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SRS-8
TROUBLE DIAGNOSIS
Revision: October 20052005 QX56
TROUBLE DIAGNOSISPFP:00004
Trouble Diagnosis IntroductionEHS0016M
CAUTION:
Do not use electrical test equipment on any circuit related to the SRS unless instructed to do so in
this Service Manual. SRS wiring harnesses can be identified by yellow and/or orange harness con-
nectors.
Do not attempt to repair, splice or modify SRS wiring harnesses. If a harness is damaged, replace
it with a new one.
Keep ground connections clean.
DIAGNOSIS FUNCTION
The SRS self-diagnosis results can be read by using “AIR BAG” warning lamp and/or CONSULT-II.
The User mode is exclusively prepared for the customer (driver). This mode warns the driver of a system mal-
function through the operation of the “AIR BAG” warning lamp.
The Diagnosis mode allows the technician to locate and inspect the malfunctioning part.
The mode applications for the “AIR BAG” warning lamp and CONSULT-II are as follows:
HOW TO PERFORM TROUBLE DIAGNOSES FOR QUICK AND ACCURATE REPAIR
A good understanding of the malfunction conditions can make troubleshooting faster and more accurate.
In general, each customer feels differently about a malfunction. It is important to fully understand the symp-
toms or conditions for a customer complaint.
Information From Customer
WHAT - Vehicle model
WHEN - Date, Frequencies
WHERE - Road conditions
HOW - Operating conditions, Symptoms
Preliminary Check
Check that the following parts are in good order.
Battery (Refer to SC-4, "How to Handle Battery" .)
Fuse (Refer to SRS-12, "Wiring Diagram— SRS —" .)
System component-to-harness connections
User mode Diagnosis mode Display type
“AIR BAG” warning lamp X X ON-OFF operation
CONSULT-II — X Monitoring
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SRS-12
TROUBLE DIAGNOSIS
Revision: October 20052005 QX56
Wiring Diagram— SRS —EHS0016P
WHWA0117E
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TF-1
TRANSFER
D DRIVELINE/AXLE
CONTENTS
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SECTION TF
A
B
TF
Revision: October 20052005 QX56 PRECAUTIONS .......................................................... 4
Precautions for Supplemental Restraint System
(SRS) “AIR BAG” and “SEAT BELT PRE-TEN-
SIONER” .................................................................. 4
Precautions for Transfer Assembly and Transfer
Control Unit Replacement ........................................ 4
METHOD FOR POSITION ADJUSTMENT ........... 4
Precautions .............................................................. 4
Service Notice .......................................................... 5
Wiring Diagrams and Trouble Diagnosis .................. 5
PREPARATION ........................................................... 6
Special Service Tools ............................................... 6
Commercial Service Tools ........................................ 9
NOISE, VIBRATION AND HARSHNESS (NVH)
TROUBLESHOOTING .............................................. 10
NVH Troubleshooting Chart ................................... 10
TRANSFER FLUID ....................................................11
Replacement ...........................................................11
DRAINING ............................................................11
FILLING ................................................................11
Inspection ................................................................11
FLUID LEAKAGE AND FLUID LEVEL .................11
ALL-MODE 4WD SYSTEM ...................................... 12
Cross-section View ................................................ 12
Power Transfer ....................................................... 13
POWER TRANSFER DIAGRAM ........................ 13
POWER TRANSFER FLOW ............................... 14
System Description ................................................ 15
CONTROL SYSTEM ........................................... 15
TRANSFER MOTOR .......................................... 16
WAIT DETECTION SWITCH .............................. 17
NEUTRAL-4LO SWITCH .................................... 17
ATP SWITCH ...................................................... 17
2-4WD SHIFT SOLENOID VALVE ...................... 17
CLUTCH PRESSURE SOLENOID VALVE ......... 17
LINE PRESSURE SWITCH ................................ 18
CLUTCH PRESSURE SWITCH .......................... 18
TRANSFER FLUID TEMPERATURE SENSOR ... 18
TRANSFER CONTROL UNIT ............................. 18
TRANSFER CONTROL DEVICE ........................ 184WD SHIFT SWITCH AND INDICATOR LAMP ... 18
4WD WARNING LAMP ....................................... 19
ATP WARNING LAMP ......................................... 19
System Diagram ..................................................... 19
COMPONENTS FUNCTION ............................... 20
CAN Communication .............................................. 20
SYSTEM DESCRIPTION .................................... 20
TROUBLE DIAGNOSIS ............................................ 21
How to Perform Trouble Diagnosis ......................... 21
BASIC CONCEPT ............................................... 21
Location of Electrical Parts ..................................... 22
Circuit Diagram ....................................................... 23
Wiring Diagram — T/F — ....................................... 24
Inspections Before Trouble Diagnosis .................... 32
TRANSFER FLUID CHECK ................................ 32
PREPARATION FOR ROAD TEST ..................... 32
CHECK BEFORE ENGINE IS STARTED ........... 32
CHECK AT IDLE .................................................. 32
CRUISE TEST ..................................................... 34
Trouble Diagnosis Chart for Symptoms .................. 34
Transfer Control Unit Input/Output Signal Refer-
ence Values ............................................................ 36
TRANSFER CONTROL UNIT INSPECTION
TABLE ................................................................. 36
CONSULT-II Function (ALL MODE AWD/4WD) ..... 44
FUNCTION .......................................................... 44
CONSULT-II SETTING PROCEDURE ................ 44
SELF-DIAG RESULT MODE ............................... 45
DATA MONITOR MODE ...................................... 47
WORK SUPPORT ............................................... 49
Self-diagnostic Procedure ...................................... 50
SELF-DIAGNOSTIC PROCEDURE (WITH
CONSULT-II) ....................................................... 50
SELF-DIAGNOSTIC PROCEDURE (WITHOUT
CONSULT-II) ....................................................... 50
ERASE SELF-DIAGNOSIS ................................. 53
TROUBLE DIAGNOSIS FOR SYSTEM .................... 54
Power Supply Circuit For Transfer Control Unit ...... 54
CONSULT-II REFERENCE VALUE IN DATA
MONITOR MODE ................................................ 54
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PRECAUTIONS
TF-5
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TF
Revision: October 20052005 QX56
When connecting or disconnecting pin connectors into or
from transfer control unit, take care not to damage pin ter-
minals (bend or break).
