TROUBLE DIAGNOSISTF-51
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Revision: November 2009 2006 QX56
Diagnostic Procedure
1. Warm up engine.
2. Move A/T selector lever to “P” position.
3. Turn 4WD shift switch to “2WD” position.
4. Turn ignition switch “ON” and “OFF ” at least twice, and then turn ignition switch “OFF”.
5. Turn 4WD shift switch to “AUTO” position.
6. Turn ignition switch “ON”. (Do not start engine.)
7. 4WD warning lamp ON. If 4WD warning lamp does not turn ON, refer to TF-121, "
4WD Warning Lamp Does Not Turn ON" .
8. Move A/T selector lever to “R” position.
9. Turn 4WD shift switch to “2WD”, “AUTO ” and “2WD ” in order.
10. Move A/T selector lever to “D” position.
11. Turn 4WD shift switch to “4H”, “AUTO ” and “4H” in order.
12. Move A/T selector lever to “N” position.
13. Turn 4WD shift switch to “AUTO” position.
14. Move A/T selector lever to “P” position.
15. Read the flickering of 4WD warning lamp. Refer to TF-51, "
Judgement Self-diagnosis" .
Judgement Self-diagnosis
When a malfunction is detected, the malfunction route is indicated by flickering of the 4WD warning lamp.
PDIA0227E
Flickering pattern or
flickering condition Items
Malfunction Check items
2 Output shaft revolution
signal (from TCM)
Malfunction is detected in output shaft revolution signal
that is output from TCM through CAN communication.
Improper signal is input while driving. TF-58, "
Output Shaft
Revolution Signal
(TCM)"
3
Clutch pressure sole-
noid signalProper voltage is not applied to clutch pressure solenoid
valve due to open or short circuit. TF-86, "Clutch Pres-
sure Solenoid"
4
2-4WD solenoid signalProper voltage is not applied to 2-4WD solenoid valve
due to open or short circuit. TF-91, "2-4WD Sole-
noid"
5
Transfer motorMotor does not operate properly due to open or short cir-
cuit in transfer motor or motor relay. TF-95, "Transfer Motor"
6
Vehicle speed signal
(from ABS)
Malfunction is detected in vehicle speed signal that is
output from ABS actuator and electric unit (control unit)
through CAN communication.
Improper signal is input while driving. TF-58, "
Vehicle Speed
Sensor (ABS)"
7
CAN communicationMalfunction has been detected from CAN communica-
tion line. TF-113, "CAN Commu-
nication Line"
8
AD converterAD converter system of transfer control unit is malfunc-
tioning. TF-54, "Power Supply
Circuit For Transfer
Control Unit"
TROUBLE DIAGNOSISTF-53
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CAUTION:
If “CAN communication” is displayed with other DTCs, first perform the trouble diagnosis for CAN communication line.
If “ABS operation signal”, “VDC operation signal" or “TCS operation signal" is displayed, first perform the trouble diag-
nosis for ABS system.
If “Output shaft revolution signal” is displayed, first perform the trouble diagnosis for A/T system.
NOTE:
If "actuator position switch" or “actuator circuit ” is displayed, first erase self-diagnostic results. ("Actuator position switch" or “actua-
tor circuit ” may be displayed after installing transfer control unit or transfer assembly.)
If “clutch pressure switch ” or “line pressure switch” is displayed only while driving in reverse, check the continuity of “R ” position on
A/T PNP switch. When there is nothing wrong with the electrical system, check the hydraulic system.
ERASE SELF-DIAGNOSIS
In order to make it easier to find the cause of hard-to-duplicate malfunctions, malfunction information is
stored into the control unit as necessary during use by the user. This memory is not erased no matter how
many times the ignition switch is turned ON and OFF.
However, this information is erased by turning ignition switch “OFF” after performing self-diagnostics or by
erasing the memory using the CONSULT-II.
24 PNP switch signal
(from TCM)When A/T PNP switch signal is malfunctioning or com-
munication error between the vehicles. TF-69, "PNP Switch
Signal (TCM)"
Repeats flickering
every 2 to 5 sec.
—
Circuits that the self-diagnosis covers have no malfunction. —
Repeats flickering
every 0.25 sec. Data erase display
Power supply failure of memory back-up.
