Page 3193 of 3383

TF-88
TROUBLE DIAGNOSIS FOR SYSTEM
Revision: November 20092006 QX56
2. CHECK HARNESS BETWEEN TRANSFER CONTROL UNIT AND CLUTCH PRESSURE SOLENOID
VA LV E
1. Turn ignition switch “OFF”. (Stay for at least 5 seconds.)
2. Disconnect transfer control unit harness connector, transfer terminal cord assembly harness connector and transfer dropping resistor.
3. Check continuity between transfer control unit harness connec- tor E142 terminal 19 and transfer terminal cord assembly har-
ness connector F56 terminal 6.
4. Check continuity between transfer dropping resistor harness connector E135 terminal 2 and transfer terminal cord assembly
harness connector F56 terminal 6.
Also check harness for short to ground and short to power.
OK or NG
OK >> GO TO 3.
NG >> Repair or replace damaged parts.
3. CHECK HARNESS BETWEEN TRANSFER CONTROL UNIT AND TRANSFER DROPPING RESISTOR
1. Turn ignition switch “ OFF”. (Stay for at least 5 seconds.)
2. Disconnect transfer control unit harness connector and transfer dropping resistor harness connector.
3. Check continuity between transfer control unit harness connec- tor E142 terminal 10 and transfer dropping resistor harness con-
nector E135 terminal 1.
Also check harness for short to ground and short to power.
OK or NG
OK >> GO TO 4.
NG >> Repair or replace damaged parts. Continuity should exist.
SDIA2720E
Continuity should exist.
SDIA2721E
Continuity should exist.
SDIA2722E
Page 3194 of 3383

TROUBLE DIAGNOSIS FOR SYSTEMTF-89
CE F
G H
I
J
K L
M A
B
TF
Revision: November 2009 2006 QX56
4. CHECK GROUND CIRCUIT
1. Turn ignition switch “OFF”. (Stay for at least 5 seconds.)
2. Disconnect transfer terminal cord assembly harness connector.
3. Check continuity between transfer terminal cord assembly har- ness connector F56 terminal 19 and ground.
Also check harness for short to ground and short to power.
OK or NG
OK >> GO TO 5.
NG >> Repair open circuit or short to ground or short to power in harness or connectors.
5. CHECK CLUTCH PRESSURE SOLENOID
1. Turn ignition switch “OFF”. (Stay for at least 5 seconds.)
2. Disconnect transfer terminal cord assembly harness connector.
3. Check resistance between transfer terminal cord assembly ter- minals 6 and 19.
OK or NG
OK >> GO TO 6.
NG >> Replace clutch pressure solenoid. Refer to TF-22,
"Location of Electrical Parts" .
6. CHECK TRANSFER DROPPING RESISTOR
1. Turn ignition switch “OFF”. (Stay for at least 5 seconds.)
2. Disconnect transfer dropping resistor harness connector. Refer to TF-22, "
Location of Electrical Parts" .
3. Check resistance between transfer dropping resistor terminals 1 and 2.
OK or NG
OK >> GO TO 7.
NG >> Replace transfer dropping resistor. Refer to TF-22,
"Location of Electrical Parts" .
7. CHECK TRANSFER CONTROL UNIT
Check transfer control unit input/output signal. Refer to TF-35, "
Transfer Control Unit Input/Output Signal Ref-
erence Values" .
OK or NG
OK >> GO TO 8.
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.
Continuity should exist.
SDIA2723E
6 - 19 : Approx. 3.0 - 3.4
\b
WDIA0225E
1 - 2 : Approx. 11.2 - 12.8 \b
SDIA2725E
Page 3195 of 3383

TF-90
TROUBLE DIAGNOSIS FOR SYSTEM
Revision: November 20092006 QX56
8. CHECK DTC
Perform the self-diagnosis, after driving a vehicle for a while.
OK or NG
OK >> Inspection End.
NG >> Replace transfer control unit. Refer to TF-132, "
Removal and Installation" .
COMPONENT INSPECTION
Clutch Pressure Solenoid
1. Turn ignition switch “ OFF”. (Stay for at least 5 seconds.)
2. Disconnect transfer terminal cord assembly harness connector.
3. Check resistance between transfer terminal cord assembly ter- minals 6 and 19.
4. If NG, replace clutch pressure solenoid. Refer to TF-22, "
Loca-
tion of Electrical Parts" .
Transfer Dropping Resistor
1. Turn ignition switch “ OFF”. (Stay for at least 5 seconds.)
2. Disconnect transfer dropping resistor harness connector.
3. Check resistance between transfer dropping resistor terminals 1 and 2.
4. If NG, replace transfer dropping resistor. Refer to TF-22, "
Loca-
tion of Electrical Parts" .
6 - 19 : Approx. 3.0 - 3.4
\b
WDIA0225E
1 - 2 : Approx. 11.2 - 12.8 \b
SDIA2725E
Page 3196 of 3383

