Ins INFINITI QX56 2004 Factory Service Manual

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
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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

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
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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
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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
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WDIA0071E

TF-52
TROUBLE DIAGNOSIS — BASIC INSPECTION
Revision: August 20072004 QX56
7. CHECK 4WD SHIFT INDICATOR LAMP (*1)
1. Set 4WD shift switch from 4LO to 4H.
2. Does 4LO indicator lamp flicker? (*1)
*1: While “Wait” function is operating, 4LO indicator lamp flashes.
Ye s o r N o
Yes >> Go to Symptoms 6 and 7. Refer to TF-91, "Symptom 6. 4WD Shift Indicator Lamp Does Not Indi-
cate “LOCK” (When 4WD shift switch is set to “4H”, 4WD shift indicator lamp does not indicate
“LOCK”)" and TF-92, "Symptom 7. 4WD Shift Indicator Lamp Repeats Flickering (4WD Shift Indi-
cator Lamp Keeps Flickering)" .
No >> Go to “3. CRUISE TEST”. Refer to TF-53, "
3. CRUISE TEST" .

TROUBLE DIAGNOSIS — BASIC INSPECTION
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3. CRUISE TEST
1. INSPECTION START
Do you have CONSULT-II?
Ye s o r N o
Yes >> GO TO 2.
No >> GO TO 3.
2. CHECK INPUT SIGNAL
With CONSULT-II
1. Warm up engine to normal operating temperature.
2. Park vehicle on flat surface.
3. Set 4WD shift switch to 4H position.
4. Set 4WD shift switch to AUTOposition.
5. Start engine.
6. Drive for at least 30 seconds at a speed higher than 20 km/h (12 MPH).
(Drive vehicle until “FLUID TEMP SE” exceeds 0.9V.)
7. Park vehicle on flat surface.
8. Set 4WD shift switch to 2WD position.
9. Leave vehicle for at least 80 seconds with “FLUID TEMP SE” at
0.9V or less.
10. Is 4WD warning lamp turned ON?
Ye s o r N o
Yes >> Perform self-diagnosis. Refer to TF-31, "Trouble Diag-
nosis with CONSULT-II" .
No >> GO TO 4.
3. CHECK INPUT SIGNAL
Without CONSULT-II
1. Warm up engine to normal operating temperature.
2. Park vehicle on flat surface.
3. Set 4WD shift switch to 4H position.
4. Set 4WD shift switch to AUTO position.
5. Start engine.
6. Drive vehicle for at least 30 seconds at a speed higher than 20 km/h (12 MPH).
7. Park vehicle on flat surface.
8. Set 4WD shift switch to 2WD position.
9. 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 4.
SMT972D

TF-54
TROUBLE DIAGNOSIS — BASIC INSPECTION
Revision: August 20072004 QX56
4. (1) CHECK TIGHT CORNER BRAKING SYMPTOM
1. Set 4WD shift switch to AUTO position.
2. Drive vehicle at speed lower than 20 km/h (12 MPH) with steering wheel fully turned.
3. Does tight corner braking symptom occur?
Ye s o r N o
Yes >> GO TO 5.
No >> GO TO 6.
5. CONFIRM SYMPTOM AGAIN
Confirm symptom and self-diagnosis again.
Refer to TF-27, "
Trouble Diagnosis without CONSULT-II" and TF-31, "Trouble Diagnosis with CONSULT-II" .
OK or NG
OK >> GO TO 6.
NG >> Go to Symptoms 8 and 9. Refer to TF-93, "
Symptom 8. Tight Corner Braking Symptom (Tight Cor-
ner Braking Symptom Occurs-Hydraulic System Failure)" and TF-94, "Symptom 9. 4WD System
Does Not Operate (The Vehicle Cannot Be Put Into 4WD Mode-Hydraulic System Failure)" .
6. (2) CHECK TIGHT CORNER BRAKING SYMPTOM
1. Set 4WD shift switch to 4H position.
2. Drive vehicle at speed lower than 20 km/h (12 MPH) with steering wheel fully turned.
3. Does tight corner braking symptom occur?
Ye s o r N o
Yes >> Inspection End.
No >> GO TO 7.
7. CONFIRM SYMPTOM AGAIN
Confirm symptom and self-diagnosis again.
Refer to TF-27, "
Trouble Diagnosis without CONSULT-II" and TF-31, "Trouble Diagnosis with CONSULT-II" .
OK or NG
OK >> Inspection End.
NG >> Go to Symptoms 8 and 9. Refer to TF-93, "
Symptom 8. Tight Corner Braking Symptom (Tight Cor-
ner Braking Symptom Occurs-Hydraulic System Failure)" and TF-94, "Symptom 9. 4WD System
Does Not Operate (The Vehicle Cannot Be Put Into 4WD Mode-Hydraulic System Failure)" .

TROUBLE DIAGNOSIS — GENERAL DESCRIPTION
TF-55
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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