relay MITSUBISHI MONTERO 1991 Repair Manual

motor to increase idle speed. To prevent A/C compressor from switching
on before idle speed has increased, ECU momentarily opens A/C relay
circuit.
Idle Speed Control (ISC) Motor
Controls pintle-type air valve (DOHC engines) or throttle
plate angle (SOHC engines) to regulate volume of intake air at idle.
During start mode, ECU controls idle intake air volume
according to coolant temperature input. After starting, with idle
position switch activated (throttle closed), fast idle speed is
controlled by ISC motor and fast idle air control valve (if equipped).\
When idle switch is deactivated (throttle open), ISC motor
moves to a preset position in accordance with coolant temperature
input.
When automatic transmission (if equipped) is shifted from
Neutral to Drive, A/C is turned on or power steering pressure reaches
a preset value, ECU signals ISC motor to increase engine RPM.
Fast Idle Air Control Valve
Some models use a coolant temperature-sensitive fast idle air
control valve, located on throttle body, to admit additional intake
air volume during engine warm-up. Control valve closes as temperature
increases, restricting by-pass airflow rate. At engine warm-up, valve
closes completely.
IGNITION SYSTEMS
DIRECT IGNITION SYSTEM (DIS) - DOHC ENGINES
Ignition system is a 2-coil, distributorless ignition system.
Crankshaft angle and TDC sensor assembly, mounted in place of
distributor, are optically controlled.
Power Transistors & Ignition Coils
Based on crankshaft angle and TDC sensor inputs, ECU controls
timing and directly activates each power transistor to fire coils.
Power transistor "A" controls primary current of ignition coil "A" to
fire spark plugs on cylinders No. 1 and 4 at the same time. Power
transistor "B" controls primary current of ignition coil "B" to fire
spark plugs on cylinders No. 2 and 3 at the same time.
Although each coil fires 2 plugs at the same time, ignition
takes place in only one cylinder since the other cylinder is on its
exhaust stroke when plug fires.
ELECTRONIC IGNITION SYSTEM - SOHC ENGINES
Mitsubishi breakerless electronic ignition system uses a disc
and optical sensing unit to trigger power transistor.
Power Transistor & Ignition Coil
Power transistor is mounted inside distributor with disc and
optical sensing unit. When ignition is on, ignition coil primary
circuit is energized. As distributor shaft rotates, disc rotates,
triggering optical sensing unit. ECU receives signals from optical
sensing unit. Signals are converted and sent to power transistor,
interrupting primary current flow and inducing secondary voltage.
IGNITION TIMING CONTROL SYSTEM
Ignition timing is controlled by ECU. ECU adjusts timing
based upon various conditions, such as engine temperature, altitude
and detonation (turbo vehicles only).





 







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 OK   NOT OK  




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* Check Pick-Up coil for   * Adjust or replace as  

correct resistance value.   necessary.  










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NOT OK   OK  








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* Replace Pick-Up coil if   * Check control module for  

not to specification.   good ground connections.  










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OK  




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* If vehicle fails to run at this point, go to  
 the appropriate article in the ENGINE  
 PERFORMANCE section.  









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OK   NOT OK 




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* Check wires from the battery/  * Replace ballast resistor 

ignition switch to the coil.   if the measured resistance 

Also check the coil primary   value is not within 

and secondary resistance.   specification. 










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STARTER TROUBLE SHOOTING
NOTE: This is GENERAL information. This article is not intended
to be specific to any unique situation or individual vehicle
configuration. The purpose of this Trouble Shooting
information is to provide a list of common causes to
problem symptoms. For model-specific Trouble Shooting,
refer to SUBJECT, DIAGNOSTIC, or TESTING articles available
in the section(s) you are accessing.
BASIC STARTER TROUBLE SHOOTING CHART









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CONDITION POSSIBLE CAUSE CORRECTION








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Starter Fails Dead battery or bad Check battery charge
to Operate connections between and all wires and
starter and battery connections to starter
Ignition switch faulty Adjust or replace
or misadjusted ignition switch
Open circuit between Check and repair wires
starter switch ignition and connections as
terminal on starter relay necessary
Starter relay or starter See Testing in STARTER
defective article

