2004 INFINITI QX56 warning

TF-28
ON BOARD DIAGNOSTIC SYSTEM DESCRIPTION
Revision: August 20072004 QX56
SELF-DIAGNOSTIC PROCEDURE
INDICATIONS OF 4WD WARNING LAMP
*1:TF-87*2:TF-28
WDIA0070E

ON BOARD DIAGNOSTIC SYSTEM DESCRIPTION
TF-33
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Revision: August 20072004 QX56
Note 1: When a malfunction occurs, it is only displayed and not stored in the memory.
Note 2: When the wait detection switch has been properly fixed, malfunction information is erased from the memory.
Note 3: If 4WD shift switch is left between 4H and 4LO for a while, this indication may be displayed.
(*1): If the malfunction is detected 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.
(*2): If a revolution sensor malfunction is detected at the same time, check the revolution sensor circuit first.
Note 4: When this malfunction is detected with the ABS warning lamp off, first check for disconnection or shorting in the harness
between the transfer control unit and the ABS control unit.
Note 5: When several systems including CAN communication system indicate malfunctions, perform diagnosis of the CAN communica-
tion first.Shift actuator abnormal
(SHIFT ACT)Transfer control device actuator motor is malfunctioning.
(Malfunctions are detected when actuator motor fails to
operate while shifting from “4H” to “4LO” or vice versa.) Refer to TF-77, "
Diagnostic Proce-
dure" or TF-82, "Diagnostic Pro-
cedure" .
Shift actuator position switch
abnormal
(SHIFT ACT P/S)Transfer control device actuator motor arm position sens-
ing switch is malfunctioning.Refer to TF-80, "
Diagnostic Proce-
dure" or TF-82, "Diagnostic Pro-
cedure" .
Shift actuator circuit abnormal
(SHIFT ACT CIR)Transfer control device actuator circuit is shorted or open.
(Malfunctions are detected when motor relay circuit is
open/shorted or relay monitor circuit is open/shorted.)Refer to TF-77, "
Diagnostic Proce-
dure" , TF-80, "Diagnostic Proce-
dure"TF-82, "Diagnostic
Procedure" .
Memory power supply stop

Due to removal of battery which cuts off power supply to
transfer control unit, self-diagnosis memory function is
suspended.Refer to TF-76, "Diagnostic Proce-
dure" .
Transfer control unit (RAM)
[CONTROL UNIT (RAM)]

Malfunction is detected in the memory (RAM) system of
transfer control unit.—
Transfer control unit (ROM)
[CONTROL UNIT (ROM)]

Malfunction is detected in the memory (ROM) system of
transfer control unit.—
Transfer control unit (EEPROM)
[CONTROL UNIT (EEPROM)]

Malfunction is detected in the memory (EEPROM) sys-
tem of transfer control unit.—
Longitudinal G-sensor Displayed, but do not use. —
ABS VHL SPD SEN

ABS vehicle speed sensor signal is not input due to an
open circuit.

An unexpected signal is input when vehicle is being
driven.Refer to ABS vehicle speed sensor
diagnosis.
STEERING ANGLE SENSOR Displayed, but do not use. —
VDC OPER SIGIf VDC operation signal is being input because of VDC
malfunction or communication error within the vehicle.Refer to BRC-40, "
ABS/TCS/VDC
Control Unit Inspection" .
TCS OPER SIGIf TCS operation signal is being input because of TCS mal-
function or communication error within the vehicle.Refer to BRC-40, "
ABS/TCS/VDC
Control Unit Inspection" .
CAN COMM (Note 5) Malfunction is detected in CAN communication.Refer to LAN-5, "
CAN COMMUNI-
CATION" .
A/T POSITION SIGNALWhen AT PNP switch circuit is malfunction or communica-
tion error between the vehiclesRefer to AT-109, "
DTC P0705
PARK/NEUTRAL POSITION
SWITCH" . Detected items
(Screen terms for CONSULT-II,
“SELF-DIAG RESULT” mode)Malfunction is detected when... Check items

