Engine Coolant Temperature (ECT) circuit failure. Possible
causes are: connector or harness, or faulty ECT sensor.
DTC P0120
Throttle Position (TP) circuit failure. Possible causes are:
connector or harness, or faulty TP sensor.
DTC P0125
Excessive time to enter closed loop fuel control. Possible
causes are: faulty front HO2S, HO2S connector or harness, or faulty
fuel injector.
DTC P0130
Front Heated Oxygen Sensor (HO2S) circuit failure. Possible
causes are: connector or harness, or faulty HO2S.
DTC P0135
Front Heated Oxygen Sensor (HO2S) heater circuit failure.
Possible causes are: connector or harness, or faulty HO2S.
DTC P0136
Rear Heated Oxygen Sensor (HO2S) circuit failure. Possible
causes are: connector or harness, or faulty HO2S.
DTC P0141
Rear Heated Oxygen Sensor (HO2S) heater circuit failure.
Possible causes are: connector or harness, or faulty HO2S.
DTC P0150
Heated Oxygen Sensor (HO2S) circuit failure (bank 2, sensor
1). Possible causes are: connector or harness, or HO2S.

DTC P0155
Heated Oxygen Sensor (HO2S) heater circuit failure (bank 2,
sensor 1). Possible causes are: connector or harness, or HO2S.
DTC P0156
Heated Oxygen Sensor (HO2S) circuit failure (bank 2, sensor
2). Possible causes are: connector or harness, or HO2S.
DTC P0161
Heated Oxygen Sensor (HO2S) heater circuit failure (bank 2,
sensor 2). Possible causes are: connector or harness, or HO2S.
DTC P0170
Fuel trim failure (bank 1). Possible causes are: intake air
leaks, cracked exhaust manifold, faulty VAF sensor frequency, HO2S,
injector, fuel pressure, ECT, IAT or BARO pressure sensor.
DTC P0173
Fuel trim failure (bank 2). Possible causes are: intake air
leaks, cracked exhaust manifold, faulty VAF sensor frequency, HO2S,
injector, fuel pressure, ECT, IAT or BARO pressure sensor.
DTC P0201
Cylinder No. 1 injector circuit failure. Possible causes are:
connector or harness, or faulty injector.
DTC P0202
Cylinder No. 2 injector circuit failure. Possible causes are:
connector or harness, or faulty injector.
DTC P0203
Cylinder No. 3 injector circuit failure. Possible causes are:
connector or harness, or faulty injector.
DTC P0204
Cylinder No. 4 injector circuit failure. Possible causes are:
connector or harness, or faulty injector.
DTC P0205
Cylinder No. 5 injector circuit failure. Possible causes are:
connector or harness, or faulty injector.
DTC P0206
Cylinder No. 6 injector circuit failure. Possible causes are:
connector or harness, or faulty injector.
DTC P0300
Random misfire detected. Possible causes are: connector or
harness, faulty ignition coil, ignition power transistor, spark plug,
ignition circuit, injector, HO2S, compression pressure, timing belt,
air intake system, fuel pressure, or CKP sensor.
DTC P0301
Cylinder No. 1 misfire detected. Possible causes are:
connector or harness, faulty ignition coil, ignition power transistor,
spark plug, ignition circuit, injector, HO2S, compression pressure,
timing belt, air intake system, fuel pressure, or CKP sensor.
DTC P0302
Cylinder No. 2 misfire detected. Possible causes are:
connector or harness, faulty ignition coil, ignition power transistor,
spark plug, ignition circuit, injector, HO2S, compression pressure,
timing belt, air intake system, fuel pressure, or CKP sensor.

DTC P0303
Cylinder No. 3 misfire detected. Possible causes are:
connector or harness, faulty ignition coil, ignition power transistor,
spark plug, ignition circuit, injector, HO2S, compression pressure,
timing belt, air intake system, fuel pressure, or CKP sensor.
DTC P0304
Cylinder No. 4 misfire detected. Possible causes are:
connector or harness, faulty ignition coil, ignition power transistor,
spark plug, ignition circuit, injector, HO2S, compression pressure,
timing belt, air intake system, fuel pressure, or CKP sensor.
DTC P0305
Cylinder No. 5 misfire detected. Possible causes are:
connector or harness, faulty ignition coil, ignition power transistor,
spark plug, ignition circuit, injector, HO2S, compression pressure,
timing belt, air intake system, fuel pressure, or CKP sensor.
DTC P0306
Cylinder No. 6 misfire detected. Possible causes are:
connector or harness, faulty ignition coil, ignition power transistor,
spark plug, ignition circuit, injector, HO2S, compression pressure,
timing belt, air intake system, fuel pressure, or CKP sensor.
DTC P0325
Knock Sensor (KS) circuit failure. Possible causes are:
connector or harness, or faulty KS.
DTC P0335
Crankshaft Position (CKP) sensor circuit failure. Possible
causes are: connector or harness, or faulty CKP sensor.
DTC P0340
Camshaft Position (CMP) sensor circuit failure. Possible
causes are: connector or harness, or faulty CMP sensor.
DTC P0400
Exhaust Gas Recirculation (EGR) flow failure. Possible causes\
are: connector or harness, faulty EGR valve, EGR solenoid, EGR valve
control vacuum, or manifold differential pressure sensor.
DTC P0403
Exhaust Gas Recirculation (EGR) solenoid failure. Possible
causes are: connector or harness, or faulty EGR solenoid.
DTC P0420
Catalyst efficiency below threshold. Possible causes are:
cracked exhaust manifold, or faulty catalytic converter.
DTC P0421
Warm-up catalyst efficiency below threshold (bank 1).
Possible causes are: faulty exhaust manifold. If exhaust manifold is
okay, replace catalytic converter.
DTC P0431
Warm-up catalyst efficiency below threshold (bank 2).
Possible causes are: faulty exhaust manifold. If exhaust manifold is
okay, replace catalytic converter.
DTC P0442
Evaporative (EVAP) emission control system leak detected.
Possible causes are: connector or harness, faulty EVAP purge solenoid,

