ALL MODE 4X4 SYSTEM
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ALL MODE 4X4 SYSTEMPFP:47850
PrecautionsEDS000IV
lThis section describes ESP/TCS/ABS model.
lRefer to the BRC section for model without ESP/TCS/ABS.Refer toBRC-6, "ALL MODE 4X4 SYSTEM"
System ComponentEDS000IJ
System DescriptionEDS000IK
ERECTRONIC COUPLING
lIn response to command current from 4WD control unit, control
clutch pull-in force is generated at the electromagnet and torque
is generated at the control clutch.
lThe cam operates in response to control clutch torque and
applies pressure to main clutch.
lMain clutch transmits torque from input shaft to output shaft,
according to the amount of pressure.
lThe actual amount of torque transfer is determined by control
current as shown in figure below (I-T characteristics figure).
4WD CONTROL UNIT
lControls distribution of drive power between front-wheel drive
(100:0) and 4WD (50:50) conditions circuit according to signals
from sensors.
lIf malfunction occurs in 4WD system, 4WD warning lamp turns
ON and vehicle changes to front-wheel drive.
lSelf-diagnosis can be done with CONSULT-II.
SFIA0283E
SFIA0284E
SFIA0285E
SFIA0286E
TF-32
ALL MODE 4X4 SYSTEM
4WD MODE SWITCT
AUTO mode (AUTO indicator lamp ON)
lElectronic control allows optimal distribution of torque to front/rear wheels to match road conditions.
lMakes possible stable driving, with no wheel spin, on snowy roads or other slippery surfaces.
lOn roads which do not require 4WD, it contributes to improved fuel economy by driving in conditions close
to front-wheel drive.
lSensors determine the vehicle's turning condition, and in response tight cornering/braking are controlled
by distributing optimum torque to rear wheels.
NOTE:
lWhen driving in AUTO mode or LOCK mode, if there is a large difference between front and rear wheel
speed which continues for a long time, oil temperature of drive system parts becomes too high and 4WD
warning lamp flashes rapidly. (When 4WD warning lamp flashes, vehicle changes to front-wheel drive
conditions.)
lWhen driving in AUTO mode, 4WD warning lamp may flash slowly if there is a significant difference in
pressure or wear between tires. At this time, vehicle performance is not fully available and cautious driving
is required. (Continues until engine is turned OFF.)
lIf 4WD warning lamp is flashing rapidly, stop vehicle and allow it to idle for some time. Flashing will stop
and AUTO mode will be restored.
lIf the warning lamp flashes slowly during driving but remains OFF after engine is restarted, the system is
normal. If it again flashes slowly after driving for some time, vehicle must be inspected.
lWhen the difference of revolution speed between the front and rear wheel with AUTO mode the shift
switch occasionally changes to LOCK mode automatically. This is not malfunction.
LOCK mode (LOCK indicator lamp and AUTO indicator lamp ON)
lFront/rear wheel torque distribution is fixed, ensuring stable driving when climbing slopes.
lWhen LOCK mode is selected, vehicle will switch automatically to AUTO mode if vehicle speed increases.
If vehicle speed then decreases, the vehicle automatically returns to direct 4-wheel driving conditions.
NOTE:
If there is a significant difference in pressure or wear between tires, full vehicle performance is not available.
Tire conditions are detected, and LOCK mode may be prohibited, or else speeds at which LOCK mode is
enabled may be restricted.
2WD mode (indicator lamps OFF)
Vehicle is in front-wheel drive.
NOTE:
lIf front wheels are slipping in 2WD mode, do not switch to AUTO or LOCK. This can cause difficulties for
the system.
lThe shift switch even if the shift switch is in 2WD mode, the sift switch occasionally automatically change
to 4WD mode depending on the driving condition (For example; Depressing the acceleration firmly). this is
not malfunction. How ever, 4WD mode indicator lamp dose not illuminate.
4WD WARNING LAMP
Turns ON when there is a malfunction in 4WD system. It indicates that fail-safe mode is engaged and vehicle
is in 2WD.