TF-36
ON BOARD DIAGNOSTIC SYSTEM DESCRIPTION
Revision: August 20072004 QX56
N position switch TF [ON-OFF] N position switch of transfer
Line pressure switch [ON-OFF] Line pressure switch
Clutch pressure switch [ON-OFF] Clutch pressure switch
ATP switch [ON-OFF]—
N position switch AT [ON-OFF] “N” position on A/T PNP switch
R position switch AT [ON-OFF] “R” position on A/T PNP switch
P position switch AT [ON-OFF] “P” position on A/T PNP switch
ABS operation switch [ON-OFF] ABS operation switch
Wait detection switch [ON-OFF] —
Throttle positionThrottle opening recognized by transfer
control unit
4WD-mode4WD-mode recognized by transfer control
unit (2WD, AUTO, 4H & 4LO)
Vehicle speed comp [km/h (MPH)]Vehicle speed recognized by transfer con-
trol unit
*Control torque [N·m (kg-m, ft.-lb.)]Calculated torque recognized by transfer
control unit
Duty solenoid valve [%]
(Transfer 4WD solenoid valve)—
2-4WD shift solenoid valve [ON-
OFF]
Control signal outputs of transfer control
unit Transfer motor relay [ON-OFF]
Shift activating 1 [ON-OFF]
Shift activating 2 [ON-OFF]
2-4WD shift solenoid valve monitor
[ON-OFF]
Check signal (re-input signal) of transfer
control unit control signal output is dis-
played. If circuit is shorted or open, ON/OFF
state does not change. Transfer motor relay monitor [ON-
OFF]
Shift activating monitor 1 [ON-OFF]
Shift activating monitor 2 [ON-OFF]
4WD fail lamp [ON-OFF]Transfer control unit control signal output for
4WD warning lamp (left)
Shift position switch 1 [ON-OFF] —
Shift position switch 2 [ON-OFF] —
2WD indicator lamp [ON-OFF]Transfer control unit control signal output for
4WD shift indicator lamp (rear)
AUTO indicator lamp [ON-OFF]Transfer control unit control signal output for
4WD shift indicator lamp (front & rear)
LOCK indicator lamp [ON-OFF]Transfer control unit control signal output for
4WD shift indicator lamp (center)
4LO indicator lamp [ON-OFF]Transfer control unit control signal output for
4WD shift indicator lamp (right) Item [Unit]Monitor item
Remarks ECU
INPUT
SIGNALSMAIN
SIGNALSSELEC-
TION
FROM
MENU

TF-44
TROUBLE DIAGNOSIS — INTRODUCTION
Revision: August 20072004 QX56
TROUBLE DIAGNOSIS — INTRODUCTIONPFP:00000
IntroductionEDS0017W
DESCRIPTION
When a malfunction (indicated by the 4WD warning lamp illumination) occurs, collect information first from the
customer about how the malfunction occurs. Then, proceed with the diagnosis presuming it is the cause. Also
inspect the electrical system, paying close attention to other possibilities such as fluid level and leaks.
All-mode 4WD transfer is controlled by transfer control unit and sensors.
If a malfunction occurs in the all-mode 4WD system, the 4WD warning lamp lights up to inform of the system
malfunction. There are two ways to identify the cause of the malfunction.
1. Performing the self-diagnosis. (The 4WD warning lamp will indicate what kind of malfunction has occurred
by flickering.)
2. Performing diagnosis using CONSULT-II.
DIAGNOSTIC WORKSHEET
Information from Customer
KEY POINTS

WHAT ..... Vehicle model

WHEN..... Date, Frequencies

WHERE..... Road conditions

HOW..... Operating conditions, Symptoms
Diagnostic Worksheet
Information sheet from customer
Customer name MR/MS Model & Year VIN
Transfer model
AT X 1 4 BEngine Mileage
Incident Date Manuf. Date In Service Date
Frequency❏ Continuous ❏ Intermittent ( times a day)
Symptoms❏ 4WD shift indicator lamp does not turn on.
❏ 4WD warning lamp does not turn on.
❏ 4WD shift indicator lamp does not turn off.
❏ ATP warning lamp does not turn on.
❏ 4LO indicator lamp does not turn on.
❏ 4WD shift indicator lamp does not indicate “4H”.
❏ 4WD shift indicator lamp repeats flicking.
❏ Tight corner braking symptom occurs.
❏ 4WD system does not operate.
❏ Others.
4WD warning lamp❏ Continuously lit❏ Not lit
1.❏ Listen to customer complaints.TF-47
2.❏ Check transfer fluid.TF-47
❏ Leakage
❏ Fluid condition
❏ Fluid level
3.❏ Road testingTF-47
❏ 1. Check before engine is started.
❏ 2. Check at idle.
❏ 3. Cruise test
4.❏ Perform self-diagnosis NG items (with CONSULT-II and without CONSULT-II).TF-31
, TF-28

