Page 337 of 1501

lights, cooling fan and accessories off. Shift transmission into
Neutral or Park position.
2) If not using scan tool, go to next step. Connect scan tool
to Data Link Connector (DLC). DLC is located below dash, near steering\
column. See Fig. 2. Go to step 5).
3) On DOHC models, insert a paper clip in engine speed
detection connector. See Fig. 3. On SOHC models, insert paper clip in
noise filter connector. See Fig. 5. On all models, connect a
tachometer to paper clip.
4) Connect a jumper wire between ground and Data Link
Connector (DLC) terminal No. 1. See Fig. 2. Disconnect waterproof
female connector from Brown ignition timing check connector. See
Fig. 4 . Using a jumper wire, ground ignition timing check terminal.
5) Start engine and allow it to idle. Check basic idle speed.
See IDLE SPEED SPECIFICATIONS table. On DOHC models, multiply
tachometer reading by 3 to obtain actual basic idle speed. If idle
speed is not within specification, turn engine speed adjusting screw
until correct engine speed is obtained. See Fig. 6. Access to speed
adjusting screw is obtained by removing rubber plug on throttle body.
6) If idle speed cannot be lowered by turning engine speed
adjusting screw, determine if Throttle Position (TP) sensor has been
moved. Adjust TP sensor if necessary. See TP SENSOR ADJUSTMENT under
THROTTLE POSITION (TP) SENSOR. If TP sensor is okay, replace throttle
body.
Fig. 6: Adjusting Idle Speed (Typical)
Courtesy of Mitsubishi Motor Sales of America
IDLE SPEED SPECIFICATIONS TABLE
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Page 338 of 1501

Application Curb Idle Basic Idle
1.5L & 1.8L ............ 600-800 ............... 650-750
2.0L
Non-Turbo ............ 700-900 ................... (1)
Turbo ................ 650-850 ............... 700-800
2.4L ................... 650-850 ............... 700-800
3.0L & 3.5L ............ 600-800 ............... 650-750
( 1) - Information is not available from manufacturer at time
of publication.
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NOTE: Basic idle speed should only be adjusted after verifying
spark plugs, fuel injectors, idle air control motor and
engine compression are okay.
All Other Models
1) Ensure vehicle is at normal operating temperature with all
lights, cooling fan and accessories off. Shift transmission into
Neutral or Park position.
2) Basic idle speed can only be adjusted using a scan tool to
ground Data Link Connector (DLC). Connect scan tool to DLC. DLC is
located below dash, near steering column. See Fig. 2.
3) Start engine and allow it to idle. Using scan tool, select
MFI SYSTEM ACTUATOR TEST, then select item 30. Check basic idle speed.
See IDLE SPEED SPECIFICATIONS table.
CAUTION: MFI system actuator test must be cancelled or test will
continue to run for 27 minutes. Driving vehicle under this
condition may damage engine.
4) Cancel MFI system actuator test. If idle speed is not
within specification, turn engine speed adjusting screw until correct
engine speed is obtained. See Fig. 6. Access to speed adjusting screw
is obtained by removing rubber plug on throttle body.
5) If idle speed cannot be lowered by turning engine speed
adjusting screw, determine if fixed Speed Adjusting Screw (SAS). Fixed\
SAS is stop screw contacting throttle lever. See
FIXED SPEED ADJUSTING SCREW for procedure.
6) After all adjustments are verified to be correct, possible
cause of incorrect idle speed is deterioration of Idle Air Control
(IAC) circuit. See DTC P0505 in G - TESTS W/CODES article.
CURB (SLOW) IDLE SPEED
NOTE: Curb idle speed is controlled by Idle Air Control (IAC)
motor. Adjustment is usually not necessary. For curb idle
speed specifications, see IDLE SPEED SPECIFICATIONS table
under BASIC IDLE SPEED.
1) Check ignition timing and adjust if necessary. See
IGNITION TIMING . Run engine at 2000-3000 RPM for more than 5 seconds.
Allow engine to idle for 2 minutes. Check curb idle speed.
2) If curb idle speed is not within specification, check IAC
system. See DTC P0505 in G - TESTS W/CODES article. If IAC system is
okay, adjust basic idle speed. See BASIC IDLE SPEED.
FIXED SPEED ADJUSTING SCREW
NOTE: Fixed Speed Adjusting Screw (SAS) is preset by manufacturer
and usually does not require adjustment. Only adjust fixed
SAS if other adjustment procedures require it, or if
Page 339 of 1501

