2004 INFINITI QX56 transfer

ON BOARD DIAGNOSTIC SYSTEM DESCRIPTION
TF-41
C
E
F
G
H
I
J
K
L
MA
B
TF
Revision: August 20072004 QX56
WORK SUPPORT
Purpose
When there is no problem with transfer and 4WD system, the following symptom in “AUTO” mode may be
claimed by a customer.

Vibration when accelerating on snow-covered or icy roads. (Note)
AUTO indicator lamp
(AUTO IND)OFFEngine at rest during 2WD-mode operation or system out
of order
ON 4WD shift switch in “4LO” or “4H” or “AUTO” position
LOCK indicator lamp
(LOCK IND)OFFEngine at rest and 4WD shift switch in “AUTO” position
during 2WD-mode operation or system out of order
ON 4WD shift switch in “4H” or “4LO” position
4LO indicator lamp
(4L IND)OFFEngine at rest and 4WD shift switch in “AUTO” position
during 2WD-mode operation or system out of order
ON 4WD shift switch in “4LO” position
Clutch force release limit
(CL/F RLS LIM)0.2, 0.3, 1.2 kgmIndicates the clutch force release setting applied using the
scan tool. 0.3 kgm is the default setting.
VDC operation switch
(VDC OPER SW)OFF VDC is not operating.
ON VDC is operating.
TCS operation switch
(TCS OPER SW)OFF TCS is not operating.
ON TCS is operating.
ATP indicator lamp
(ATP IND)OFF Normal operation.
ONDriver is attempting to shift into or out of 4L while the AT is
not in neutral.
Transfer case F speed
(T/F F SPEED)0.0 km/h (0.0 MPH) —
Automatic transmission R speed
(AT R SPEED)0.0 km/h (0.0 MPH) —
Automatic transmission gear position
(AT GEAR POSI)1,2,3,4 Displays actual AT gear position. Indicated items
(Screen terms for CONSULT-II, “DATA
MONITOR” mode)Display Conditions

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

TROUBLE DIAGNOSIS — BASIC INSPECTION
TF-47
C
E
F
G
H
I
J
K
L
MA
B
TF
Revision: August 20072004 QX56
TROUBLE DIAGNOSIS — BASIC INSPECTIONPFP:00000
Listen to Customer ComplaintsEDS0017Y

Each customer feels differently about a problem. It is important to fully understand the symptoms or condi-
tions for a customer complaint.

Listen to the customer about how and when the malfunction occurs, and make good use of it when per-
forming the road test.
Transfer Fluid CheckEDS0017Z

Check fluid for leaks and fluid level. Refer to TF-47, "Transfer Fluid Check" .
Road TestEDS00180
PREPARATION FOR ROAD TEST

The purpose of the test is to determine overall performance of
transfer and analyze causes of problems.

When a malfunction is found in any part of transfer, perform the
road test to locate the malfunction area and repair the malfunc-
tion parts.

The road test consists of the following three parts:
1. Check before engine is started
2. Check at idle
3. Cruise test

Perform road test and place checks for NG items on the diag-
nostic worksheet. Refer to TF-44, "
Diagnostic Worksheet" .
SMT089D

TROUBLE DIAGNOSIS — GENERAL DESCRIPTION
TF-55
C
E
F
G
H
I
J
K
L
MA
B
TF
Revision: August 20072004 QX56
TROUBLE DIAGNOSIS — GENERAL DESCRIPTIONPFP:00000
Transfer Control Unit Terminals and Reference ValueEDS00181
TRANSFER CONTROL UNIT HARNESS CONNECTOR LAYOUT
TRANSFER CONTROL UNIT INSPECTION TABLE
LDIA0066E
Te r m i n a l
No.Item ConditionJudgement standard
(Approx.)
12-4WD shift solenoid
valve &4WD shift switch is set to 2WD posi-
tion.Less than 1V
4WD shift switch is set to any posi-
tion other than 2WD.Battery voltage
24WD shift indicator lamp
(2WD)Lamp lights while system is operating
properly.Less than 1V
&2WD indicator lamp does not come
on.Battery voltage
3Ground — —
4 Transfer shift relay (High)While actuator is operating (4H →
4LO)Battery voltage
Actuator does not operate. Less than 1V
5 4WD warning lampLamp comes ON (when engine is
stopped).
(Fail-safe condition appears on dis-
play, engine is stopped, actuator
position detection switch is inopera-
tive, oil temperature is too high and/
or tires of different size are installed.)Less than 1V
Except above Battery voltage
6Ground — — —
7CAN-H — — —
8CAN-L — — —
9 4WD shift switch (2WD)
&4WD shift switch is set to 2WD posi-
tion.Battery voltage
4WD shift switch is set to any posi-
tion other than 2WD.Less than 1V
10 Transfer dropping resistor4WD shift switch is set to AUTO posi-
tion.4 - 14V
4WD shift switch is set to any posi-
tion other than 2WD.Less than 1V