Battery performance is poor. TF-54, "
Power Supply
Circuit For Transfer
Control Unit"
No flickering
PNP switch or 4WD
shift switchPNP switch or 4WD shift switch circuit is shorted or
open. TF-69, "PNP Switch
Signal (TCM)",
TF-62,
"4WD Shift Switch"
Flickering pattern or
flickering condition Items
Malfunction Check items
TF-56
TROUBLE DIAGNOSIS FOR SYSTEM
Revision: November 20092006 QX56
2. CHECK GROUND CIRCUIT
1. Turn ignition switch “ OFF”. (Stay for at least 5 seconds.)
2. Disconnect transfer control unit harness connector.
3. Check continuity between transfer control unit harness connec- tor E142 terminals 3, 6, E143 terminal 45 and ground.
Also check harness for short to ground and short to power.
OK or NG
OK >> GO TO 3.
NG >> Repair open circuit or short to ground or short to power in harness or connectors.
3. 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 4.
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.
4. 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" .
Continuity should exist.
SDIA2691E
TF-60
TROUBLE DIAGNOSIS FOR SYSTEM
Revision: November 20092006 QX56
DIAGNOSTIC PROCEDURE
1. CHECK 4LO POSITION SWITCH 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 “N POSI SW TF”.
Without CONSULT-II
1. Start engine.
2. Check voltage between transfer control unit harness connector terminal and ground.
OK or NG
OK >> GO TO 5.
NG >> GO TO 2.
2. CHECK HARNESS BETWEEN TRANSFER CONTROL UNIT AND NEUTRAL-4LO SWITCH
1. Turn ignition switch “ OFF”. (Stay for at least 5 seconds.)
2. Disconnect transfer control unit harness connector and the neutral-4LO switch harness connector.
3. Check continuity between transfer control unit harness connec- tor E143 terminal 25 and neutral-4LO switch harness connector
F60 terminal 13.
Also check harness for short to ground and short to power.
OK or NG
OK >> GO TO 3.
NG >> Repair or replace damaged parts.
Condition Display value
Vehicle stopped
Engine running
A/T selector lever “N ” position
Brake pedal depressed 4WD shift switch: 2WD,
AUTO or 4H
OFF
4WD shift switch: 4H to
4LO (While actuator
motor is operating.) OFF →
ON
4WD shift switch: 4LO to
4H (While actuator motor
is operating.) ON
→ OFF
4WD shift switch: 4LO ON
SDIA2692E
ConnectorTerminal
(Wire
color) Condition
Voltage
(Approx.)
E143 25 -
Ground
Vehicle stopped
Engine running
A/T selector lever
“ N ” position
Brake pedal
depressed 4WD shift switch:
2WD, AUTO or 4H
Battery
voltage
4WD shift switch: 4H
to 4LO (While actuator
motor is operating.) Battery
voltage
→
0V
4WD shift switch: 4LO
to 4H (While actuator
motor is operating.) 0V
→
Battery
voltage
4WD shift switch: 4LO 0V
SDIA2693E
Continuity should exist.
SDIA2694E
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3. CHECK GROUND CIRCUIT
1. Turn ignition switch “OFF”. (Stay for at least 5 seconds.)
2. Disconnect neutral-4LO switch harness connector.
3. Check continuity between neutral-4LO switch harness connec- tor F60 terminal 12 and ground.
Also check harness for short to ground and short to power.
OK or NG
OK >> GO TO 4.
NG >> Repair open circuit or short to ground or short to power in harness or connectors.
4. CHECK 4LO SWITCH
1. Turn ignition switch “OFF”.
2. Disconnect neutral-4LO switch harness connector.
3. Remove neutral-4LO switch. Refer to TF-22, "
Location of Electrical Parts" .
4. Push and release neutral-4LO switch and check continuity between neutral-4LO switch terminals 12 and 13.
OK or NG
OK >> GO TO 5.
NG >> Replace neutral-4LO switch. Refer to TF-22, "
Location
of Electrical Parts" .
5. CHECK TRANSFER CONTROL UNIT
Check transfer control unit input/output signal. Refer to TF-54, "
TRANSFER CONTROL UNIT TERMINALS
AND REFERENCE VALUE" .
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 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" .
Continuity should exist.