manufacturer's original setting has been changed.
1) Loosen throttle cable. Loosen fixed SAS lock nut. See
Fig. 7. Turn fixed SAS counterclockwise until throttle valve is fully
closed. Turn fixed SAS clockwise until throttle valve begins to open.
Turn fixed SAS clockwise 1 1/4 turns after throttle valve begins to
open.
2) Tighten lock nut while holding fixed SAS in position.
Adjust throttle cable. Adjust basic idle speed. See BASIC IDLE SPEED.
Adjust Throttle Position (TP) sensor. See TP SENSOR ADJUSTMENT under
THROTTLE POSITION (TP) SENSOR.
Fig. 7: Adjusting Fixed Speed Adjusting Screw (Typical)
Courtesy of Mitsubishi Motor Sales of America
IDLE MIXTURE
NOTE: Idle mixture is computer controlled on fuel injected engines
and is nonadjustable. CO level should not exceed .5%. HC
level should not exceed 100 ppm. If mixture levels exceed
limits, see G - TESTS W/CODES article.
THROTTLE POSITION (TP) SENSOR
TP SENSOR ADJUSTMENT
NOTE: Ensure basic idle speed is set to specification before
adjusting TP sensor. See BASIC IDLE SPEED under IDLE SPEED &
Page 340 of 1501

MIXTURE. Perform all adjustments with engine at normal
operating temperature, front wheels in straight-ahead
position, cooling fan and all accessories off, and
transmission in Park or Neutral.
Eclipse 2.0L Non-Turbo
1) TP sensor is not adjustable. Disconnect TP sensor
connector. Using external ohmmeter, measure resistance between TP
sensor terminals No. 1 and 3. See Fig. 8. If resistance is not 3500-
6500 ohms, replace TP sensor.
2) While slowly rotating throttle valve from idle to full
open, measure resistance between TP sensor terminals No. 2 and 3. If
resistance does not change smoothly in proportion to throttle opening,
replace TP sensor.
Montero
1) Disconnect TP sensor connector. Using jumper wires,
connect an external ohmmeter between TP sensor terminals No. 1 and 2.
See Fig. 9 . Insert .025" (.65 mm) feeler gauge between fixed speed
adjusting screw and throttle lever.
2) Loosen TP sensor mounting screws and rotate TP sensor
fully clockwise. Ensure there is continuity between terminals No. 1
and 2. Rotate TP sensor counterclockwise until there is no continuity,
and tighten screws. Install Test Harness (MB991348) between TP sensor
and harness connector.
3) Turn ignition on. Using external voltmeter, measure TP
sensor output voltage between terminals No. 1 and 3. If voltage is not
.4-1.0 volt, check harness and sensor. See DTC P0120 in G - TESTS
W/CODES article.
All Other Models
1) Disconnect TP sensor connector. Using jumper wires,
connect an external ohmmeter between TP sensor terminals No. 1 and 2
on Diamante or No. 3 and 4 on all other models. See Fig. 9. On
Diamante and Mirage 1.8L with cruise control, insert .055" (1.40mm)
feeler gauge between fixed speed adjusting screw and throttle lever.
On Galant, insert .025" (.65 mm) feeler gauge between fixed speed
adjusting screw and throttle lever. On all other models, insert .018"
(.45 mm) feeler gauge between fixed speed adjusting screw and throttle\
lever.
2) Loosen TP sensor mounting screws and rotate TP sensor
fully counterclockwise. Ensure there is continuity between terminals
No. 1 and 2 on Diamante, or No. 3 and 4 on all other models. Rotate TP
sensor clockwise until there is no continuity and tighten screws.
Install Test Harness (MB991348) between TP sensor and harness
connector.
3) Turn ignition on. Using external voltmeter, measure TP
sensor output voltage between terminals No. 1 and 3 on Diamante, or
No. 2 and 4 on all other models. If voltage is not .4-1.0 volt, check
harness and sensor. See DTC P0120 in G - TESTS W/CODES article.
Fig. 8: TP Sensor Connector Terminals (Eclipse 2.0L Non-Turbo)
Courtesy of Mitsubishi Motor Sales of America
Page 341 of 1501
Fig. 9: TP Sensor Connector Terminals (All Other Models)
Courtesy of Mitsubishi Motor Sales of America
Page 342 of 1501

