2004 INFINITI QX56 Can communication

TROUBLE DIAGNOSIS FOR SYMPTOMS
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Vehicle Does Not Creep Forward In “D” PositionUCS002IO
SYMPTOM:
Vehicle does not creep forward when selecting “D” position.
DIAGNOSTIC PROCEDURE
1. CHECK SELF-DIAGNOSTIC RESULTS
Perform self-diagnosis. Refer to AT- 9 3 , "
SELF-DIAGNOSTIC RESULT MODE" .
Do the self-diagnostic results indicate accelerator pedal position sensor, CAN communication line, PNP
switch?
YES >> Check the malfunctioning system. Refer to AT-129, "DTC P1705 THROTTLE POSITION SEN-
SOR" , AT - 1 0 3 , "DTC U1000 CAN COMMUNICATION LINE" , AT-109, "DTC P0705 PARK/NEU-
TRAL POSITION SWITCH" .
NO >> GO TO 2.
2. CHECK CONTROL CABLE
Check the control cable.

Refer to AT- 2 3 4 , "Checking of A/T Position" .
OK or NG
OK >> GO TO 3.
NG >> Adjust control cable. Refer to AT-234, "
Adjustment of A/
T Position" .
3. CHECK A/T FLUID LEVEL
Check A/T fluid level. Refer to AT- 1 3 , "
Checking A/T Fluid" .
OK or NG
OK >> GO TO 4.
NG >> Refill ATF.
4. CHECK STALL TEST
Check stall revolution with selector lever in “D” position. Refer to AT-
58, "STALL TEST" .
OK or NG
OK >> GO TO 5.
NG >> GO TO 7.
LCIA0324E
SAT6 3 8A
SAT4 9 3G

TROUBLE DIAGNOSIS FOR SYMPTOMS
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10. PERFORM TCM INSPECTION
1. Perform TCM input/output signals inspection. Refer to AT-90, "
TCM Input/Output Signal Reference Val-
ues" .
2. If NG, recheck A/T assembly harness connector terminals for damage or loose connection with harness
connector.
OK or NG
OK >>INSPECTION END
NG >> Repair or replace damaged parts.
11 . DETECT MALFUNCTIONING ITEM

Check the malfunction items. If any items are damaged, repair or replace damaged parts. Refer to AT-68,
"Symptom Chart" (Symptom No.13).
OK or NG
OK >> GO TO 9.
NG >> Repair or replace damaged parts.
A/T Does Not Perform Lock-upUCS002IU
SYMPTOM:
A/T does not perform lock-up at the specified speed.
DIAGNOSTIC PROCEDURE
1. CHECK SELF-DIAGNOSTIC RESULTS
Perform self-diagnosis. Refer to AT- 9 3 , "
SELF-DIAGNOSTIC RESULT MODE" .
Do the self-diagnostic results indicate torque converter clutch solenoid valve, engine speed signal, turbine rev-
olution sensor, accelerator pedal position sensor, CAN communication?
YES >> Check the malfunctioning system. Refer to AT- 11 8 , "DTC P0740 TORQUE CONVERTER
CLUTCH SOLENOID VALVE" , AT-115, "DTC P0725 ENGINE SPEED SIGNAL" , AT- 1 3 4 , "DTC
P1716 TURBINE REVOLUTION SENSOR" , AT- 1 2 9 , "DTC P1705 THROTTLE POSITION SEN-
SOR" , AT-103, "DTC U1000 CAN COMMUNICATION LINE" .
NO >> GO TO 2.
2. CHECK A/T FLUID LEVEL
Check A/T fluid level. Refer to AT- 1 3 , "
Checking A/T Fluid" .
OK or NG
OK >> GO TO 3.
NG >> Refill ATF.
SAT6 3 8A

TROUBLE DIAGNOSIS FOR SYMPTOMS
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7. DETECT MALFUNCTIONING ITEM

Check the malfunction items. If any items are damaged, repair or replace damaged parts. Refer to AT-68,
"Symptom Chart" (Symptom No.24).
OK or NG
OK >> GO TO 8.
NG >> Repair or replace damaged parts.
8. CHECK SYMPTOM
Check again. Refer to AT- 6 3 , "
Cruise Test - Part 1" .
OK or NG
OK >>INSPECTION END
NG >> GO TO 9.
9. PERFORM TCM INSPECTION
1. Perform TCM input/output signals inspection. Refer to AT-90, "
TCM Input/Output Signal Reference Val-
ues" .
2. If NG, recheck A/T assembly harness connector terminals for damage or loose connection with harness
connector.
OK or NG
OK >>INSPECTION END
NG >> Repair or replace damaged parts.
10. DETECT MALFUNCTIONING ITEM