Also turns ON when ignition switch is turned ON, for purpose of bulb check. Turns OFF approximately for 3
seconds after the engine starts if system is normal.
4WD waning lamp indiction
Condition Display 4WD warning lamp
Self-diagnosisWhen self-diagnosis is performed, indicates location of
malfunction by number of flashes.-
Lamp checkTurns ON when engine is started to check for burned-out
lamps.Turns ON when ignition switch
is turned ON. Turns OFF
approximately 3 seconds after
engine start.
4WD system malfunction Turns ON if there is malfunction in 4WD system. ON
TROUBLE DIAGNOSIS
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Trouble diagnosis chart by symptomEDS0 00 IT
Symptom Condition Check items Reference page
When ignition switch is turned ON,
4WD mode indicator lamp does not
illuminate for approx. 1 second (4WD
mode lamp check)IGN-ON
lBlown 4WD mode indicator lamp bulb
lBlown fuse between ignition and 4WD mode
indicator lamp
lOpen circuit in wiring between ignition and
4WD mode indicator lampTF-54, "
4WD
INDICATOR
LAMP DOSE
NOT COME ON
FOR APPROXI-
MATELY 1
SECOND
WHEN THE
IGNITION
SWITCH IS
TURNED TO
ON"
4WD warning lamp does not illuminate
with ignition switch ON.IGN-ON
lMalfunction 4WD warning lamp circuit.
lBlown fuse between ignition and 4WD warn-
ing lamp
lOpen circuit in wiring between ignition and
4WD warning lamp
lOpen circuit in wiring between 4WD warning
lamp and 4WD actuator relay
lDisconnected 4WD actuator relay
lOpen circuit in wiring between 4WD actuator
relay and body groundTF-55, "
4WD
WAR NIN G
LAMP DOES
NOT ILLUMI-
NATE WITH
IGNITION ON"
4WD warning lamp does not go out
several seconds after engine is started.
(4WD mode indicator lamp goes out.)Engine runningl4WD control unit connector disconnected
lMalfunction presented in 4WD systemTF-55, "
4WD
WAR NIN G
LAMP DOES
NOT GO OUT
SEVERAL SEC-
ONDS AFTER
ENGINE
STARTED.(4W
DMODEINDI-
CATOR LAMP
GOES OUT)"
Heavy tight-corner braking symptom
occurs when vehicle is driven in the fol-
lowing conditions: AUTO mode and
steering wheel is turned fully to either
sides after engine is started (Note 1,
Note 2).lEngine running
lAUTO mode
lSteering wheel
fully turned
lOperation is not in AUTO mode (in 2WD or
LOCK mode).
lThrottle position signal error
lMechanical malfunction of electronically con-
trolled coupling
lMalfunction present in 4WD systemTF-56, "
HEAVY
TIGHT-COR-
NER BRAKING
SYMPTOM
OCCURS
WHEN THE
VEHICLE IS
DRIVEN IN
AUTO MODE
AND THE
STEERING
WHEEL IS
TURNED
FULLY TO
EITHER SIDE
AFTER THE
ENGINE IS
STARTED"
4WD mode cannot be switched after
engine is started (Note 3)Engine running
l4WD mode change-over switch is discon-
nected.
lOpen circuit between 4WD mode change-
over switch and 4WD control unit
lOpen circuit between 4WD mode change-
over switch and body groundTF-57, "
4WD
MODES CAN-
NOT BE
SWITCHED
AFTER
ENGINE IS
STARTED"
TF-42
TROUBLE DIAGNOSIS
NOTE:
1. Light tight-corner braking symptom may occur depending on driving conditions in AUTO mode. This is not
malfunction.
2. Heavy tight-corner braking symptom occurs when vehicle is driven in the following conditions: LOCK
mode, steering wheel is turned fully to either sides, and accelerator pedal was depressed.
3. When the difference of revolution speed between the front and the rear wheels is large, the 4WD mode
does not change to other mode.this is not a malfunction.
