idle speed control MITSUBISHI MONTERO 1998 Owner's Manual
[x] Cancel search | Manufacturer: MITSUBISHI, Model Year: 1998, Model line: MONTERO, Model: MITSUBISHI MONTERO 1998Pages: 1501, PDF Size: 25.81 MB
Page 705 of 1501
Application Wire Color Location
Diamante .................. Black/Blue ............ (1)
Eclipse (Turbo & 2.4L) .... Black/Blue ............. ( 2)
Galant .................... Black/Blue ............ ( 3)
Mirage .................... Black/Blue ............ ( 1)
Montero ...................... White .............. ( 4)
3000GT .................... Black/Blue ............ ( 6)
( 1) - On firewall, above brake master cylinder.
( 2) - On firewall behind battery.
( 3) - On main wiring harness, near center of firewall.
( 4) - On main wiring harness, near right center of firewall.
( 5) - Near left rear corner of engine compartment, below
cruise control actuator (if equipped).
( 6) - On main wiring harness, near wiper motor on firewall,
behind battery.
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3) Start engine and allow it to idle. Measure fuel pressure
with vacuum hose connected to fuel pressure regulator. Record fuel
pressure reading. See FUEL PUMP PERFORMANCE table. Disconnect and plug
vacuum hose from fuel pressure regulator. Record fuel pressure
reading.
4) Check for fuel pressure in fuel return hose by gently
pinching hose while increasing engine speed. If fuel volume is low,
fuel pressure in return hose will not be felt. Increase engine speed
to 2500-3000 RPM, 2-3 times. Return engine to idle. Fuel pressure
should not drop when engine is returned to idle.
5) Turn ignition off. Ensure fuel pressure reading does not
decrease within 2 minutes. If a decrease is noted, monitor speed of
decrease.
6) If fuel pressure is lower than specification, fuel
pressure drops at idle after increasing engine speed to 2500-3000 RPM,
or no fuel pressure in fuel return hose can be felt, check for clogged
fuel filter, or faulty fuel pressure regulator or fuel pump.
7) If fuel pressure is greater than specification, check for
a faulty fuel pressure regulator or plugged fuel return line. If fuel
pressure does not change when vacuum hose to regulator is connected or
disconnected, check for a leaking or clogged vacuum hose to fuel
pressure regulator or faulty fuel pressure regulator.
8) If fuel pressure decreases suddenly after engine is
stopped, check valve in fuel pump is not seated. Replace fuel pump. If
fuel pressure drops slowly, fuel injector is leaking or fuel pressure
regulator valve seat is leaking. Check for faulty fuel injector or
fuel pressure regulator. Repair as necessary.
9) When fuel pressure test is complete, repeat fuel pressure
release procedure before disconnecting fuel pressure gauge. Install
NEW "O" ring at end of high pressure fuel inlet line. Check for fuel
leaks.
FUEL PUMP PERFORMANCE TABLE
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At Idle w/Vacuum At Idle w/o Vacuum
Application psi (kg/cm) psi (kg/cm)
Eclipse 2.0L
Non-Turbo ........... ( 1) ............ 47-50 (3.3-3.5)
Turbo ............. 33 (2.3) ......... 42-45 (3.0-3.5)
3000GT Turbo ........ 34 (2.4) ......... 43-45 (3.0-3.1)
All Other Models .... 38 (2.7) ......... 47-50 (3.3-3.5)
( 1) - Information is not available from manufacturer at time
Page 706 of 1501
![MITSUBISHI MONTERO 1998 Owners Manual of publication. \
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MFI CONTROL RELAY
MFI control](/img/19/57333/w960_57333-705.png "MITSUBISHI MONTERO 1998 Owners Manual of publication. \
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MFI CONTROL RELAY
MFI control")
of publication. \
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MFI CONTROL RELAY
MFI control relay switches power to vehicle sensors and
actuators including Volume Airflow (VAF) sensor, crankshaft position
sensor, idle speed control, injectors and fuel pump. When ignition
switch is turned to RUN position, PCM energizes coils controlling
injectors, VAF sensor and idle air control. When ignition switch is
turned to START position, PCM energizes coils (through park/neutral
position switch on A/T models) to supply power to fuel pump. Relay
failure will cause a no-start condition. For testing procedure, see I
- SYSTEM/COMPONENT TESTS article.
