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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)
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4WD SYSTEM
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CAN CommunicationEDS0031N
SYSTEM DESCRIPTION
CAN (Controller Area Network) is a serial communication line for real time application. It is an on-vehicle mul-
tiplex communication line with high data communication speed and excellent error detection ability. Many elec-
tronic control units are equipped onto a vehicle, and each control unit shares information and links with other
control units during operation (not independent). In CAN communication, control units are connected with 2
communication lines (CAN H line, CAN L line) allowing a high rate of information transmission with less wiring.
Each control unit transmits/receives data but selectively reads required data only.
For details, refer toLAN-23, "
CAN COMMUNICATION".
TCM
(A/T models)Transmits the following signal via CAN communication to Transfer control unit.lOutput shaft revolution signal
lA/T position indicator signal (PNP switch signal)
ECMTransmits engine speed signal via CAN communication to Transfer control unit.
lEngine speed signal Component parts Function
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TF-20
TROUBLE DIAGNOSIS
TROUBLE DIAGNOSIS
PFP:00004
How to Perform Trouble DiagnosisEDS0031O
BASIC CONCEPT
lTo perform trouble diagnosis, it is important to have understanding about vehicle systems (control and
mechanism).
lIt is also important to clarify customer complaints before inspec-
tion.
First of all, reproduce symptoms, and understand them fully.
Ask customer about his/her complaints carefully. In some cases,
it will be necessary to check symptoms by driving vehicle with
customer.
CAUTION:
Customers are not professional. It is dangerous to make an
easy guess like "maybe the customer means that...," or
"maybe the customer mentions this symptom".
lIt is essential to check symptoms right from the beginning in
order to repair malfunctions completely.
For intermittent malfunctions, reproduce symptoms based on
interview with customer and past examples. Do not perform
inspection on ad hoc basis. Most intermittent malfunctions are
caused by poor contacts. In this case, it will be effective to shake
suspected harness or connector by hand. When repairing with-
out any symptom diagnosis, you cannot judge if malfunctions
have actually been eliminated.
lAfter completing diagnosis, always erase diagnostic memory.
Refer toTF-51, "
ERASE SELF-DIAGNOSIS".
lFor intermittent malfunctions, move harness or harness connec-
tor by hand. Then check for poor contact or reproduced open circuit.
SEF233G
SEF234G
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TROUBLE DIAGNOSIS
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Location of Electrical PartsEDS0031P
A/T MODELS
SDIA3414E
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TF-22
TROUBLE DIAGNOSIS
M/T MODELS
SDIA3415E
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TROUBLE DIAGNOSIS
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Circuit DiagramEDS0031Q
A/T MODELS
MDWA0069E
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TF-24
TROUBLE DIAGNOSIS
M/T MODELS
MDWA0070E
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TROUBLE DIAGNOSIS
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Wiring Diagram — T/F —EDS0031R
A/T MODELS
MDWA0047E