When connecting pin connectors make sure that there are
not any bends or breaks on transfer control unit pin termi-
nals.
Before replacing transfer control unit, perform transfer con-
trol unit input/output signal inspection and make sure
transfer control unit functions properly. Refer to TF-36,
"Transfer Control Unit Input/Output Signal Reference Val-
ues" .
Service NoticeEDS0 02 H6
After overhaul refill the transfer with new transfer fluid.
Check the fluid level or replace the fluid only with the vehicle parked on level ground.
During removal or installation, keep inside of transfer clear of dust or dirt.
Disassembly should be done in a clean work area.
Before proceeding with disassembly, thoroughly clean the transfer. It is important to prevent the internal
parts from becoming contaminated by dirt or other foreign matter.
Check for the correct installation status prior to removal or disassembly. If matchmarks are required, be
certain they do not interfere with the function of the parts when applied.
All parts should be carefully cleaned with a general purpose, non-flammable solvent before inspection or
reassembly.
Check appearance of the disassembled parts for damage, deformation, and unusual wear. Replace them
with new ones if necessary.
Gaskets, seals and O-rings should replaced any time the transfer is disassembled.
In principle, tighten bolts or nuts gradually in several steps working diagonally from inside to outside. If
tightening sequence is specified, use it.
Observe the specified torque when assembling.
Clean and flush the parts sufficiently and blow-dry them.
Be careful not to damage sliding surfaces and mating surfaces.
Use lint-free cloth or towels for wiping parts clean. Common shop rags can leave fibers that could interfere
with the operation of the transfer.
Wiring Diagrams and Trouble DiagnosisEDS0 02 H7
When reading wiring diagrams, refer to the following:
GI-15, "How to Read Wiring Diagrams".
PG-4, "POWER SUPPLY ROUTING CIRCUIT".
When performing trouble diagnosis, refer to the following:
GI-11, "How to Follow Trouble Diagnoses".
GI-27, "How to Perform Efficient Diagnosis for an Electrical Incident".
SEF 2 91 H
MEF040DB
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ALL-MODE 4WD SYSTEM
TF-13
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Revision: October 20052005 QX56
Power TransferEDS0 02 H9
POWER TRANSFER DIAGRAM
1. Center case 2. Chain 3. Multiple disc clutch
4. Rear case 5. Mainshaft 6. Clutch hub assembly
7. Sub oil pump 8. Transfer motor 9. Control valve
10. Front drive shaft 11. Drain plug 12. 2-4 sleeve
13. Sun gear assembly 14. L-H sleeve 15. Planetary carrier assembly
16. Internal gear 17. Front case
LDIA0053E
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ALL-MODE 4WD SYSTEM
TF-19
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Revision: October 20052005 QX56
4WD WARNING LAMP
Turns ON or FLASH when there is a malfunction in 4WD system.
Also turns ON when ignition switch is turned ON, for purpose of lamp check. Turns OFF for approximately 1
second after the engine starts if system is normal.
4WD Warning Lamp Indication
*: When 4WD warning lamp is ON, all the 4WD shift indicator lamps turn OFF.
AT P WA R N I N G L A M P
Even if A/T selector lever is in “P” position, vehicle may move because A/T parking mechanism does not oper-
ate when transfer is under neutral condition. ATP warning lamp is turned on so as to indicate this condition to
the driver.
System DiagramEDS002HB
Condition Content 4WD warning lamp
During self-diagnosis Indicates the malfunction position by number of flickers. Flickers at malfunction mode.
Lamp check*Checks the lamp by turning ON during engine starting. After
engine starts, it turns OFF if there are no malfunctions.ON
Malfunction in 4WD system*Turns ON to indicate malfunction. When ignition switch is
turned to “OFF” or the malfunction is corrected, it turns OFF.ON
When vehicle is driven with different
diameters of front and rear tiresFlickers once every 2 seconds.
Turns OFF when ignition switch is “OFF”.Flickers once every 2 sec-
onds.
High fluid temperature in transfer unitWhen fluid temperature is high or fluid temperature sensor cir-
cuit is shorted, it flickers twice every second.
It turns OFF when fluid temperature becomes normal.Flickers twice a second.
Other than above (System is nor-
mal.)Lamp is OFF. OFF
WDIA0164E
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TROUBLE DIAGNOSIS
TF-23
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Revision: October 20052005 QX56
Circuit DiagramEDS002HF
WDWA0015E
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TF-24
TROUBLE DIAGNOSIS
Revision: October 20052005 QX56
Wiring Diagram — T/F —EDS002HG
WDWA0016E