Engine overheated See ENGINE COOLING
SYSTEM article
Engine oil too heavy Check that proper
viscosity oil
is used
Poor battery-to-starter Check that all
connections between
battery and starter are
clean and tight
Current draw too low or See Bench Tests in
too high STARTER article
Bent armature, loose pole See STARTER article
shoes screws or worn
bearings
Burned solenoid contacts Replace solenoid
Faulty starter Replace starter









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Starter Engages Engine timing too far See Ignition Timing in
Engine Only advanced TUNE-UP article
Momentarily
Overrunning clutch not Replace overrunning
engaging properly clutch. See STARTER
article
Broken starter clutch See STARTER article
Broken teeth on engine Replace flywheel and
flywheel check starter pinion
gear for damage
Weak drive assembly See STARTER article
thrust spring
Weak hold-in coil See Bench Tests in
STARTER article









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Starter Drive Defective point assembly See Testing in STARTER
Will Not Engage article
Poor point assembly ground See Testing in STARTER
article
Defective pull-in coil Replace starter
solenoid









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Starter Relay Dead battery Charge or replace
Does Not Close battery as necessary
Faulty wiring Check all wiring and
connections leading to
relay
Neutral safety switch Replace neutral safety
faulty switch
Starter relay faulty Replace starter relay

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Starter Drive Starter motor loose on Tighten starter
Will Not mountings attach bolts
Disengage
Worn drive end bushing See STARTER article
Damaged engine flywheel Replace flywheel and
teeth starter pinion gear for
damage
Drive yolk return spring Replace return spring
broken or missing
Faulty ignition switch Replace ignition switch
Insufficient clearance Replace starter
between winding leads to solenoid
solenoid terminal and main
contact in solenoid
Starter clutch not Replace starter clutch
disengaging
Ignition starter switch Replace ignition switch
contacts sticking









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Starter Relay Faulty solenoid switch, Check all wiring
Operates but switch connections or between relay and
Solenoid Does Not solenoid or replace
relay or solenoid as
necessary
Broken lead or loose Repair wire or wire
soldered connections connections as
necessary









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Solenoid Plunger Weak battery Charge or replace
Vibrates When battery as necessary
Switch is Engaged
Solenoid contacts Clean contacts or
corroded replace solenoid
Faulty wiring Check all wiring
leading to solenoid
Broken connections inside Repair connections or
switch cover replace solenoid
Open hold-in wire Replace solenoid









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Low Current Draw Worn brushes or weak Replace brushes or
brush springs as
necessary









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High Pitched Whine Distance too great Align starter or check
During Cranking between starter that correct starter
Before Engine pinion and flywheel and flywheel are being
Fires but Engine used
Fires and Cranks
Normally









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High Pitched Distance too small between
Whine After Engine starter pinion and flywheel

problem symptoms. For model-specific Trouble Shooting,
refer to DIAGNOSTIC, or TESTING articles available in the
section(s) you are accessing.
BASIC HEATER SYSTEM TROUBLE SHOOTING CHART









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CONDITION POSSIBLE CAUSE








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Insufficient, Erratic,
or No Heat
Low Coolant Level

Incorrect thermostat.

Restricted coolant flow through
heater core.


Heater hoses plugged.

Misadjusted control cable.

Sticking heater control valve.

Vacuum hose leaking.

Vacuum hose blocked.

Vacuum motors inoperative.

Blocked air inlet.

Inoperative heater blower motor.

Oil residue on heater core fins.

Dirt on heater core fins.








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Too Much Heat
Improperly adjusted cables.

Sticking heater control valve.

No vacuum to heater control valve.

Temperature door stuck open.








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Air Flow Changes During
Acceleration
Vacuum system leak.

Bad check valve or reservoir.








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Air From Defroster At All
Times
Vacuum system leak.

Improperly adjusted control cables.

Inoperative vacuum motor.








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Blower Does Not Operate
Correctly
Blown fuse.

Blower motor windings open.

Resistors burned out.

Motor ground connection loose.

Wiring harness connections loose.

