2009 INFINITI QX56 ECU

HOOD
DLK-231
< ON-VEHICLE REPAIR > [WITH INTELLIGENT KEY SYSTEM]
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Removal and Installation of Hood Lock ControlINFOID:0000000003775853
REMOVAL
1. Remove the bolts and the hood lock assembly.
2. Remove the front fender protector (LH). Refer to EXT-23, "
Removal and Installation".
3. Disconnect the hood lock primary and secondary hood lock cables from the hood lock. Unclip the primary
cable from the radiator core support upper and hood ledge.
4. Remove the hood lock assembly.
5. Remove the nuts and the secondary hood lock release assembly.
6. Remove the grommet from the dash lower, and pull the primary hood lock cable into the passenger room. CAUTION:
While pulling, be careful not to dama ge the outside of the hood lock cable.
INSTALLATION
1. Pull the hood lock cable through the dash lower hole into the engine room.
Be careful not to bend the cable too much, keeping the radius
100mm (3.94 in) or more.
2. Make sure the cable is not of fset from the positioning grommet,
and push the grommet into the dash lower hole securely.
3. Apply sealant around the grommet at * mark.
1. Hood lock assembly 2. Secondary hood lock release as-
sembly 3. Secondary hood lock cable
4. Primary hood lock cable 5. Grommet6. Hood lock release handle
WIIA0900E
PIIA0173E
Revision: December 20092009 QX56

DLK-232
< ON-VEHICLE REPAIR >[WITH INTELLIGENT KEY SYSTEM]
HOOD
4. Install the primary and secondary cables securely to the hood
lock.
5. Install the hood lock and the secondary hood lock release assemblies.
6. Check the hood lock adjustment and hood opener operation. Refer to DLK-229, "
Fitting Adjustment".
7. Install the remaing componets in the reverse order of removal.
Hood Lock Control InspectionINFOID:0000000003775854
CAUTION:
If the hood lock cable is bent or deformed, replace it.
1. Remove the front grille. Refer to EXT-17, "
Removal and Installation".
2. Make sure the secondary latch is properly engaged with the sec- ondary striker with hood's own weight by dropping it from
approx. 200 mm (7.87 in) height.
3. While operating the hood opener, carefully make sure the front end of the hood is raised by approx. 20 mm (0.79 in). Also make
sure the hood opener returns to the original position.
4. Check the hood lock lubrication condition. If necessary, apply “body grease” to the points shown in the figure.
5. Install the front grille. Refer to EXT-17, "
Removal and Installa-
tion".
Hood Stay DisposalINFOID:0000000005877751
1. Fix hood stay (1) using a vise (C).
2. Using hacksaw (A) slowly make 2 holes in the hood stay, in numerical order as shown in the figure.
CAUTION:
• When cutting a hole on hood stay, always cover a hack-saw using a shop cloth (B) to avoid scattering metal frag-
ments or oil.
• Wear eye protection (safety glasses).
• Wear gloves.
PIIA0174E
PIIA1086E
PIIA0176E
JMKIA3336ZZ
Revision: December 20092009 QX56

DLN-2
P1820 ENGINE SPEED SIGNAL ......................52
Description ........................................................... ...52
DTC Logic ...............................................................52
Diagnosis Procedure ..............................................52
P1822 CLUTCH PRESSURE SOLENOID .........53
Description ........................................................... ...53
DTC Logic ...............................................................53
Diagnosis Procedure ..............................................53
Component Inspection ............................................55
P1823 2-4 SOLENOID .......................................57
Description ........................................................... ...57
DTC Logic ...............................................................57
Diagnosis Procedure ..............................................57
Component Inspection ............................................60
P1824 TRANSFER MOTOR ..............................61
Description ........................................................... ...61
DTC Logic ...............................................................61
Diagnosis Procedure ..............................................61
Component Inspection ............................................65
P1826 TRANSFER FLUID TEMPERATURE ....67
Description ........................................................... ...67
DTC Logic ...............................................................67
Diagnosis Procedure ..............................................67
Component Inspection ............................................68
P1827 CLUTCH PRESSURE SWITCH .............70
Description ........................................................... ...70
DTC Logic ...............................................................70
Diagnosis Procedure ..............................................70
Component Inspection ............................................71
P1828 LINE PRESSURE SWITCH ....................73
Description ........................................................... ...73
DTC Logic ...............................................................73
Diagnosis Procedure ..............................................73
Component Inspection ............................................75
P1829 THROTTLE POSITION SIGNAL (ECM)
...
