2005 INFINITI QX4 check engine
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TROUBLE DIAGNOSIS
TF-51
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Revision: October 20052005 QX56
Diagnostic Procedure
1. Warn 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 “LOCK”, “AUTO” and “LOCK” 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 conditionItems Malfunction Check items
2Output 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)"
3Clutch 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, "Tran s fe r Mo to r"
6Vehicle 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"
Page 3195 of 3419
TF-52
TROUBLE DIAGNOSIS
Revision: October 20052005 QX56
9Transfer fluid tempera-
ture
Signal voltage from fluid temperature sensor is abnor-
mally high (Transfer fluid temperature is abnormally low)
while driving.TF-102, "Transfer Fluid
Temperature"
10 Neutral-4LO switchImproper signal from neutral-4LO switch is input due to
open or short circuit.TF-59, "Neutral-4LO
Switch"
11 Clutch pressure switch
Improper signal from clutch pressure switch is input due
to open or short circuit.
Malfunction occurs in clutch pressure switch or hydraulic
circuit.TF-105, "
Clutch Pres-
sure Switch"
12 Line pressure switch
Improper signal from line pressure switch is input due to
open or short circuit.
Malfunction occurs in line pressure switch or hydraulic
circuit.TF-108, "
Line Pressure
Switch"
13Engine speed signal
(from ECM)
Malfunction is detected in engine speed signal that is
output from ECM through CAN communication.
Improper signal is input while driving.TF-85, "
Engine Speed
Signal (ECM)"
14Throttle position sen-
sor (from ECM)
Malfunction is detected in accelerator pedal position sig-
nal that is output from ECM through CAN communica-
tion.
Signal voltage from accelerator pedal position sensor is
abnormally high or low.T F - 111 , "
Throttle Posi-
tion Signal (ECM)"
15 Power supplyPower supply voltage for transfer control unit is abnor-
mally low while driving.TF-54, "Power Supply
Circuit For Transfer
Control Unit"
16 4WD shift switchMore than two switch inputs are simultaneously detected
due to short circuit of 4WD shift switch.TF-62, "4WD Shift
Switch"
17ABS operation signal
(from ABS)
Malfunction is detected in ABS operation signal that is
output from ABS actuator and electric unit (control unit)
through CAN communication.T F - 111 , "ABS Operation
Signal (ABS)"
18 Wait detection switchImproper signal from wait detection switch is input due to
open or short circuit.TF-66, "Wait Detection
Switch"
19 Actuator motor
Motor does not operate properly due to open or short cir-
cuit in actuator motor.
Malfunction is detected in the actuator motor. (When
4WD shift switch is operated and actuator motor is not
operated)
Malfunction is detected in transfer shift high relay and
transfer shift low relay.TF-70, "
Actuator
Motor", TF-54, "Power
Supply Circuit For
Transfer Control Unit"
20Actuator position
switch
Improper signal from actuator position switch is input
due to open or short circuit.
Malfunction is detected in the actuator position switch.TF-77, "
Actuator Posi-
tion Switch"
21 Actuator circuit
Transfer control device actuator circuit is shorted or
open. (Malfunctions are detected when motor relay cir-
cuit is open/shorted or relay transfer shift circuit is open/
shorted.)
Malfunction occurs in transfer control device drive circuit.TF-81, "
Transfer Con-
trol Device"
Malfunction is detected in transfer shut off relay.TF-54, "
Power Supply
Circuit For Transfer
Control Unit"
22VDC operation signal
(from VDC)
Malfunction is detected in VDC operation signal that is
output from ABS actuator and electric unit (control unit)
through CAN communication.TF-112, "VDC Opera-
tion Signal (ABS)"
23TCS operation signal
(from TCS)
Malfunction is detected in TCS operation signal that is
output from ABS actuator and electric unit (control unit)
through CAN communication.TF-112, "TCS Opera-
tion Signal (ABS)"
Flickering pattern or
flickering conditionItems Malfunction Check items
Page 3198 of 3419
TROUBLE DIAGNOSIS FOR SYSTEM
TF-55
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Revision: October 20052005 QX56
DIAGNOSTIC PROCEDURE
1. CHECK POWER SUPPLY
1. Turn ignition switch “OFF”. (Stay for at least 5 seconds.)
2. Connect transfer control unit harness connector.
3. Check voltage between transfer control unit harness connector
terminals and ground.
4. Turn ignition switch “ON”. (Do not start engine.)
5. Check voltage between transfer control unit harness connector
terminals and ground.
OK or NG
OK >> GO TO 2.
NG >> Check the following. If any items are damaged, repair or replace damaged parts.
10A fuses No. 26 located in fuse and fusible link box and No. 59 located in the fuse and relay
box. Refer to PG-4, "
POWER SUPPLY ROUTING CIRCUIT" .
20A fuse No. 53 located in the IPDM E/R. Refer to PG-4, "POWER SUPPLY ROUTING CIR-
CUIT" .