Blower motor switch inoperative.

Blower relay inoperative.

Fan binding or foreign object
in housing.


Fan blades broken or bent.








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BRAKES
BRAKE SYSTEM TROUBLE SHOOTING
NOTE: This is GENERAL information. This article is not intended
to be specific to any unique situation or individual vehicle
configuration. The purpose of this Trouble Shooting
information is to provide a list of common causes to
problem symptoms. For model-specific Trouble Shooting,
refer to SUBJECT, DIAGNOSTIC, or TESTING articles available
in the section(s) you are accessing.

Water Pump Malfunction Replace Water Pump
Fan Clutch Malfunction Replace Fan Clutch
Retarded Ignition Timing Reset Ignition Timing
Cooling Fan Malfunction Test Cooling Fan/
Circuit
Cooling Fan Motor
Malfunction Test Fan Motor
Cooling Fan Relay
Malfunction Test Fan Relay
Faulty Radiator Cap Replace Radiator Cap
Broken/Slipping Fan Belt Replace Fan Belt
Restricted Exhaust Repair Exhaust System









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Corrosion Impurities In Coolant Clean/Flush System








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Coolant Leakage Damaged hose Replace Hose
Leaky Water Pump Replace Water Pump
Damaged Radiator Seam Replace/Repair Radiator
Leaky Thermostat Cover Replace Thermostat
Cover
Cylinder Head Problem Check Head/Head Gasket
Leaky Freeze Plugs Replace Freeze Plugs









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Recovery System Inoperative
Loose and/or Defective
Radiator Cap Replace Radiator Cap
Overflow Tube Clogged
and/or Leaking Repair Tube
Recovery Bottle Vent
Restricted Clean Vent









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No Heater Core Flow
Collapsed Heater Hose Replace Heater Hose
Plugged Heater Core Clean/Replace Heater
Core
Faulty Heater Valve Replace Heater Valve









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GASOLINE ENGINE - MECHANICAL TROUBLE SHOOTING
NOTE: This is GENERAL information. This article is not intended
to be specific to any unique situation or individual vehicle
configuration. The purpose of this Trouble Shooting
information is to provide a list of common causes to
problem symptoms. For model-specific Trouble Shooting,
refer to SUBJECT, DIAGNOSTIC, or TESTING articles available

Incorrect injector pump Check pressure, see
housing pressure FUEL SYSTEMS









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Engine Cooling system leaks Check cooling system
Overheating and repair leaks
Belt slipping or damaged Check tension and/or
replace belt
Thermostat stuck closed Remove and replace
thermostat, see
ENGINE COOLING
Head gasket leaking Replace head gasket









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Oil Light on at Low oil pump pressure Check oil pump
Idle operation, see ENGINES
Oil cooler or line Remove restriction
restricted and/or replace cooler









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Engine Won't Injector pump fuel solenoid Remove and check
Shut Off does not return fuel valve solenoid and replace
to OFF position if needed









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VACUUM PUMP DIAGNOSIS
Excessive Noise Loose pump-to-drive Tighten screws
assembly screws
Loose tube on pump assembly Tighten tube
Valves not functioning Replace valves
properly
Oil Leakage Loose end plug Tighten end plug
Bad seal crimp Remove and re-crimp
seal









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FUEL INJECTION TROUBLE SHOOTING
NOTE: This is GENERAL information. This article is not intended
to be specific to any unique situation or individual vehicle
configuration. The purpose of this Trouble Shooting
information is to provide a list of common causes to
problem symptoms. For model-specific Trouble Shooting,
refer to SUBJECT, DIAGNOSTIC, or TESTING articles available
in the section(s) you are accessing.
BASIC FUEL INJECTION TROUBLE SHOOTING CHART









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CONDITION POSSIBLE CAUSE CORRECTION








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Engine Won't Cold start valve inoperative Test valve and
Start (Cranks circuit
Normally)
Poor connection;vacuum or Check vacuum and
wiring electrical
connections
Contaminated fuel Test fuel for water
or alcohol
Defective fuel pump relay Test relay and
or circuit wiring
Battery too low Charge and test
battery