Fig. 10: Fuel Injector Terminals (Montero - Intermediate Connector)
Courtesy of Mitsubishi Motor Sales of America
Fig. 11: Fuel Injector Terminals (3000GT Non-Turbo - Rear Injector
Bank)
Courtesy of Mitsubishi Motor Sales of America

Fig. 12: Fuel Injector Terminals (3000GT Turbo - Rear Injector Bank)
Courtesy of Mitsubishi Motor Sales of America
Fig. 13: Fuel Injector Terminals (3000GT - Front Injector Bank)
Courtesy of Mitsubishi Motor Sales of America

original complaint. Recheck for DTCs. If no DTCs are displayed, go to
INTERMITTENT DTCS.
DTC P0170 & P0173: FUEL TRIM FAILURE
NOTE: For terminal identification, see TERMINAL IDENTIFICATION. For
circuit and wire color identification, see
L - WIRING DIAGRAMS article.
1) Specific self-diagnostic test not available from
manufacturer at time of publication. Check volume airflow sensor, fuel
injectors, engine coolant temperature sensor, intake air temperature
sensor, barometric or manifold absolute pressure sensor, heated oxygen
sensor. See appropriate DTC test. Check related connectors and
harnesses. See L - WIRING DIAGRAMS article.
2) Also check fuel pressure, check for intake air leaks, and
for cracked manifold. See F - BASIC TESTING article.
DTC P0201-P0206: FUEL INJECTOR CIRCUIT FAILURE
NOTE: 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 3). Using a stethoscope or
long-bladed screwdriver, listen for clicking sound from each fuel
injector while engine is running or being cranked. If no sound is
heard from fuel injector(s), check fuel injector connections. Repair
connections as necessary. If connections are okay, go to next step.
2) Ensure engine coolant temperature is at 68
F (20C).
Disconnect fuel injector connector. Using DVOM, check resistance
between specified fuel injector terminals. See
FUEL INJECTOR TERMINAL IDENTIFICATION table. If resistance is not 2.0-
3.0 3000GT turbo or 13-16 ohms on all other models, replace fuel
injector(s). If resistance is as specified, go to step 6).
FUEL INJECTOR TERMINAL IDENTIFICATION TABLE
\
\
\
\
\
\
Application Terminals No.
Montero ( 1) ........................................ 8 & 1
8 & 2
8 & 3
8 & 5
8 & 6
8 & 7
3000GT - Rear Bank ( 2)
Non-Turbo ........................................ 1 & 2
1 & 5
1 & 6
Turbo ............................................ 1 & 4
2 & 8
4 & 5
4 & 6
4 & 7
4 & 8
( 1) - Check resistance at intermediate fuel injector
connector (component side).
( 2) - Check resistance at rear fuel injector connector
(component side).
\
\
\
\
\
\

GENERAL COOLING SYSTEM SERVICING
1998 Mitsubishi Montero
GENERAL INFORMATION
General Cooling System Servicing
* PLEASE READ THIS FIRST *
The following article is for general information only.
Information may not apply to all years, makes and models. See specific
article in the ENGINE COOLING section.
DESCRIPTION
The basic liquid cooling system consists of a radiator, water
pump, thermostat, electric or belt-driven cooling fan, pressure cap,
heater, and various connecting hoses and cooling passages in the block
and cylinder head.
MAINTENANCE
DRAINING
Remove radiator cap and open heater control valve to maximum
heat position. Open drain cocks or remove plugs in bottom of radiator
and engine block. In-line engines usually have one plug or drain cock,
while "V" type engines will have 2, one in each bank of cylinders.
CLEANING
A good cleaning compound removes most rust and scale. Follow
manufacturer's instructions in the use of cleaner. If considerable
rust and scale has to be removed, cooling system should be flushed.
Clean radiator air passages with compressed air.
FLUSHING
CAUTION: Some manufacturers use an aluminum and plastic radiator.
Flushing solution must be compatible with aluminum.
Back Flushing
Back flushing is an effective means of removing cooling
system rust and scale. The radiator, engine and heater core should be
flushed separately.
Radiator
To flush radiator, connect flushing gun to water outlet of
radiator and disconnect water inlet hose. To prevent flooding engine,
use a hose connected to radiator inlet. Use air in short bursts to
prevent damage to radiator. Continue flushing until water runs clear.
Engine
To flush engine, remove thermostat and replace housing.
Connect flushing gun to water outlet of engine. Flush using short air
bursts until water runs clean.
Heater Core
Flush heater core as described for radiator. Ensure heater
control valve is set to maximum heat position before flushing heater.