Harness for short or open between battery and transfer control unit harness connector termi-
nals 47.
Harness for short or open between battery and transfer control unit harness connector terminal
29.
Harness for short or open between battery and transfer shut off relay harness connector E69
terminal 1 (G), and 3 (G).
Harness for short or open between transfer shut off relay harness connector E69 terminal 2
(SB) and transfer control unit harness connector terminal 30.
Harness for short or open between transfer shut off relay harness connector E69 terminal 5 (Y/
R) and transfer control unit harness connector terminals 16 (Y/R) and 22 (Y/R).
Battery and ignition switch. Refer to PG-4, "POWER SUPPLY ROUTING CIRCUIT" .
Transfer shut off relay. Refer to TF-57, "COMPONENT INSPECTION" .
Connector Terminal (Wire color) Voltage (Approx.)
E14216 (Y/R) - Ground
0V 22 (Y/R) - Ground
E14329 (L/W) - Ground
30 (SB) - Ground
Battery voltage
47 (W) - Ground
WDIA0165E
Connector Terminal (Wire color) Voltage (Approx.)
E14216 (Y/R) - Ground
Battery voltage 22 (Y/R) - Ground
E14329 (L/W) - Ground
30 (SB) - Ground 0V
47 (W) - Ground Battery voltage
WDIA0166E
Page 3200 of 3419
TROUBLE DIAGNOSIS FOR SYSTEM
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Revision: October 20052005 QX56
COMPONENT INSPECTION
1. Turn ignition switch “OFF”. (Stay for at least 5 seconds.)
2. Remove transfer shut off relay. Refer to TF-22, "
Location of Electrical Parts" .
3. Apply 12V direct current between transfer shut off relay termi-
nals 1 and 2.
4. Check continuity between relay terminals 3 and 5.
5. If NG, replace the transfer shut off relay. Refer to TF-22, "
Loca-
tion of Electrical Parts" .
Transfer Control UnitEDS002I5
DIAGNOSTIC PROCEDURE
1. INSPECTION START
Do you have CONSULT-II?
YES or NO
YES >> GO TO 2.
NO >> GO TO 3.
2. PERFORM SELF-DIAGNOSIS (WITH CONSULT-II)
With CONSULT-II
1. Turn ignition switch “ON”. (Do not start engine.)
2. Select “SELF-DIAG RESULTS” mode for “ALL MODE AWD/4WD” with CONSULT-II.
3. Touch “ERASE”.
4. Turn ignition switch “OFF” and wait at least 10 seconds.
5. Perform the self-diagnosis again.
Is the
“CONTROL UNIT 1 [P1802]”, “CONTROL UNIT 2 [P1803]”, “CONTROL UNIT 3 [P1804]” or “CONTROL
UNIT 4 [P1809]” displayed?
YES >> Replace transfer control unit. Refer to TF-132, "Removal and Installation" .
NO >> Inspection End.
3. PERFORM SELF-DIAGNOSIS (WITHOUT CONSULT-II)
Without CONSULT-II
1. Perform the self-diagnosis and then erase self-diagnostic results. Refer to TF-50, "
SELF-DIAGNOSTIC
PROCEDURE (WITHOUT CONSULT-II)" and TF-53, "ERASE SELF-DIAGNOSIS" .
2. Perform the self-diagnosis again.
Do the self-diagnostic results indicate AD converter?
YES >> Replace transfer control unit. Refer to TF-132, "Removal and Installation" .
NO >> Inspection End.
Condition Continuity
12V direct current supply between terminals 1 and 2 Yes
OFF No
SCIA1245E
Page 3203 of 3419
TF-60
TROUBLE DIAGNOSIS FOR SYSTEM
Revision: October 20052005 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 (V) and neutral-4LO switch harness con-
nector F60 terminal 13 (V).
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 depressed4WD shift switch: 2WD,
AUTO or 4HOFF
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
ConnectorTe r m i n a l
(Wire
color)ConditionVoltage
(Approx.)
E143 25 (V) -
Ground
Vehicle stopped
Engine running
A/T selector lever
“N” position
Brake pedal
depressed4WD shift switch:
2WD, AUTO or 4HBattery
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
Page 3205 of 3419
TF-62
TROUBLE DIAGNOSIS FOR SYSTEM
Revision: October 20052005 QX56
COMPONENT INSPECTION
1. Turn ignition switch “OFF”. (Stay for at least 5 seconds.)
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.
5. If NG, replace the neutral-4LO switch. Refer to TF-22, "
Location
of Electrical Parts" .