76
Description ........................................................... ...76
DTC Logic ...............................................................76
Diagnosis Procedure ..............................................76
P1830 ABS OPERATION SIGNAL (ABS) ........77
Description ........................................................... ...77
DTC Logic ...............................................................77
Diagnosis Procedure ..............................................77
P1831 VDC OPERATION SIGNAL (ABS) ........78
Description ........................................................... ...78
DTC Logic ...............................................................78
Diagnosis Procedure ..............................................78
P1832 TCS OPERATION SIGNAL (ABS) .........79
Description ........................................................... ...79
DTC Logic ...............................................................79
Diagnosis Procedure ..............................................79
U1010 CONTROL UNIT (CAN) .........................80
Description ........................................................... ...80
DTC Logic ...............................................................80
Diagnosis Procedure ...............................................80
ECU DIAGNOSIS .......................................81
TRANSFER CONTROL UNIT ........................ ...81
Reference Value .................................................. ...81
Wiring Diagram .......................................................89
DTC Index ...............................................................97
SYMPTOM DIAGNOSIS ...........................102
4WD SYSTEM SYMPTOMS ........................... ..102
Symptom Table .................................................... .102
4WD SHIFT INDICATOR LAMP AND 4LO IN-
DICATOR LAMP DO NOT TURN ON ..............
103
Description ........................................................... .103
Diagnosis Procedure .............................................103
4WD WARNING LAMP DOES NOT TURN ON ..105
Description ........................................................... .105
Diagnosis Procedure .............................................105
4WD SHIFT INDICATOR LAMP OR 4LO INDI-
CATOR LAMP DO NOT CHANGE ...................
107
Description ........................................................... .107
Diagnosis Procedure .............................................107
ATP WARNING LAMP DOES NOT TURN ON ..109
Description ........................................................... .109
Diagnosis Procedure .............................................109
4WD SHIFT INDICATOR LAMP KEEPS
FLASHING ........................................................
111
Description ........................................................... .111
Diagnosis Procedure .............................................111
4WD WARNING LAMP FLASHES RAPIDLY ..112
Description ............................................................112
Diagnosis Procedure .............................................112
4WD WARNING LAMP FLASHES SLOWLY ..113
Description ............................................................113
Diagnosis Procedure .............................................113
HEAVY TIGHT-CORNER BRAKING SYMP-
TOM OCCURS ................................................ ..
114
Description ........................................................... .114
Diagnosis Procedure .............................................114
ATP SWITCH ....................................................116
Description ........................................................... .116
Diagnosis Procedure .............................................116
4WD SYSTEM DOES NOT OPERATE ............118
Description ........................................................... .118
Diagnosis Procedure .............................................118
Revision: December 20092009 QX56

DLN-18
< FUNCTION DIAGNOSIS >[ATX14B]
DIAGNOSIS SYSTEM (T
RANSFER CONTROL UNIT)
DIAGNOSIS SYSTEM (TRA NSFER CONTROL UNIT)
CONSULT-III Function (ALL MODE AWD/4WD)INFOID:0000000003772079
FUNCTION
CONSULT-III can display each diagnostic item us ing the diagnostic test modes shown following.
SELF-DIAG RESULT MODE
Operation Procedure
1. Connect CONSULT-III.
2. With engine at idle, touch SELF-DIAG RESULTS.
Display shows malfunction experienced since the last erasing operation.
NOTE:
The details for TIME are as follows:
 0: Error currently detected with transfer control unit.
 Except for 0: Error detected in the pa st and memorized with transfer control unit.
Detects frequency of driving after DTC occurs (frequency of turning ignition switch ON/OFF).
How to Erase Self-d iagnostic Results
1. Perform applicable inspection of malfunctioning item and then repair or replace.
2. Start engine and select SELF-DIAG RESULTS m ode for ALL MODE AWD/4WD with CONSULT-III.
3. Touch ERASE on CONSULT-III screen to erase DTC memory. CAUTION:
If memory cannot be erased, pe rform applicable diagnosis.