TF-48
TROUBLE DIAGNOSIS — BASIC INSPECTION
Revision: August 20072004 QX56
1. CHECK BEFORE ENGINE IS STARTED
1. CHECK 4WD SHIFT INDICATOR LAMP
1. Park vehicle on flat surface.
2. Turn ignition switch to OFF position.
3. Move A/T selector lever to P position.
4. Set 4WD shift switch to 4H position.
5. Set 4WD shift switch to 2WD position.
6. Turn ignition switch to ON position. (Do not start engine.)
7. Does 4WD shift indicator lamp turn ON for approx. 1 second?
Ye s o r N o
Yes >> GO TO 2.
No >> Go to Symptom 1. Refer to TF-85, "
Symptom 1. 4WD
Shift Indicator Lamp Does Not Turn ON (Although the
ignition switch is turned ON, all the 4WD indicator lamps
do not turn ON for 1 second)" .
2. CHECK 4WD WARNING LAMP
Is 4WD warning lamp turned ON?
Ye s o r N o
Yes >> 1. Turn ignition switch to OFF position.
2. Perform self-diagnosis.
Refer to TF-27, "
Trouble Diagnosis without CON-
SULT-II" .
3. Go to “2. CHECK AT IDLE”. Refer to TF-49, "
2.
CHECK AT IDLE" .
No >> Go to Symptom 2. Refer to TF-87, "
Symptom 2. 4WD
Warning Lamp Does Not Turn ON (Although the ignition
switch is turned ON, the 4WD warning lamp does not
turn ON)" .
LDIA0061E
WDIA0071E
WDIA0071E

TROUBLE DIAGNOSIS — BASIC INSPECTION
TF-49
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Revision: August 20072004 QX56
2. CHECK AT IDLE
1. CHECK 4WD SHIFT INDICATOR LAMP
1. Park vehicle on flat surface.
2. Turn ignition switch to OFF position.
3. Move A/T selector lever to P or N position.
4. Set 4WD shift switch to 4H position.
5. Set 4WD shift switch to 2WD position.
6. Start engine.
7. Is 4WD shift indicator lamp turned OFF?
Ye s o r N o
Yes >> Go to “ATP SWITCH, WAIT DETECTION SWITCH AND
NEUTRAL-4LO SWITCH”. Refer to TF-69, "
AT P
SWITCH, WAIT DETECTION SWITCH AND NEUTRAL-4LO SWITCH" .
No >> GO TO 2.
2. CHECK 4WD WARNING LAMP
Is 4WD warning lamp turned OFF?
Ye s o r N o
Yes >> GO TO 3.
No >> Perform self-diagnosis. Refer to TF-27, "
Trouble Diagnosis without CONSULT-II" .
WDIA0071E

TF-50
TROUBLE DIAGNOSIS — BASIC INSPECTION
Revision: August 20072004 QX56
3. CHECK 4WD SHIFT INDICATOR LAMP
1. Set 4WD shift switch to 2WD, AUTO, 4H, 4LO, 4H and 2WD in
order.
(Stay at each switch position for at least 1 second.)
2. Does 4WD shift indicator lamp change properly and does
buzzer sound?
Ye s o r N o
Yes >> GO TO 4.
No >> Go to “2-4WD SHIFT SOLENOID VALVE AND 4WD
SHIFT SWITCH”. Refer to TF-62, "
2-4WD SHIFT SOLE-
NOID VALVE AND 4WD SHIFT SWITCH" .
4. CHECK 4WD WARNING LAMP
Is 4WD warning lamp turned ON?
Ye s o r N o
Yes >> Perform self-diagnosis. Refer to TF-27, "Trouble Diagnosis without CONSULT-II" .
No >> GO TO 5.
LDIA0063E
LDIA0064E

TROUBLE DIAGNOSIS — BASIC INSPECTION
TF-51
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Revision: August 20072004 QX56
5. CHECK 4WD SHIFT INDICATOR LAMP
1. Move A/T selector lever to P position.
2. Set 4WD shift switch from 4H to 4LO.
3. While shifting from 4H to 4LO, does 4WD shift indicator lamp
turn OFF and ATP warning lamp turn ON?
Ye s o r N o
Yes >> GO TO 6.
No >> Go to Symptoms 3 and 4. Refer to TF-88, "
Symptom 3.
4WD Shift Indicator Lamp Does Not Turn OFF (When
4WD shift switch is set from 4H to 4LO, all the 4WD shift
indicator lamps do not turn off)" and TF-89, "Symptom
4. ATP Warning Lamp Does Not Turn ON (When 4WD
shift switch is set from 4H to 4LO with the A/T selector
lever in P position, the ATP warning lamp does not turn
on)" .
6. CHECK 4WD SHIFT INDICATOR LAMP
Do the 4WD shift indicator lamps indicate 4LO when the 4WD shift
switch is set in 4LO?
Ye s o r N o
Yes >> GO TO 7.
No >> Go to Symptom 5. Refer to TF-90, "
Symptom 5. 4LO Indicator Lamp Does Not Turn ON (When
4WD shift switch is set from 4H to 4LO position, 4LO indicator lamp does not turn ON)" .
LDIA0061E
WDIA0071E
LDIA0061E
WDIA0071E