4WD Shift SwitchEDS0 02 I9
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.Terminal Condition Continuity
12 - 13Push neutral-4LO switch Yes
Release neutral-4LO switch No
SDIA2696E
Monitored item [Unit] Content Condition Display value
2WD SWITCH [ON/
OFF]Input condition from 4WD
shift switch4WD shift switch: 2WD ON
4WD shift switch: AUTO, 4H or 4LO OFF
AUTO SWITCH [ON/
OFF]Input condition from 4WD
shift switch4WD shift switch: AUTO ON
4WD shift switch: 2WD, 4H or 4LO OFF
LOCK SWITCH [ON/
OFF]Input condition from 4WD
shift switch4WD shift switch: 4H ON
4WD shift switch: 2WD, AUTO or 4LO OFF
4L SWITCH [ON/OFF]Input condition from 4WD
shift switch4WD shift switch: 4LO ON
4WD shift switch: 2WD, AUTO or 4H OFF
4WD MODE [AUTO/
LOCK/2WD/4L]Control status of 4WD
(Output condition of 4WD
shift indicator lamp and
4LO indicator lamp)
Vehicle stopped
Engine running
A/T selector lever “N”
position
Brake pedal depressed4WD shift switch: 2WD 2WD
4WD shift switch: AUTO AUTO
4WD shift switch: 4H LOCK
4WD shift switch: 4LO 4L
Te r m i n a lWire
colorItem Condition Data (Approx.)
9G/W4WD shift switch
(2WD)Ignition switch: ON4WD shift switch: 2WD Battery voltage
4WD shift switch: AUTO, 4H or 4LO 0V
18 O4WD shift switch
(4H)Ignition switch: ON4WD shift switch: 4H Battery voltage
4WD shift switch: 2WD, AUTO or 4LO 0V
23 R4WD shift switch
(4LO)Ignition switch: ON4WD shift switch: 4LO Battery voltage
4WD shift switch: 2WD, AUTO or 4H 0V
24 LG/R4WD shift switch
(AUTO)Ignition switch: ON4WD shift switch: AUTO Battery voltage
4WD shift switch: 2WD, 4H or 4LO 0V
Page 3206 of 3419
TROUBLE DIAGNOSIS FOR SYSTEM
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Revision: October 20052005 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
ConnectorTe r m i n a l
(Wire color)ConditionVoltage
(Approx.)
E1429 (G/W) -
ground4WD shift switch: 2WD Battery voltage
4WD shift switch: AUTO, 4H or 4LO 0V
18 (O) -
ground4WD shift switch: 4H Battery voltage
4WD shift switch: 2WD, AUTO or
4LO 0V
23 (R) -
ground4WD shift switch: 4LO Battery voltage
4WD shift switch: 2WD, AUTO or
4H 0V
24 (LG/R) -
ground4WD shift switch: AUTO Battery voltage
4WD shift switch: 2WD, 4H or 4LO 0V
WDIA0148E
Page 3207 of 3419
TF-64
TROUBLE DIAGNOSIS FOR SYSTEM
Revision: October 20052005 QX56
2. CHECK 4WD SHIFT SWITCH POWER SUPPLY CIRCUIT
1. Turn ignition switch “OFF”. (Stay for at least 5 seconds.)
2. Disconnect 4WD shift switch harness connector.
3. Check voltage between 4WD shift switch harness connector ter-
minal 1 and ground.
4. Turn ignition switch “ON”. (Do not start engine.)
5. Check voltage between 4WD shift switch harness connector ter-
minal 1 and ground.
OK or NG
OK >> GO TO 3.
NG >> Go to TF-54, "
Power Supply Circuit For Transfer Control
Unit" .
3. CHECK HARNESS BETWEEN 4WD SHIFT SWITCH AND TRANSFER CONTROL UNIT
1. Turn ignition switch “OFF”. (Stay for at least 5 seconds.)
2. Disconnect transfer control unit harness connector and the 4WD shift switch harness connector.
3. Check continuity between the following terminals.
–Transfer control unit harness connector E142 terminal 9 (G/W)
and 4WD shift switch harness connector M141 terminal 2 (G/W).
–Transfer control unit harness connector E142 terminal 18 (O)
and 4WD shift switch harness connector M141 terminal 5 (O).
–Transfer control unit harness connector E142 terminal 23 (R)
and 4WD shift switch harness connector M141 terminal 6 (R).
–Transfer control unit harness connector E142 terminal 24 (LG/R)
and 4WD shift switch harness connector M141 terminal 3 (LG/
R).
Also check harness for short to ground and short to power.
OK or NG
OK >> GO TO 4.
NG >> Check the following. If any items are damaged, repair or replace damaged parts.
Harness for short or open between battery and transfer shut off relay harness connector E69
terminal 3 (G).
Power supply circuit for transfer control unit. Refer to PG-4, "POWER SUPPLY ROUTING CIR-
CUIT" .
Connector Terminal (Wire color) Voltage (Approx.)
M141 1 (W/R) - Ground 0V
SDIA2383E
Connector Terminal (Wire color) Voltage (Approx.)
M141 1 (W/R) - Ground Battery voltage
PDIA0210E
Continuity should exist.
SDIA2699E