TF-18
4WD SYSTEM
System Diagram
EDS0031M
COMPONENTS FUNCTION
SDIA3416E
Component parts Function
Transfer control unit Controls transfer control device and switches 4HÛ4LO under 4WD condition and 2WDÛ4WD.
Transfer control device Actuator motor and actuator position switch are integrated so as to switch driving modes.
Actuator motor Controls shift rod by signals from transfer control unit.
Actuator position switch Detects actuator motor position.
Wait detection switch Detects that transfer is under 4WD condition.
4LO switch Detects that transfer is under 4LO condition.
AT P s w i t c h
(A/T models)Detects that transfer is under neutral condition.
4WD shift switch Able to select from 2WD, 4H or 4LO.
4WD warning lamp
lIlluminates if malfunction is detected in electrical system of 4WD system.
lThere is 1 blink in 2 seconds if rotation difference of front wheels and rear wheels is large.
ATP warning lamp
(A/T models)Indicates that A/T parking mechanism does not operate when A/T selector lever is in “P” position
and transfer is under neutral condition.
4WD shift indicator lamp Displays driving condition selected by 4WD shift switch.
4LO indicator lamp Displays 4LO condition.
PNP switch
(M/T models)Detects that manual transmission is under neutral condition.
ABS actuator and electric unit
(control unit)Transmits the following signals via CAN communication to Transfer control unit.
lVehicle speed signal
lStop lamp switch signal (brake signal)
TF-84
TROUBLE DIAGNOSIS FOR SYSTEM
3.CHECK GROUND CIRCUIT
1. Turn ignition switch “OFF”. (Stay for at least 5 seconds.)
2. Disconnect ATP switch harness connector.
3. Check continuity between ATP switch harness connector F41
terminal 9 and ground.
Also check harness for short to power.
OK or NG
OK >> GO TO 4.
NG >> Repair open circuit or short to power in harness or con-
nectors.
4.CHECK ATP SWITCH
1. Turn ignition switch “OFF”. (Stay for at least 5 seconds.)
2. Remove ATP switch. Refer toTF-21, "
Location of Electrical Parts".
3. Push and release ATP switch and check continuity between ATP
switch terminals 8 and 9.
OK or NG
OK >> GO TO 5.
NG >> Replace ATP switch. Refer toTF-21, "
Location of Elec-
trical Parts".
5.CHECK TRANSFER CONTROL UNIT
Check transfer control unit input/output signal. Refer toTF-38, "
Transfer Control Unit Input/Output Signal Ref-
erence Values".
OK or NG
OK >> GO TO 6.
NG >> Check transfer control unit pin terminals for damage or loose connection with harness connector.
If any items are damaged, repair or replace damaged parts.
6.CHECK ATP WARNING LAMP
1. Turn ignition switch “ON”. (Do not start engine.)
2. Shift A/T selector lever to “N” position and engage the parking brake.
3. Switch 4WD shift switch from 4H to 4LO or 4LO to 4H.
Does ATP warning lamp turn
“ON”, while actuator motor is operating?
YES >>INSPECTION END
NO >> Go toTF-96, "
ATP Warning Lamp Does Not Turn ON". Continuity should exist.
SDIA2394E
Terminal Condition Continuity
8-9Push ATP switch Yes
Release ATP switch No
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