Ignition switch faulty Adjust or replace
or misadjusted ignition switch
Open circuit between Check and repair wires
starter switch ignition and connections as
terminal on starter relay necessary
Starter relay or starter See Testing in STARTER
defective article
Open solenoid pull-in See Testing in STARTER
wire article









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Starter Does Not Weak battery or dead Charge or replace
Operate and cell battery as necessary
Headlights Dim
Loose or corroded battery Check that battery
connections connections are clean
and tight
Internal ground in See Testing in STARTER
starter windings article
Grounded starter fields See Testing in STARTERS
Armature rubbing on pole See STARTER article
shoes









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Starter Turns Starter clutch slipping See STARTER article
but Engine
Does Not Rotate
Broken clutch housing See STARTER article
Pinion shaft rusted or See STARTER article
dry
Engine basic timing See Ignition Timing in
incorrect TUNE-UP article
Broken teeth on engine Replace flywheel and
flywheel check for starter pinion
gear damage









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Starter Will Not Faulty overrunning See STARTER article
Crank Engine clutch
Broken clutch housing See STARTER article
Broken flywheel teeth Replace flywheel and
check for starter pinion
gear damage
Armature shaft sheared See STARTER article
or reduction gear teeth
stripped
Weak battery Charge or replace
battery as necessary
Faulty solenoid See On-Vehicle Tests in
STARTER article
Poor grounds Check all ground

connections for
tight and clean
connections
Ignition switch faulty Adjust or replace
or misadjusted ignition switch as
necessary









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Starter Cranks Battery weak or Charge or replace
Engine Slowly defective battery as necessary
Engine overheated See ENGINE COOLING
SYSTEM article
Engine oil too heavy Check that proper
viscosity oil
is used
Poor battery-to-starter Check that all
connections between
battery and starter are
clean and tight
Current draw too low or See Bench Tests in
too high STARTER article
Bent armature, loose pole See STARTER article
shoes screws or worn
bearings
Burned solenoid contacts Replace solenoid
Faulty starter Replace starter









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Starter Engages Engine timing too far See Ignition Timing in
Engine Only advanced TUNE-UP article
Momentarily
Overrunning clutch not Replace overrunning
engaging properly clutch. See STARTER
article
Broken starter clutch See STARTER article
Broken teeth on engine Replace flywheel and
flywheel check starter pinion
gear for damage
Weak drive assembly See STARTER article
thrust spring
Weak hold-in coil See Bench Tests in
STARTER article









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Starter Drive Defective point assembly See Testing in STARTER
Will Not Engage article
Poor point assembly ground See Testing in STARTER
article
Defective pull-in coil Replace starter
solenoid









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Starter Relay Dead battery Charge or replace

Does Not Close battery as necessary
Faulty wiring Check all wiring and
connections leading to
relay
Neutral safety switch Replace neutral safety
faulty switch
Starter relay faulty Replace starter relay









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Starter Drive Starter motor loose on Tighten starter
Will Not mountings attach bolts
Disengage
Worn drive end bushing See STARTER article
Damaged engine flywheel Replace flywheel and
teeth starter pinion gear for
damage
Drive yolk return spring Replace return spring
broken or missing
Faulty ignition switch Replace ignition switch
Insufficient clearance Replace starter
between winding leads to solenoid
solenoid terminal and main
contact in solenoid
Starter clutch not Replace starter clutch
disengaging
Ignition starter switch Replace ignition switch
contacts sticking









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Starter Relay Faulty solenoid switch, Check all wiring
Operates but switch connections or between relay and
Solenoid Does Not solenoid or replace
relay or solenoid as
necessary
Broken lead or loose Repair wire or wire
soldered connections connections as
necessary









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Solenoid Plunger Weak battery Charge or replace
Vibrates When battery as necessary
Switch is Engaged
Solenoid contacts Clean contacts or
corroded replace solenoid
Faulty wiring Check all wiring
leading to solenoid
Broken connections inside Repair connections or
switch cover replace solenoid
Open hold-in wire Replace solenoid









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Low Current Draw Worn brushes or weak Replace brushes or
brush springs as
necessary