SELF-DIAGNOSTIC PROCEDURE (WITHOUT CONSULT-III)
Description
If the engine starts when there is a malfunction in the 4W D system, the 4WD warning lamp turns ON or flickers
in the combination meter. When the system functions properly, the warning lamp turns ON when the ignition
switch is turned to ON, and it turns OFF after engine starts . To locate the cause of a malfunction, start the self-
diagnosis function. The 4WD warning lamp in the co mbination meter will indicate the malfunction area by
flashing according to the self-diagnostic results. Refer to DLN-97, "DTC Index"
.
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.
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.
ALL MODE AWD/4WD diagnostic mode Description
SELF-DIAG RESULTS Displays transfer control unit self-diagnosis results.DATA MONITOR Displays transfer control unit input/output data in real time.
WORK SUPPORT Supports inspections and adjustments. Commands are transmitted to the transfer control
unit for setting the status suitable for required operation, input/output signals are received
from the transfer control unit and received data is displayed.
CAN DIAG SUPPORT MNTR The results of transmit/receive diagnosis of CAN communication can be read. ECU PART NUMBER Transfer control unit part number can be read.
Revision: December 20092009 QX56

DIAGNOSIS SYSTEM (TRANSFER CONTROL UNIT)
DLN-19
< FUNCTION DIAGNOSIS > [ATX14B]
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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.
Self-diagnosis example
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 igni tion switch OFF after performing self-diagnostics or by
erasing the memory using the CONSULT-III.
DATA MONITOR MODE
Operation Procedure
1. Connect CONSULT-III.
2. Touch DATA MONITOR.
3. Select from SELECT MONITOR ITEM, screen of data monitor mode is displayed.
NOTE:
When malfunction is detected, CONSUL T-III performs REAL-TIME DIAGNOSIS.
Also, any malfunction detected while in th is mode will be displayed at real time.
Display Item List
×: Standard –: Not applicable
PDIA0227E
Monitored item (Unit) Monitor item selection
Remarks
ECU INPUT
SIGNALS MAIN
SIGNALS SELEC-
TION FROM MENU
VHCL/S SEN·FR [km/h] or [mph] ×–×Wheel speed calculated by ABS actuator and
electric unit (control unit).
Signal input with CAN communication line.
VHCL/S SEN·RR [km/h] or [mph] ×–×Wheel speed calculated by TCM.
Signal input with CAN communication line.
ENGINE SPEED [rpm] ×–×Engine speed calculated by ECM.
Signal input with CAN communication line.
THRTL POS SEN [V] ×–×Accelerator peda
l position (APP) sensor sig-
nal voltage is displayed.
Signal input with CAN communication line.
FLUID TEMP SE [V] ×–×Transfer fluid temperature sensor signal volt-
age is displayed.
BATTERY VOLT [V] ×–×Power supply voltage for transfer control unit.
2WD SWITCH [ON/OFF] ×–×4WD shift switch status is displayed.
AUTO SWITCH [ON/OFF] ×–×4WD shift switch status is displayed.
LOCK SWITCH [ON/OFF] ×–×4WD shift switch status is displayed.
(LOCK means 4H of 4WD shift switch.)
Revision: December 20092009 QX56

DLN-20
< FUNCTION DIAGNOSIS >[ATX14B]
DIAGNOSIS SYSTEM (T
RANSFER CONTROL UNIT)
4L SW [ON/OFF] ×–×4WD shift switch status is displayed.
(4L means 4LO of 4WD shift switch.)
N POSI SW TF [ON/OFF] ×–×Neutral-4LO switch signal status is displayed.
ATP SWITCH [ON/OFF] ×–×ATP switch signal status is displayed.
WAIT DETCT SW [ON/OFF] ×–×Wait detection switch status is displayed.
LINE PRES SW [ON/OFF] ×–×Line pressure switch status is displayed.
CL PRES SW [ON / OFF] ×–×Clutch pressure switch status is displayed.
N POSI SW AT [ON/OFF] ×–×N position signal of transmission range switch
status is displayed.