IGNITION CHECKS
* PLEASE READ THIS FIRST *
NOTE: Perform all circuit tests with a Digital Volt-Ohmmeter
(DVOM) with a minimum 10-megohm input impedance, unless
stated otherwise in test procedure.
SPARK
Check for spark at coil wire (if applicable) and at each
spark plug wire using a high output spark tester. Check spark plug
wire resistance on suspect wires. Wire resistance should not exceed
22,000 ohms for all models except Eclipse 2.0L non-turbo and Montero.
On Eclipse 2.0L non-turbo, resistance should not exceed 8000 ohms. On
Montero, resistance should not exceed 26,000 ohms.
CAMSHAFT POSITION (CMP) SENSOR
For CMP sensor testing procedure, see G - TESTS W/CODES
article.
CRANKSHAFT POSITION (CKP) SENSOR
For CKP sensor testing procedure, see G - TESTS W/CODES
article.
DISTRIBUTORLESS IGNITION SYSTEM (DIS - 4-CYLINDER)
Ignition Coil Resistance (Eclipse)
1) On Mirage 1.8L, see POWER TRANSISTOR (MIRAGE). On Eclipse\
2.0L non-turbo, go to step 3). On Eclipse 2.0L turbo and 2.4L,
disconnect ignition coil connector. Go to next step.
2) On Eclipse 2.0L turbo, use DVOM to measure primary coil
resistance between ignition coil connector terminals No. 2 and 3 (coil
for cylinders No. 1 and 4) and terminals No. 1 and 3 (coil for
cylinders No. 2 and 3). See Fig. 3. On Eclipse 2.4L, use DVOM to
measure primary coil resistance Between ignition coil terminals. Go to
step 4).
Fig. 2: Ignition Coil Connector Terminals (Eclipse 2.0L Non-Turbo)
Courtesy of Mitsubishi Motor Sales of America
Page 723 of 1501
purge control valve, or vacuum hose routing.
DTC P0443
Evaporative (EVAP) purge control valve circuit failure.
Possible causes are: connector or harness, or faulty EVAP solenoid.
DTC P0446
Evaporative (EVAP) emission control system vent control
failure. Possible causes are: connector or harness, faulty EVAP vent
solenoid.
DTC P0450
Evaporative (EVAP) emission control system pressure sensor
failure. Possible causes are: connector or harness, or faulty fuel
tank differential pressure sensor.
DTC P0455
Evaporative (EVAP) emission control system large leak
detected. Possible causes are: connector or harness, faulty EVAP purge
solenoid, purge control valve, or vacuum hose routing.
DTC P0500
Vehicle Speed Sensor (VSS) failure. Possible causes are:
connector or harness, or faulty VSS.
DTC P0505
Idle Air Control (IAC) system failure. Possible causes are:
connector or harness, or faulty IAC motor.
DTC P0510
Closed Throttle Position (TP) switch failure. Possible causes\
are: connector or harness, or faulty closed TP switch.
DTC P0551
Power Steering Pressure (PSP) sensor failure. Possible causes\
are: connector or harness, or faulty PSP sensor.
DTC P0705
Automatic transaxle/transmission range sensor circuit
failure. Possible causes are: connector or harness, or faulty PNP
switch.
DTC P0710
Automatic transaxle/transmission fluid sensor failure.
Possible causes are: connector or harness, or faulty
transaxle/transmission sensor.
DTC P0715
Automatic transaxle input/turbine speed sensor circuit
failure. Possible causes are: connector or harness, or pulse
generator.
DTC P0720
Automatic transaxle input/turbine speed sensor circuit
failure. Possible causes are: connector or harness, or pulse
generator.
DTC P0725
Engine speed input circuit failure. Possible causes are:
connector or harness.
DTC P0740
Torque converter clutch system failure. Possible causes are:
Page 757 of 1501
3) Connect an engine tachometer. Crank engine. Ensure
ignition coil primary current toggles on and off. Using scan tool,
read engine cranking speed (item 22). Compare tachometer and scan tool\
RPM display. Go to next step.
4) If engine fails to start and tachometer reads zero RPM
when engine is cranked, check for broken timing belt or faulty CKP
sensor. If CKP sensor is suspected, substitute known-good CKP sensor.
Repeat test procedure. If engine fails to start, tachometer reads zero
RPM, and ignition coil primary current fails to toggle on and off,
check for faulty ignition coil, ignition circuit or power transistor.