4WD control unit input/output signal standardEDS000H9
4WD CONTROL UNIT CONNECTOR TERMINAL ARRANGEMENT
When ignition switch is turned to ON with connectors of 4WD control unit connected.
While driving, 4WD warning lamp
flashes rapidly. (when it flashes for
approx. one minute, then does not illu-
minate.) Rapid flashing: Two times
flashing per 1 secondEngine running
(to other than 2WD
mode)Protection function was activated due to heavy
load to electronically controlled coupling. (4WD
system is not malfunctioning.)TF-57, "
WHILE
DRIVING, 4WD
WARN ING
LAMP
FLASHES RAP-
IDLY. (WHEN IT
FLASHERS
FOR APPROX.
ONE MINUTE,
THEN DOES
NOT ILLUMI-
NATE.)"
While driving, 4WD warning lamp
flashes slowly. (when it flashes for
approx. one minute, then does not illu-
minate.)Slow flashing: One flashing
per 2 secondslEngine running
lDriving at vehicle
speed 20km/
h(12MPH)Tire size is different for front and rear of vehicle.TF-58, "
WHILE
DRIVING, 4WD
WARN ING
LAMP
FLASHES
SLOWLY.
(WHEN IT
CONTINUES
TO ILLUMI-
NATE UNTIL
ENGINE
TURNS OFF.)"
Vehicle does not enter 4WD mode
even though 4WD warning lamp is off.Engine runningMechanical malfunction of electronically con-
trolled coupling (Mechanical engagement of
clutch is not possible.)TF-58, "
VEHI-
CLE DOES
NOT ENTER
4WD MODE
EVEN
THOUGH 4WD
WARN ING
LAMP IS OFF."
Symptom Condition Check items Reference page
SDIA0120E
TF-44
TROUBLE DIAGNOSIS
Specifications defined by CONSULT-II
Check air pressure of tire under normal condition.Items to be monitored ContentsData monitor
(Reference)
Check points when result
was malfunctioning ConditionReference values in
normal operation
DECEL G-SENSOR (G)G-sensor operating
conditionWith vehicle stopped
on flat road.±0.15 G G-sensor and harness
THRTL POS SEN (V)Throttle valve open/
close conditionClosed throttle to wide
open throttleWhen closed throttle:
Approx. 0.5V
Throttle position sensor
and harness
When wide open throt-
tle: Approx. 4.0 V
ENGINE SPEED SIG
(STOP/RUN)With engine runningEngine speed below
400 rpmSTOP
Engine speed signal circuit
Engine speed 400 rpm
or higherRUN
E-TS ACTUATOR (ON/OFF)4WD actuator relay
(4WD actuator relay)
activation conditionVehicle stop (Ignition
switch ON)OFF4WD actuator relay (4WD
actuator relay) and har-
ness
Engine running ON
G-SEN VOLT (V)G-sensor power sup-
ply conditionWith vehicle stopped
on flat road.Approx. 8V (reference
value)G-sensor and harness
BATTERY VOL (V)Battery voltage sup-
plied to control unitIgnition switch ON Approx. 10 - 16 VControl unit power supply
circuit
4WDWARNLAMP(ON/
OFF)4WD warning lamp
ON condition4WD warning lamp
ONON4WD warning lamp and
harness
Refer to "4WD Warning
Lamp". 4WD warning lamp
OFFOFF
4WD MODE SW
(AUTO LOCK 2WD)Input condition of
4WD mode change-
over switchEngine running, vehi-
cle stopped, switch
pressed–4WD mode change-over
switch and circuit
4WD MODE MONI (AUTO,
LOCK, 2WD)Output condition of
4WD mode indicator
lamp signalEngine running, vehi-
cle stoppedUsing 4WD mode
change-over switch4WD mode indicator lamp
and circuit
DIS-TIRE MONI (mm)Improper size tire
installed condition–0-4mm,4-8mm,
8mm -Front/Rear tire size differ-
ence, wear condition
PBRAKESW(ON/OFF)Parking brake switch
operating conditionParking brake
depressedON
Parking brake switch and
harness
Parking brake not
depressedOFF
SPEED MTR O/P (km/h)Output condition of
vehicle speed for
speedometerWhile vehicle is
stopped0km/h(0MPH)
Speedometer and harness
Vehicle runningAlmost in accordance
with the wheel speed
sensor display
ABS 4WD COMMEPS/TCS/ABS con-
trol unit operating con-
ditionIgnition switch ON OKESP/TCS/ABS control unit
and circuit
CAN COMM (OK-NG)CAN communication
signal conditionIgnition switch ON OKCAN communication sig-
nal (OK-NG) condition is
displayed
TROUBLE DIAGNOSIS
TF-57
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3.INSPECTION USING 4WD MODE CHANGE-OVER SWITCH
lOn data monitor screen of the CONSULT-II, check 4WD mode switch.