TROUBLE DIAGNOSIS FOR SYSTEMTF-91
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M A
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TF
Revision: November 2009 2006 QX56
2-4WD SolenoidEDS002IH
CONSULT-II REFERENCE VALUE IN DATA MONITOR MODE
Data are reference value.
TRANSFER CONTROL UNIT TERMINALS AND REFERENCE VALUE
Data are reference value and are measured between each terminal and ground.
CAUTION:
When using a circuit tester to measure voltage for inspection, be sure not to extend forcibly any connector terminals.
DIAGNOSTIC PROCEDURE
1. CHECK 4WD SHIFT SWITCH SYSTEM
Perform self-diagnosis. Refer to TF-50, "
Self-diagnostic Procedure" .
Is the "4WD MOD SW [P1814]" (with CONSULT-II) or "Flickering pattern: 16 (without CONSULT-II) detected?
YES >> Perform trouble diagnosis for 4WD shift switch. Refer to TF-62, "4WD Shift Switch" .
NO >> GO TO 2.
Monitored item Content ConditionDisplay value
2-4WD SOL [ON/OFF] Condition of 2-4WD shift
solenoid valve
Vehicle stopped
Engine running
A/T selector lever “
N”
position
Brake pedal depressed 4WD shift switch: 2WD
OFF
4WD shift switch: AUTO ON
4WD shift switch: 4H
4WD shift switch: 4LO
4WD shift switch: AUTO
( “ Wait ” function is operat-
ing.) OFF
4WD shift switch: 4H
( “ Wait ” function is operat-
ing.) OFF
2-4WD SOL MON [ON/
OFF] Check signal for transfer
control unit signal output
Vehicle stopped
Engine running
A/T selector lever “
N”
position
Brake pedal depressed 4WD shift switch: 2WD
OFF
4WD shift switch: AUTO ON
4WD shift switch: 4H
4WD shift switch: 4LO
4WD shift switch: AUTO
( “ Wait ” function is operat-
ing.) OFF
4WD shift switch: 4H
( “ Wait ” function is operat-
ing.) OFF
Terminal
Wire
color Item
ConditionData (Approx.)
1 GR 2-4WD shift solenoid valve
Vehicle stopped
Engine running
A/T selector
lever “N ” position
Brake pedal
depressed 4WD shift switch: 2WD 0V
4WD shift switch: AUTO, 4H or 4LO Battery voltage
Page 3197 of 3383

TF-92
TROUBLE DIAGNOSIS FOR SYSTEM
Revision: November 20092006 QX56
2. CHECK 2-4WD SHIFT SOLENOID SIGNAL
With CONSULT-II
1. Start engine.
2. Select “DATA MONITOR ” mode for “ALL MODE AWD/4WD ” with CONSULT-II.
3. Read out the value of “2-4WD SOL” and “2-4WD SOL MON ”.
Without CONSULT-II
1. Start engine.
2. Check voltage between transfer control unit harness connector terminal and ground.
OK or NG
OK >> GO TO 7.
NG >> GO TO 3.
Monitored item Condition Display
value
2-4WD SOL
Vehicle stopped
Engine running
A/T selector lever “N ”
position
Brake pedal
depressed 4WD shift switch: 2WD OFF
4WD shift switch: AUTO
ON
4WD shift switch: 4H
4WD shift switch: 4LO
4WD shift switch: AUTO
( “Wait ” function is operat-
ing.) OFF
4WD shift switch: 4H ( “Wait ”
function is operating.) OFF
2-4WD SOL
MON
Vehicle stopped
Engine running
A/T selector lever “N ”
position
Brake pedal
depressed 4WD shift switch: 2WD OFF
4WD shift switch: AUTO
ON
4WD shift switch: 4H
4WD shift switch: 4LO
4WD shift switch: AUTO
( “Wait ” function is operat-
ing.) OFF
4WD shift switch: 4H ( “Wait ”
function is operating.) OFF
SDIA2727E
Connector Terminal
ConditionVoltage
(Approx.)
E142 1 -
Ground
Vehicle stopped
Engine running
A/T selector lever
“ N ” position
Brake pedal
depressed 4WD shift switch:
2WD
0V
4WD shift switch:
AUTO, 4H or 4LO Battery
voltage
SDIA2728E
Page 3198 of 3383