If engine starts and readouts agree, go to next step.
5) Ensure A/C switch is in ON position to activate closed
throttle position switch. Allow engine to idle. Using scan tool, check
engine coolant temperature and read idle speed. See
IDLE RPM SPECIFICATIONS table. If RPM is not to specification, check
for faulty ECT sensor, basic idle speed adjustment, or idle air
control motor. If RPM is within specifications, go to next step.
IDLE RPM SPECIFICATIONS TABLE
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Engine Coolant Temperature Engine RPM
-4
F (-20C)
Montero ...................................... 1300-1500
3000GT
Non-Turbo .................................. 1275-1475
Turbo ...................................... 1300-1500
32
F (0C)
Montero ...................................... 1300-1500
3000GT
Non-Turbo .................................. 1225-1425
Turbo ...................................... 1300-1500
68
F (20C)
Montero ...................................... 1300-1500
3000GT
Non-Turbo .................................. 1100-1300
Turbo ...................................... 1300-1500
104
F (40C)
Montero ...................................... 1040-1240
3000GT
Non-Turbo ................................... 950-1150
Turbo ...................................... 1050-1250
176
F (80C)
Montero & 3000GT ............................... 600-800
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6) On 3000GT, go to next step. On Montero, disconnect CKP
sensor connector and MFI relay connector. Using DVOM, check for
continuity between CKP sensor connector terminal No. 3 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) With CKP sensor connector disconnected, check for
continuity between chassis ground and CKP sensor connector terminal
No. 1 on Montero or No. 2 on 3000GT. If continuity does not exist,
repair wiring harness as necessary. If continuity exists on 3000GT, go
to next step. On Montero, go to step 9).
8) Check for voltage between chassis ground and CKP sensor
connector terminal No. 3. If battery voltage does not exist, repair
wiring harness as necessary. If battery voltage exists, go to step
10).
9) Turn ignition switch to OFF position. With CKP sensor
connector disconnected, disconnect PCM connector. Check for continuity
Page 769 of 1501
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.
Page 796 of 1501
* 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.
Page 820 of 1501
![MITSUBISHI MONTERO 1998 Owners Manual THROTTLE POSITION (TP) SWITCH or THROTTLE POSITION (TP) SENSOR in G \
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TESTS W/CODES article.
Engine Coolant Temperature Sensor
See G - TESTS W/CODES article.
Heated Oxyge](/img/19/57333/w960_57333-819.png "MITSUBISHI MONTERO 1998 Owners Manual THROTTLE POSITION (TP) SWITCH or THROTTLE POSITION (TP) SENSOR in G \
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TESTS W/CODES article.
Engine Coolant Temperature Sensor
See G - TESTS W/CODES article.
Heated Oxyge")
THROTTLE POSITION (TP) SWITCH or THROTTLE POSITION (TP) SENSOR in G \
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TESTS W/CODES article.
Engine Coolant Temperature Sensor
See G - TESTS W/CODES article.
Heated Oxygen Sensor
See G - TESTS W/CODES article.
Intake Air Temperature (IAT) Sensor
On all models except Eclipse 2.0L non-turbo and Mirage 1.5L,
IAT sensor is a part of volume airflow sensor assembly. On all models,
see G - TESTS W/CODES article.
Manifold Absolute Pressure Sensor
See G - TESTS W/CODES article.
Manifold Differential Pressure Sensor
See G - TESTS W/CODES article.
Power Steering Oil Pressure (PSP) Switch
On Eclipse 2.0L non-turbo, see DTC 115 in G - TESTS W/CODES -
NON-TURBO article. On all other models except Eclipse 2.0L non-turbo,
see G - TESTS W/CODES article.
Throttle Position Sensor
See G - TESTS W/CODES article.
Vehicle Speed Sensor
See G - TESTS W/CODES article.
Volume Airflow Sensor
See G - TESTS W/CODES article.
MOTORS, RELAYS & SOLENOIDS
MOTORS
Idle Air Control Motor
See G - TESTS W/CODES article.
RELAYS
ASD, Fuel Pump & MFI Relay
See G - TESTS W/CODES article.
Radiator Cooling Fan Control Relay (High & Low)
See G - TESTS W/CODES article.
SOLENOIDS
EGR Control Solenoid Valve
See EXHAUST GAS RECIRCULATION (EGR) under EMISSION SYSTEMS &
SUB-SYSTEMS.