lCheck if the display changes from ## to 2WD mode when the 2WD switch is pressed.
lCheck if the display changes from ## to AUTO mode when the AUTO switch is pressed.
lCheck if the display changes from ## to LOCK mode when the LOCK switch is pressed.
OK or NG
OK >> No malfunction detected.
NG >>
lNot in AUTO mode. (in 2WD or LOCK mode)
Countermeasure: Slightly depress the accelerator pedal and check that the operation mode
changes to LOCK mode.
lCheck circuit between 4WD mode switch harness connector M39 terminal No.1 (BR) and
4WD control unit harness connector E122 terminal No. 27 (BR).
(AUTO mode is not available because a malfunction is present in the 2WD mode harness.)
NOTICE:
Mechanism of 4WD mode change-over
l2WD mode: Operation changes to 2WD mode when 4WD control unit harness connector E122
terminal No. 27 (BR) is shorted to ground.
lAUTO mode: Operation changes to AUTO mode when 4WD control unit harness connector
E122 terminals No. 27 (BR) and No. 26 (L) is shorted to ground.
lLOCK mode: Operation changes to LOCK mode when 4WD control unit harness connector
E122 terminal No. 26 (L) is shorted to ground.
4WD MODES CANNOT BE SWITCHED AFTER ENGINE IS STARTED
1.INSPECTION USING 4WD MODE CHANGE-OVER SWITCH
lDrive modes cannot be switched after the engine is started.
lOn data monitor screen of the CONSULT-II, check 4WD mode switch.
lCheck if the display changes from ## to 2WD mode when the 2WD switch is pressed.
lCheck if the display changes from ## to AUTO mode when the AUTO switch is pressed.
lCheck if the display changes from ## to LOCK mode when the LOCK switch is pressed.
OK or NG
OK >> No malfunction detected.
NG >>
lCONSULT-II display does not change from ## when the 2WD switch is pressed. Check harness
of the 2WD switch.
lCONSULT-II display does not change from ## when the AUTO switch is pressed. Check har-
ness of the 2WD switch and LOCK switch.
lCONSULT-II display does not change from ## when the LOCK switch is pressed. Check har-
ness of the LOCK switch.
lPerform 4WD mode change-over switch inspection.
WHILE DRIVING, 4WD WARNING LAMP FLASHES RAPIDLY. (WHEN IT FLASHERS FOR
APPROX. ONE MINUTE, THEN DOES NOT ILLUMINATE.)
lWhile driving, 4WD warning lamp flashes rapidly. (when it flashes for approx. one minute, then does not
illuminate.)
Rapid flashing: 2 times/second
This phenomenon protects drivetrain parts when a heavy load is applied to the electronically controlled
coupling and multiple disc clutch temperature increases. It is not a malfunction.
When the difference of diameters by or with the front and rear wheel with AUTO mode the shift switch
occasionally changes to LOCK mode automatically. This is not a malfunction.
When the difference of revolution speed between the front and rear wheel with AUTO mode, the shift
switch occasionally changes to LOCK mode automatically. This is not a malfunction.