TF-56
TROUBLE DIAGNOSIS — GENERAL DESCRIPTION
Revision: August 20072004 QX56
114WD shift indicator lamp
(4H)“4H” indicator lamp comes ON. Less than 1V
4WD shift switch is set to any posi-
tion other than 4H.Battery voltage
124WD shift indicator lamp
(4LO)“4LO” indicator lamp comes ON. 0V
4WD shift switch is set to any posi-
tion other than 4LO.Battery voltage
13 Transfer shift relay (Low)
&While actuator is operating (4LO →
4H)Battery voltage
Actuator does not operate. 0V
14 Transfer motor relayTransfer motor relay is ON. Battery voltage
Transfer motor relay is OFF. Less than 1V
15 ATP lampAT selector lever is set to P position. Battery voltage
AT selector lever is set to any posi-
tion other than P.0V
16 Power supply —Ignition key is set to ON position. Battery voltage
Ignition key is set to OFF position. 0V
18 4WD shift switch (4H)
&4WD shift switch is set to 4H posi-
tion.Battery voltage
4WD shift switch is set to any posi-
tion other than 4H.Less than 1V
19 4WD solenoid valve4WD shift switch is set to AUTO posi-
tion.1.5 - 3V
4WD shift switch is set to any posi-
tion other than 2WD.Less than 1V
214WD shift indicator lamp
(AUTO)“AUTO” indicator lamp comes ON. 0V
4WD shift switch is set to any posi-
tion other than AUTO.Battery voltage
22 Power supply —Ignition key is set to ON position. Battery voltage
Ignition key is set to OFF position. 0V
23 4WD shift switch (4LO)
&4WD shift switch is set to 4LO posi-
tion.Battery voltage
4WD shift switch is set to any posi-
tion other than 4LO.Less than 1V
24 4WD shift switch (AUTO)4WD shift switch is set to AUTO posi-
tion.Battery voltage
4WD shift switch is set to any posi-
tion other than AUTO.Less than 1V
25 Neutral-4LO switchTransfer is set to 4LO position. 0V
Transfer is set to any position other
than 4LO.Battery voltage
27Transfer 4H actuator
switch4WD shift switch is set to 4H posi-
tion.Less than 1V
4WD shift switch is set to any posi-
tion other than 4H.Battery voltage
28 Sensor ground — Less than 1V Te r m i n a l
No.Item ConditionJudgement standard
(Approx.)