TROUBLE DIAGNOSIS FOR SYSTEMTF-93
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M A
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TF
Revision: November 2009 2006 QX56
3. CHECK 4WD SHIFT SWITCH SIGNAL
1. Turn ignition switch “ON”. (Do not start engine.)
2. Check voltage between transfer control unit harness connector terminals and ground.
OK or NG
OK >> GO TO 4.
NG >> Check 4WD shift switch. Refer to TF-66, "
COMPONENT INSPECTION" .
4. CHECK HARNESS BETWEEN 4WD SHIFT SWITCH AND TRANSFER TERMINAL CORD ASSEMBLY
1. Turn ignition switch “OFF”. (Stay for at least 5 seconds.)
2. Disconnect 4WD shift switch harness connector and transfer terminal cord assembly harness connector.
3. Check continuity between 4WD shift switch harness connector M141 terminal 4 and transfer terminal cord assembly harness
connector F56 terminal 5.
Also check harness for short to ground and short to power.
OK or NG
OK >> GO TO 5.
NG >> Repair or replace damaged parts.
5. CHECK HARNESS BETWEEN TRANSFER CONTROL UNIT AND TRANSFER TERMINAL CORD
ASSEMBLY
1. Turn ignition switch “OFF”. (Stay for at least 5 seconds.)
2. Disconnect transfer control unit harness connector and transfer terminal cord assembly harness connec- tor.
3. Check continuity between transfer control unit harness connec- tor E142 terminal 1 and transfer terminal cord assembly harness
connector F56 terminal 4.
Also check harness for short to ground and short to power.
OK or NG
OK >> GO TO 6.
NG >> Repair or replace damaged parts.
Connector Terminal ConditionVoltage
(Approx.)
M141 4 - ground 4WD shift switch: AUTO, 4H or 4LO Battery voltage
4WD shift switch: 2WD
0V
SDIA2729E
Continuity should exist.
SDIA2731E
Continuity should exist.
SDIA2732E
Page 3199 of 3383

TF-94
TROUBLE DIAGNOSIS FOR SYSTEM
Revision: November 20092006 QX56
6. CHECK 2-4WD SOLENOID
1. Turn ignition switch “ OFF”. (Stay for at least 5 seconds.)
2. Disconnect transfer terminal cord assembly harness connector.
3. Check resistance between transfer terminal cord assembly ter- minals 4 and 5.
OK or NG
OK >> GO TO 7.
NG >> 2-4WD solenoid is malfunctioning. Refer to TF-22,
"Location of Electrical Parts" .
7. CHECK TRANSFER CONTROL UNIT
Check transfer control unit input/output signal. Refer to TF-35, "
Transfer Control Unit Input/Output Signal Ref-
erence Values" .
OK or NG
OK >> GO TO 8.
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.
8. CHECK DTC
Perform the self-diagnosis, after driving a vehicle for a while.
OK or NG
OK >> Inspection End.
NG >> Replace transfer control unit. Refer to TF-132, "
Removal and Installation" .
COMPONENT INSPECTION
1. Turn ignition switch “OFF ”. (Stay for at least 5 seconds.)
2. Disconnect transfer terminal cord assembly harness connector.
3. Check resistance between transfer terminal cord assembly ter- minals 4 and 5.
4. If NG, replace the 2-4WD solenoid. Refer to TF-22, "
Location of
Electrical Parts" .
4 - 5 : Approx. 22.8 - 25.2
\b
WDIA0187E
4 - 5 : Approx. 22.8 - 25.2 \b
WDIA0187E
Page 3200 of 3383

TROUBLE DIAGNOSIS FOR SYSTEMTF-95
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M A
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TF
Revision: November 2009 2006 QX56
Transfer MotorEDS002II
CONSULT-II REFERENCE VALUE IN DATA MONITOR MODE
Data are reference value.
Monitored item Content ConditionDisplay value
MOTOR RELAY [ON/
OFF] Condition of transfer motor
relay
Accelerator pedal
depressed
Vehicle stopped
Engine running
Brake pedal depressed4WD shift switch: 2WD
OFF
4WD shift switch: AUTO
or 4LO (A/T selector lever
“ P ” or “N ” position) OFF
("ON" for approx. 2
sec. after shifting to “P ” and “ N”.)
4WD shift switch: AUTO
or 4LO (Except for A/T
selector lever “P ” or “ N”
position) ON
4WD shift switch: 4H (A/T
selector lever “P ” posi-
tion) OFF
("ON" for approx. 2
sec. after shifting to “P ”.)
4WD shift switch: 4H
(Except for A/T selector
lever “P ” position) ON
MOTOR RELAY MON
[ON/OFF] Check signal for transfer
control unit signal output
Accelerator pedal
depressed
Vehicle stopped
Engine running
Brake pedal depressed4WD shift switch: 2WD
OFF
4WD shift switch: AUTO
or 4LO (A/T selector lever
“ P ” or “N ” position) OFF
("ON" for approx. 2
sec. after shifting to “P ” and “ N”.)
4WD shift switch: AUTO
or 4LO (Except for A/T
selector lever “P ” or “ N”
position) ON
4WD shift switch: 4H (A/T
selector lever “P ” posi-
tion) OFF
("ON" for approx. 2
sec. after shifting to “P ”.)
4WD shift switch: 4H
(Except for A/T selector
lever “P ” position) ON