EVAP Purge Control Solenoid Valve
See FUEL EVAPORATION under EMISSION SYSTEMS & SUB-SYSTEMS.
Fuel Pressure Regulator Control Solenoid Valve (Turbo Models)
See FUEL DELIVERY under FUEL SYSTEM.
Wastegate Control Solenoid Valve
Page 1391 of 1501
Low fuel pressure Test pressure regul-
ator and fuel pump,
check for restricted
lines and filters
No distributor reference Repair ignition
pulses system as necessary
Open coolant temperature Test sensor and
sensor circuit wiring
Shorted W.O.T. switch in Disconnect W.O.T.
T.P.S. switch, engine
should start
Defective ECM Replace ECM
Fuel tank residual pressure Test for fuel
valve leaks pressure drop after
shut down
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Hard Starting Disconnected hot air tube Reconnect tube and
to air cleaner test control valve
Defective Idle Air Control Test valve operation
(IAC) valve and circuit
Shorted, open or misadjusted Test and adjust or
T.P.S. replace T.P.S.
EGR valve open Test EGR valve and
control circuit
Poor Oxygen sensor signal Test for shorted or
circuit
Incorrect mixture from PCV Test PCV for flow,
system check sealing of oil
filter cap
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Poor High Speed Low fuel pump volume Faulty pump or
Operation restricted fuel
lines or filters
Poor MAP sensor signal Test MAP sensor,
vacuum hose and
wiring
Poor Oxygen sensor signal Test for shorted or
open sensor or
circuit
Open coolant temperature Test sensor and
sensor circuit wiring
Faulty ignition operation Check wires for
cracks or poor con-
nections, test
secondary voltage
with oscilloscope
Contaminated fuel Test fuel for water
Page 1420 of 1501
Reaction ring sticking See POWER STEERING GEAR
in housing head article
Steering pump internal See POWER STEERING PUMP
leakage article
Steering gear-to-column See STEERING COLUMN
misalignment article
Lack of lubrication in Service front suspension
linkage
Lack of lubrication in Service front suspension
ball joints
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Increased Effort High internal pump leakage See POWER STEERING PUMP
When Turning article
Wheel Fast Power steering pump belt Adjust or replace if
Foaming, Milky slipping necessary
Power Steering
Fluid, Low Fluid Low fluid level Check and fill to
Level or Low proper level
Pressure
Engine idle speed to low Adjust to correct
setting
Air in pump fluid system See POWER STEERING PUMP
article
Pump output low See POWER STEERING PUMP
article
Steering gear See POWER STEERING GEAR
malfunctioning article
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Wheel Surges Low fluid level Check and fill to proper
or Jerks level
Loose fan belt Adjust or replace if
necessary
Insufficient pump See POWER STEERING PUMP
pressure article
Sticky flow control valve See POWER STEERING PUMP
article
Linkage hitting oil pan Replace bent components
at full turn
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Kick Back or Air in pump fluid system See POWER STEERING PUMP
Free Play article
Worn poppet valve in See POWER STEERING PUMP
steering gear article
Excessive over center See POWER STEERING GEAR
lash article
Thrust bearing out of See POWER STEERING GEAR
adjustment article
Page 1454 of 1501
![MITSUBISHI MONTERO 1998 Owners Manual Fig. 22: Single Injector - Known Good - Voltage Pattern
EXAMPLE #5 - CURRENT CONTROLLED DRIVER
These two known-good waveform patterns are from a Chrysler 3.
0L V6 VIN [3]. The firs](/img/19/57333/w960_57333-1453.png "MITSUBISHI MONTERO 1998 Owners Manual Fig. 22: Single Injector - Known Good - Voltage Pattern
EXAMPLE #5 - CURRENT CONTROLLED DRIVER
These two known-good waveform patterns are from a Chrysler 3.
0L V6 VIN [3]. The firs")
Fig. 22: Single Injector - Known Good - Voltage Pattern
EXAMPLE #5 - CURRENT CONTROLLED DRIVER
These two known-good waveform patterns are from a Chrysler 3.
0L V6 VIN [3]. The first waveform, Fig. 23, is a dual trace pattern
that illustrates how Chrysler uses the rising edge of the engine speed
signal to trigger the injectors. The second waveform, Fig. 24, was
taken during hot idle, closed loop, and no load.