Signal input with CAN communication line.
R POSI SW AT [ON/OFF] ×–×R position signal of transmission range switch
status is displayed.
Signal input with CAN communication line.
P POSI SW AT [ON/OFF] ×–×P position signal of transmission range switch
status is displayed.
Signal input with CAN communication line.
ABS OPER SW [ON/OFF] ×–×ABS operation signal status is displayed.
Signal input with CAN communication line.
VDC OPER SW [ON/OFF] ×–×VDC operation signal status is displayed.
Signal input with CAN communication line.
TCS OPER SW [ON/OFF] ×–×TCS operation signal status is displayed.
Signal input with CAN communication line.
THROTTLE POSI [0.0/8] – ××Thottle position status is displayed.
Signal input with CAN communication line.
4WD MODE [AUTO/LOCK/2WD/4L] – ××Control status of 4WD recognized by transfer
control unit. (AUTO, 4H, 2WD or 4LO)
VHCL/S COMP [km/h] or [mph] – ××Vehicle speed recognized by transfer control
unit.
COMP CL TORQ [kgm] – ××Calculated torque recognized by transfer con-
trol unit.
DUTY SOLENOID [%] – ××Control value of clutch pressure solenoid.
2-4WD SOL [ON/OFF] – ××Output condition to 2-4WD solenoid.
2-4WD SOL MON [ON/OFF] – – ×Check signal for transfer control unit signal
output.
MOTOR RELAY [ON/OFF] – ××Transfer motor relay signal status is dis-
played.
MOTOR RELAY MON [ON/OFF] – – ×
Check signal for transfer control unit signal
output.
4WD FAIL LAMP [ON/OFF] – ××Control status of 4WD warning lamp is dis-
played.
2WD IND [ON/OFF] – – ×Control status of 4WD shift indicator lamp
(2WD indicator lamp) is displayed.
AUTO IND [ON/OFF] – – ×Control status of 4WD shift indicator lamp
(2WD and AUTO indicator lamp) is displayed.
LOCK IND [ON/OFF] – – ×Control status of 4WD shift indicator lamp
(2WD, AUTO and Lock indicator) is displayed.
4L IND [ON/OFF] – – ×Control status of 4LO indicator lamp is dis-
played.
Monitored item (Unit)
Monitor item selection
Remarks
ECU INPUT
SIGNALS MAIN
SIGNALS SELEC-
TION FROM
MENU
Revision: December 20092009 QX56

DIAGNOSIS SYSTEM (TRANSFER CONTROL UNIT)
DLN-21
< FUNCTION DIAGNOSIS > [ATX14B]
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WORK SUPPORT
When there is no malfunction with transfer and 4WD sys tem, the following symptoms in AUTO mode may be
claimed by a customer: vibration when accelerating on a low µ road (snow-covered or icy road) or a slight
shock is felt at a few hertz as if it were being pushed lightly from behind.
It is possible to deal with these symptoms by c hanging the CLUTCH FORCE RELEASE LIMIT VALUE. How-
ever, be careful when changing the value because it may adversely affect driving performance.
Operation Procedure
1. Connect CONSULT-III.
2. Touch WORK SUPPORT.
3. Select from CLUTCH/F RLS LIM ADJ, screen of data monitor mode is displayed.
Clutch Force Release Limit Adjustment
1. Initial CLUTCH FORCE RELEASE LIMIT value 0.3 kgm appears under CONDITION SETTING on CON-
SULT-III display.
2. Touch 1.2 on the display.
3. Display changes to NOW ADJUSTING in a short time.
4. When clutch force release limit value is set to 1. 2 kgm, current value 0.3 kgm shown on display will be
replaced by 1.2 kgm and ADJUSTME NT COMPLETE will appear at the same time. Clutch force release
limit value setting is now complete.
ATP IND [ON/OFF] – – ×Control status of ATP warning lamp is dis-
played.
SHIFT POS SW1 [ON/OFF] ×–×Actuator position switch 1 (Low) signal status
is displayed.
SHIFT POS SW2 [ON/OFF] ×–×Actuator position switch 2 (high) signal status
is displayed.