TROUBLE DIAGNOSIS — GENERAL DESCRIPTION
TF-57
C
E
F
G
H
I
J
K
L
MA
B
TF
Revision: August 20072004 QX56
30Power supply for A/D
converter &Ignition key is set to ON position. 4.5 - 5.5V
Ignition key is set to OFF position. 0V
31Transfer fluid tempera-
ture sensor &At 20°C (68°F) 1.1V
At 80°C (176°F) 0.3V
33 Transfer shift relay (High)
&While actuator is operating from “4H”
to “4LO”Battery voltage
Actuator does not operate. 0V
34 Clutch pressure switch4WD shift switch is set to AUTO or
4H, then A/T selector lever is set to D
position. (wait detection system:
OFF)Battery voltage
4WD shift switch is set to 2WD,
AUTO or 4H, then A/T selector lever
is set to D position. (wait detection
system: ON)0V
35 Line pressure switch4WD shift switch is set to 2WD,
AUTO or 4H, then A/T selector lever
is set to D position.Battery voltage
—0V
36 CONSULT-II (RX) — — —
40 ATP switch
&A/T selector lever is set to P position. Battery voltage
A/T selector lever is set to any posi-
tion other than P.Less than 1V
41Transfer motor relay
monitorTransfer motor relay is ON. Battery voltage
Transfer motor relay is OFF. Less than 1V
42Transfer shift relay
(LOW)While actuator is operating from
“4LO” to “4H” positionBattery voltage
Actuator does not operate. 0V
43 Wait detection switch4WD shift switch is set to any posi-
tion other than 4LO.Battery voltage
4WD shift switch is set to 4LO posi-
tion.*3Less than 1V
44Transfer 4LO actuator
switch4WD shift switch is set to any posi-
tion other than 4LO. (Actuator: High
position)Battery voltage
4WD shift switch is set to 4LO posi-
tion. (Actuator: Low position)Less than 1V
45 Ground — — — Te r m i n a l
No.Item ConditionJudgement standard
(Approx.)

DTC U1000, U1001 CAN COMMUNICATION LINE
TF-59
C
E
F
G
H
I
J
K
L
MA
B
TF
Revision: August 20072004 QX56
DTC U1000, U1001 CAN COMMUNICATION LINEPFP:23710
CAN Communication System InspectionEDS00182
INSPECTION PROCEDURE
1. PERFORM SELF-DIAGNOSIS
Perform transfer control unit self-diagnosis.
Is
“CAN COMM CIRCUIT” displayed in the self-diagnosis display items?
Yes >> Print out the self-diagnosis results and go to 2.
No >> Inspection End.
2. CONNECTOR INSPECTION
1. Disconnect the transfer control unit connectors E142 and E143.
2. Check the terminals for deformation, disconnection, looseness or damage.
OK or NG
OK >> GO TO 3.
NG >> Repair or replace as necessary.
3. CAN COMMUNICATION SYSTEM CHECK
Check the data monitor item “CAN Diagnosis Support Monitor”.
>> After printing out the monitor items, go to CAN system. Refer to LAN-3, "
Precautions When Using
CONSULT-II" .

TF-60
4WD SOLENOID VALVE
Revision: August 20072004 QX56
4WD SOLENOID VALVEPFP:00000
Diagnostic ProcedureEDS00183
1. CHECK 4WD SOLENOID VALVE
Refer to TF-95, "
4WD SOLENOID VALVE, CLUTCH PRESSURE
SWITCH AND LINE PRESSURE SWITCH" .
OK or NG
OK >> GO TO 2.
NG >> Repair or replace 4WD solenoid valve.
2. CHECK POWER SOURCE CIRCUIT
1. Turn ignition switch to OFF position.
2. Disconnect transfer control unit harness connector E142.
3. Check resistance between transfer terminal cord assembly har-
ness connector F56 terminal 6 (L) and transfer control unit har-
ness connector E142 terminal 10 (L/W).
OK or NG
OK >> GO TO 3.
NG >> Check the following.

Transfer dropping resistor
Refer to TF-96, "
TRANSFER DROPPING RESISTOR" .

Continuity between transfer terminal cord assembly harness connector F56 terminal 6 (L) and
transfer dropping resistor harness connector E135 terminal 2 (L).

Continuity between transfer dropping resistor harness connector E135 terminal 1 (L/W) and
transfer control unit harness connector E142 terminal 10 (L/W).
3. CHECK POWER SOURCE CIRCUIT
1. Turn ignition switch to OFF position.
2. Check continuity between transfer terminal cord assembly har-
ness connector F56 terminal 6 (L) and transfer control unit har-
ness connector E142 terminal 19 (L).
Continuity should exist.
OK or NG
OK >> GO TO 4.
NG >> Repair or replace harness between transfer terminal
cord assembly harness connector F56 terminal 6 (L)
and transfer control unit harness connector E142 termi-
nal 19 (L).
SMT775D
Resistance : 11.2 - 12.8Ω
LDIA0067E
LDIA0068E