Check the malfunction items. If any items are damaged, repair or replace damaged parts. Refer to AT-68,
"Symptom Chart" (Symptom No.24).
OK or NG
OK >> GO TO 8.
NG >> Repair or replace damaged parts.
A/T Does Not Hold Lock-up ConditionUCS002IV
SYMPTOM:
The lock-up condition cannot be maintained for more than 30 seconds.
DIAGNOSTIC PROCEDURE
1. CHECK SELF-DIAGNOSTIC RESULTS
Perform self-diagnosis. Refer to AT- 9 3 , "
SELF-DIAGNOSTIC RESULT MODE" .
Do the self-diagnostic results indicate torque converter clutch solenoid valve, engine speed signal, turbine rev-
olution sensor, CAN communication?
YES >> Check the malfunctioning system. Refer to AT- 11 8 , "DTC P0740 TORQUE CONVERTER
CLUTCH SOLENOID VALVE" , AT-115, "DTC P0725 ENGINE SPEED SIGNAL" , AT- 1 3 4 , "DTC
P1716 TURBINE REVOLUTION SENSOR" , AT-103, "DTC U1000 CAN COMMUNICATION
LINE" .
NO >> GO TO 2.

TROUBLE DIAGNOSIS FOR SYMPTOMS
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7. DETECT MALFUNCTIONING ITEM

Check the malfunction items. If any items are damaged, repair or replace damaged parts. Refer to AT-68,
"Symptom Chart" (Symptom No.25).
OK or NG
OK >> GO TO 5.
NG >> Repair or replace damaged parts.
Lock-up Is Not ReleasedUCS002IW
SYMPTOM:
The lock-up condition cannot be cancelled even after releasing the accelerator pedal.
DIAGNOSTIC PROCEDURE
1. CHECK SELF-DIAGNOSTIC RESULTS
Perform self-diagnosis. Refer to AT- 9 3 , "
SELF-DIAGNOSTIC RESULT MODE" .
Do the self-diagnostic results indicate torque converter clutch solenoid valve, engine speed signal, turbine rev-
olution sensor, CAN communication?
YES >> Check the malfunctioning system. Refer to AT- 11 8 , "DTC P0740 TORQUE CONVERTER
CLUTCH SOLENOID VALVE" , AT-115, "DTC P0725 ENGINE SPEED SIGNAL" , AT- 1 3 4 , "DTC
P1716 TURBINE REVOLUTION SENSOR" , AT-103, "DTC U1000 CAN COMMUNICATION
LINE" .
NO >> GO TO 2.
2. CHECK SYMPTOM
Check again. Refer to AT- 6 3 , "
Cruise Test - Part 1" .
OK or NG
OK >>INSPECTION END
NG >> GO TO 3.
3. PERFORM TCM INSPECTION
1. Perform TCM input/output signals inspection. Refer to AT-90, "
TCM Input/Output Signal Reference Val-
ues" .
2. If NG, recheck A/T assembly harness connector terminals for damage or loose connection with harness
connector.
OK or NG
OK >>INSPECTION END
NG >> Repair or replace damaged parts.