SHIFT ACT1 [ON/OFF] – ××Output condition to actuator motor (clockwise)
SHIFT AC MON1 [ON/OFF] ×–×Check signal for transfer control unit signal
output
SHIFT ACT2 [ON/OFF] – ××Output condition to actuator motor (counter-
clockwise)
SHIFT AC MON2 [ON/OFF] ×–×Check signal for transfer control unit signal
output
T/F F SPEED [km/h] or [mph] ×–×Displayed, but do not use.
A/T R SPEED [km/h] or [mph] ×–×Output shaft revolution signal (output speed
sensor) calculated by TCM.
Signal input with CAN communication line.
AT GEAR POSI [1/2/3/4/5] ×–×A/T actual gear position is displayed.
Monitored item (Unit)
Monitor item selection
Remarks
ECU INPUT
SIGNALS MAIN
SIGNALS SELEC-
TION FROM
MENU
1.2 kg-m : Tight corner braking symptom is alleviated. However, vibration may occur when acceler-
ating on a low µ road (icy road, etc.).
0.3 kg-m : Initial set value.
0.2 kg-m : Do not set to th is value because the tight
corner braking symptom will get worse.
Revision: December 20092009 QX56

TRANSFER CONTROL UNITDLN-81
< ECU DIAGNOSIS > [ATX14B]
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ECU DIAGNOSIS
TRANSFER CONTROL UNIT
Reference ValueINFOID:0000000003772158
VALUE ON THE DIAGNOSIS TOOL
CONSULT-III data monitor item
Monitored item [Unit] Content Condition Display value
VHCL/S SEN·FR [km/h]
or [mph] Wheel speed (Front
wheel) Vehicle stopped 0 km/h (0 mph)
Vehicle running
CAUTION:
Check air pressure of tire under standard condition.
Approximately
equal to the indica-
tion on speedome-
ter (Inside of
±
10%)
VHCL/S SEN·RR [km/h]
or [mph] Wheel speed (Rear
wheel) Vehicle stopped 0 km/h (0 mph)
Vehicle running
CAUTION:
Check air pressure of tire under standard condition.
Approximately
equal to the indica-
tion on speedome-
ter (Inside of
±
10%)
ENGINE SPEED [rpm ] Engine speed Engine stopped
(Engine speed: Less than 400 rpm)
0 rpm
Engine running
(Engine speed: 400 rpm or more) Approximately
equal to the indica-
tion on tachometer
THRTL POS SEN [V] Accelertor pedal position
(APP) sensor signal volt-
age Accelerator pedal: Released Approx. 0.5V
Accelerator pedal: Fully depressed Approx. 4.0V
FLUID TEMP SE [V] Transfer fluid tempera-
ture signal voltage Transfer fluid temperature approx. 20 - 80
°C (68 - 176 °F) Approx. 1.1 - 0.3V
BATTERY VOLT [V] Power supply voltage for
transfer control unit Ignition switch: ON Battery voltage
2WD SWITCH [ON/OFF] Input condition from 4WD
shift switch 4WD shift switch: 2WD ON
4WD shift switch: AUTO, 4H or 4LO OFF
AUTO SWITCH [ON/
OFF] Input condition from 4WD
shift switch 4WD shift switch: AUTO ON
4WD shift switch: 2WD, 4H or 4LO OFF
LOCK SWITCH [ON/
OFF] Input condition from 4WD
shift switch 4WD shift switch: 4H ON
4WD shift switch: 2WD, AUTO or 4LO OFF
4L SWITCH [ON/OFF] Input condition from 4WD
shift switch 4WD shift switch: 4LO ON
4WD shift switch: 2WD, AUTO or 4H OFF
N POSI SW TF [ON/
OFF] Condition of neutral-4LO
switch  Vehicle stopped
 Engine running
 A/T selector lever N posi-
tion
 Brake pedal depressed 4WD shift switch: 2WD,
AUTO or 4H
OFF
4WD shift switch: 4H to
4LO (While actuator mo-
tor is operating.) OFF
→ON
4WD shift switch: 4LO to
4H (While actuator motor
is operating.) ON
→OFF
4WD shift switch: 4LO ON
Revision: December 20092009 QX56