DEFOGGER - REAR WINDOW
1998 Mitsubishi Montero
1998 ACCESSORIES & EQUIPMENT
Mitsubishi - Rear Window Defoggers
Diamante, Eclipse, Galant, Mirage, Montero, Montero Sport,
3000GT
DESCRIPTION & OPERATION
Rear window defogger is a heating filament grid bonded to
inside of window. Rear window defogger is controlled by defogger
switch on instrument panel and a defogger relay.
On Montero, a timer relay controls defogger operation for 9-
11 minutes, then turns defogger off. On Eclipse and Galant, defogger
timer circuit is integral with Electronic Timer Alarm Control System
(ETACS) ECU. Timer will operate defogger for 11 minutes then turn off,\
even with defogger switch in ON position and indicator light
illuminated. On Diamante, timer will operate defogger for 20 minutes,
then turn off.
COMPONENT LOCATIONS
COMPONENT LOCATIONS TABLE \
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Component Location
A/C ECU
Diamante ......................... Behind Center Of Dash
Data Link Connector (DLC) ....... Under Left Side Of Dash,
Near Steering Column
Defogger Relay
Montero Sport ....................... Under Left Side Of
Glove Compartment
Except Montero Sport ................... On Relay Block,
Behind Left Side Of Dash
Defogger Timer
Diamante ......................... Integral With A/C ECU
Eclipse & Galant ............... Integral With ETACS-ECU
Montero ...................... Behind Left Side Of Dash,
Behind Speaker
ETACS-ECU ......................... Above Left Kick Panel,
On Junction Block
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TROUBLE SHOOTING
* PLEASE READ THIS FIRST *
NOTE: For additional trouble shooting information on Eclipse and
Galant, see SYMPTOM TESTS.
DEFOGGER DOES NOT WORK
Check for blown fuse, poor contact, defective defogger
switch, poor connection or open wire.
DEFOGGER TIMER INOPERATIVE
Page 343 of 1501

Check defogger switch or defogger timer. See COMPONENT TESTS.
INDICATOR LIGHT DOES NOT WORK
Check for burned out bulb, open circuit or poor connection.
INDICATOR LIGHT IS DIM
Check rheostat or indicator bulb.
SYMPTOM TESTS
INPUT SIGNAL INSPECTION
NOTE: The following information only applies to Eclipse and Galant.
NOTE: Perform input signal inspection before proceeding with
SYSTEM TESTS .
Eclipse & Galant
1) Input signal inspection can be performed using scan tool
or an analog voltmeter. To perform inspection using scan tool, go to
next step. To perform inspection using an analog voltmeter, go to step
3).
2) Turn ignition off. Connect scan tool to Data Link
Connector (DLC). Turn ignition on and then off. If buzzer on scan tool\
sounds when ignition was turned on, ECU input signal is normal. If
buzzer did not sound, go to SYSTEM TESTS.
3) Turn ignition off. Connect DTC Check Harness (MB991529) t\
o
DLC terminals No. 4 or 5 (ground) and terminal No. 9. See Fig. 1.
Connect voltmeter leads to check harness leads. Turn ignition switch
on, then off. If voltmeter deflects once when ignition was turned on,
ECU input signal is normal. If voltmeter did not deflect, go to
SYSTEM TESTS .
Fig. 1: Identifying Data Link Connector (DLC) Terminals
Courtesy of Mitsubishi Motor Sales of America
SYSTEM TESTS
Page 344 of 1501