SDIA2695E
Terminal
Condition Continuity
12 - 13 Push neutral-4LO switch
Yes
Release neutral-4LO switch No
SDIA2696E
TROUBLE DIAGNOSIS FOR SYSTEMTF-63
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Revision: November 2009 2006 QX56
DIAGNOSTIC PROCEDURE
1. CHECK 4WD SHIFT SWITCH SIGNAL
With CONSULT-II
1. Turn ignition switch “ON”. (Do not start engine.)
2. Select “DATA MONITOR ” mode for “ALL MODE AWD/4WD ” with CONSULT-II.
3. Read out ON/OFF switching action of the “2WD SWITCH”,
“AUTO SWITCH”, “LOCK SWITCH”, “4L SWITCH ” with operat-
ing 4WD shift switch.
Without CONSULT-II
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 5.
NG >> GO TO 2.
SDIA2697E
Connector Terminal ConditionVoltage
(Approx.)
E142 9 - ground
4WD shift switch: 2WD
Battery voltage
4WD shift switch: AUTO, 4H or 4LO 0V
18 - ground 4WD shift switch: 4H
Battery voltage
4WD shift switch: 2WD, AUTO or
4LO 0V
23 - ground 4WD shift switch: 4LO
Battery voltage
4WD shift switch: 2WD, AUTO or
4H 0V
24 - ground 4WD shift switch: AUTO
Battery voltage
4WD shift switch: 2WD, 4H or 4LO 0V
WDIA0148E
TROUBLE DIAGNOSIS FOR SYSTEMTF-65
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4. CHECK 4WD SHIFT SWITCH
1. Turn ignition switch “OFF”. (Stay for at least 5 seconds.)
2. Disconnect 4WD shift switch harness connector.
3. Operate 4WD shift switch and check continuity between 4WD shift switch terminals.
OK or NG
OK >> GO TO 5.
NG >> Replace 4WD shift switch.
5. CHECK TRANSFER CONTROL UNIT
Check transfer control unit input/output signal. Refer to TF-54, "
TRANSFER CONTROL UNIT TERMINALS
AND REFERENCE VALUE" .
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 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" .
Connector TerminalConditionContinuity
M141 1 - 2
4WD shift switch: 2WD
Yes
4WD shift switch: AUTO, 4H and
4LO No
1 - 3 4WD shift switch: AUTO
Yes
4WD shift switch: 2WD, 4H and
4LO No
1 - 4 4WD shift switch: 2WD
No
4WD shift switch: AUTO, 4H and
4LO Ye s
1 - 5 4WD shift switch: 4H
Yes
4WD shift switch: 2WD, AUTO,
and 4LO No
1 - 6 4WD shift switch: 4LO
Yes
4WD shift switch: 2WD, AUTO
and 4H No
WDIA0205E
TROUBLE DIAGNOSIS FOR SYSTEMTF-67
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Revision: November 2009 2006 QX56
DIAGNOSTIC PROCEDURE
1. CHECK WAIT DETECTION SWITCH 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 “WAIT DETCT SW”.
Without CONSULT-II
1. Start engine.
2. Check voltage between transfer control unit harness connector terminal and ground.
OK or NG
OK >> GO TO 5.
NG >> GO TO 2.
2. CHECK HARNESS BETWEEN TRANSFER CONTROL UNIT AND WAIT DETECTION SWITCH
1. Turn ignition switch “OFF”. (Stay for at least 5 seconds.)
2. Disconnect transfer control unit harness connector and the wait detection switch harness connector.
3. Check continuity between transfer control unit harness connec- tor E143 terminal 43 and wait detection switch harness connec-
tor F59 terminal 10.
Also check harness for short to ground and short to power.
OK or NG
OK >> GO TO 3.
NG >> Repair or replace damaged parts.
Condition Display value
Vehicle stopped
Engine running
A/T selector lever “N” position
Brake pedal depressed 4WD shift switch: 2WD, AUTO
or 4H
OFF
4WD shift switch: 4H to 4LO
(While actuator motor is operat-
ing.) OFF
→ ON
4WD shift switch: 4LO to 4H
(While actuator motor is operat-
ing.) ON →
OFF
4WD shift switch: 4LO ON
PDIA0221E
Connector Terminal ConditionVoltage
(Approx.)
E143 43 -
Ground
Vehicle stopped
Engine running
A/T selector lever
“ N ” position
Brake pedal
depressed 4WD shift switch:
2WD, AUTO or 4H
Battery
voltage
4WD shift switch: 4H
to 4LO (While actua-
tor motor is operating.) Battery
voltage
→
0V
4WD shift switch: 4LO
to 4H (While actuator
motor is operating.) 0V
→
Battery
voltage
4WD shift switch: 4LO 0VSDIA2701E
Continuity should exist.
SDIA2702E