NOTE: The following information only applies to Eclipse and Galant.
NOTE: Perform INPUT SIGNAL INSPECTION before proceeding with
SYSTEM TESTS. To identify circuit connector terminals, see
WIRING DIAGRAMS .
Communication With All Systems Not Possible (Eclipse &
Galant)
1) Check voltage between ground and Data Link Connector (DLC)\
terminal No. 16 (Red/Black wire on Eclipse or Brown/Red wire on
Galant). See Fig. 1. If battery voltage is present, go to step 3). If
battery voltage is not present, go to next step.
2) Check junction block connectors between DLC and power
supply. See WIRING DIAGRAMS . If connectors are okay, check circuit
between power supply and DLC. See WIRING DIAGRAMS. Repair as
necessary.
3) Check continuity between ground and DLC terminals No. 4
and 5. If continuity is present, replace scan tool and retest. If
continuity is not present, check circuit between ground and DLC. See
WIRING DIAGRAMS . Repair as necessary.
Communication With One-Shot Pulse Input Signal Only Is Not
Possible (Eclipse & Galant)
Check circuit between DLC and junction block No. 1. See
WIRING DIAGRAMS . Repair as necessary. If circuit is okay, check
harness connectors to ETACS-ECU, DLC and junction/joint connectors.
Repair as necessary. If connectors are okay, replace ECU.
Defogger Does Not Operate With Defogger Switch ON (Eclipse &
Galant)
1) Check defogger switch input signal. See
INPUT SIGNAL INSPECTION . If switch input signal is okay, check
defogger circuit and relay. See DEFOGGER RELAY TEST under COMPONENT
TESTS. Repair or replace as necessary. If switch input signal is not
okay, go to next step.
2) Check defogger switch. See DEFOGGER SWITCH TEST under
COMPONENT TESTS. Replace as necessary. If defogger switch is okay,
turn ignition on. Check voltage between ground and defogger switch
harness-side connector terminal No. 4 (Eclipse) or terminal No. 2
(Galant). See WIRING DIAGRAMS . If voltage reading is 5 volts (Eclipse)
or battery voltage (Galant), go to next step. If voltage reading is
not as specified, go to step 4).
3) Check joint/junction connectors between switch, instrument
panel cluster and ETACS-ECU. See WIRING DIAGRAMS. Repair as necessary.
If connectors are okay, check circuit between defogger switch and
ground. Repair as necessary. If circuit is okay, replace ECU.
4) Check harness connectors to ETACS-ECU and instrument panel
cluster. Repair as necessary. If connectors are okay, check circuit
between ECU and defogger switch. Repair as necessary.
Defogger Relay Circuit System Check (Eclipse & Galant)
1) Check defogger relay. See DEFOGGER RELAY TEST under
COMPONENT TESTS. Replace as necessary. If relay is okay, go to next
step.
2) Check voltage between ground and relay harness-side
connector terminals No. 3 and 5. See WIRING DIAGRAMS. If battery
voltage is present, go to next step. If battery voltage is not
present, go to step 4).
3) Check harness connectors to relay, ETACS-ECU, junction
block and rear wiring/liftgate. See WIRING DIAGRAMS. Repair as
necessary. If connectors are okay, check circuit between defogger
relay and rear defogger, defogger and ground, or defogger relay and
ECU. See WIRING DIAGRAMS . Repair as necessary. If circuits are okay,