ATC-1
AUTOMATIC AIR CONDITIONER
J AIR CONDITIONER
CONTENTS
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SECTION AT C
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Revision: August 20072004 QX56 PRECAUTIONS .......................................................... 5
Precautions for Supplemental Restraint System
(SRS) “AIR BAG” and “SEAT BELT PRE-TEN-
SIONER” .................................................................. 5
Precautions for Working with HFC-134a (R-134a) ..... 5
Contaminated Refrigerant ........................................ 5
General Refrigerant Precautions .............................. 6
Precautions for Leak Detection Dye ......................... 6
A/C Identification Label ............................................ 7
Precautions for Refrigerant Connection ................... 7
FEATURES OF NEW TYPE REFRIGERANT
CONNECTION ...................................................... 7
O-RING AND REFRIGERANT CONNECTION ..... 8
Precautions for Servicing Compressor ....................11
Precautions for Service Equipment .........................11
RECOVERY/RECYCLING EQUIPMENT .............11
ELECTRONIC LEAK DETECTOR .......................11
VACUUM PUMP ................................................. 12
MANIFOLD GAUGE SET .................................... 12
SERVICE HOSES ............................................... 12
SERVICE COUPLERS ........................................ 13
REFRIGERANT WEIGHT SCALE ...................... 13
CHARGING CYLINDER ...................................... 13
Wiring Diagrams and Trouble Diagnosis ................ 13
PREPARATION ......................................................... 14
Special Service Tools ............................................. 14
HFC-134a (R-134a) Service Tools and Equipment ... 14
Commercial Service Tools ...................................... 17
REFRIGERATION SYSTEM ..................................... 18
Refrigerant Cycle ................................................... 18
REFRIGERANT FLOW ....................................... 18
Refrigerant System Protection ............................... 18
REFRIGERANT PRESSURE SENSOR ............. 18
PRESSURE RELIEF VALVE .............................. 19
Component Layout ................................................. 20
FRONT REFRIGERATION SYSTEM .................. 20
REAR REFRIGERATION SYSTEM .................... 21LUBRICANT .............................................................. 22
Maintenance of Lubricant Quantity in Compressor ... 22
LUBRICANT ........................................................ 22
CHECKING AND ADJUSTING ............................ 22
AIR CONDITIONER CONTROL ............................... 24
Description .............................................................. 24
Operation ................................................................ 24
AIR MIX DOORS CONTROL .............................. 24
FAN SPEED CONTROL ...................................... 24
INTAKE DOOR CONTROL ................................. 24
MODE DOOR CONTROL ................................... 24
DEFROSTER DOOR CONTROL ........................ 24
MAGNET CLUTCH CONTROL ........................... 25
SELF-DIAGNOSTIC SYSTEM ............................ 25
Description of Control System ................................ 26
Control Operation ................................................... 26
DISPLAY SCREEN .............................................. 27
AUTO SWITCH ................................................... 27
TEMPERATURE DIAL (DRIVER) ........................ 27
TEMPERATURE DIAL (PASSENGER) ............... 27
RECIRCULATION SWITCH () ............................. 27
DEFROSTER () SWITCH .................................... 27
REAR WINDOW DEFOGGER SWITCH ............. 27
OFF SWITCH (HOLD FAN DOWN SWITCH
UNTIL SYSTEM SHUTS OFF) ............................ 27
A/C SWITCH ....................................................... 27
MODE SWITCH .................................................. 27
FRONT FAN SWITCH ......................................... 27
REAR FAN SWITCH (FRONT) ............................ 27
REAR TEMPERATURE/MODE DIAL (FRONT) ... 27
REAR TEMPERATURE/MODE DIAL (REAR) .... 28
REAR FAN CONTROL SWITCH (REAR) ........... 28
Discharge Air Flow ................................................. 29
FRONT ................................................................ 29
REAR .................................................................. 29
System Description (Front) ..................................... 30
CONTROLS AND THEIR FUNCTIONS .............. 30
System Description (Rear) ..................................... 31
CONTROLS AND THEIR FUNCTIONS .............. 31
CAN Communication System Description .............. 32

AIR CONDITIONER CONTROL
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MAGNET CLUTCH CONTROL
When the A/C or DEF switch is activated, the front air control outputs a compressor ON signal to the BCM.
Upon receiving this input, the BCM sends a compressor ON signal to the ECM via CAN communication lines.
The ECM then judges whether the compressor can be turned ON, based on each sensor status (refrigerant
pressure sensor signal, throttle angle sensor, etc.). If it determines the compressor can be turned ON, a com-
pressor ON signal is sent to the IPDM E/R via CAN communication lines.
Upon receipt of a compressor ON signal, the IPDM E/R turns ON the A/C relay which engages the magnet
clutch and operates the A/C compressor.
SELF-DIAGNOSTIC SYSTEM
A self-diagnostic system is built into the front air control to quickly locate the cause of symptoms. Refer to
ATC-53, "
A/C System Self-diagnosis Function"
WJIA0751E

ATC-32
AIR CONDITIONER CONTROL
Revision: August 20072004 QX56
CAN Communication System DescriptionEJS002C3
Refer to LAN-5, "CAN COMMUNICATION" .

TROUBLE DIAGNOSIS
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TROUBLE DIAGNOSISPFP:00004
CONSULT-II Function (BCM)EJS002C4
CONSULT-II can display each diagnostic item using the diagnostic test modes shown following.
CONSULT-II BASIC OPERATION
CAUTION:
If CONSULT-II is used with no connection of CONSULT-II CONVERTER, malfunctions might be
detected in self-diagnosis depending on control unit which carries out CAN communication.
1. With the ignition switch OFF, connect CONSULT-II and CON-
SULT-II CONVERTER to the data link connector, then turn the
ignition switch ON.
2. Touch “START (NISSAN BASED VHCL)”.
3. Touch “BCM” on “SELECT SYSTEM” screen. If “BCM” is not
indicated, go to GI-39, "
CONSULT-II Data Link Connector (DLC)
Circuit" .
BCM diagnostic
test itemDiagnostic mode Description
Inspection by partWORK SUPPORTSupports inspections and adjustments. Commands are transmitted to the BCM
for setting the status suitable for required operation, input/output signals are
received from the BCM and received data is displayed.
DATA MONITOR Displays BCM input/output data in real time.
ACTIVE TEST Operation of electrical loads can be checked by sending drive signal to them.
SELF-DIAG RESULTS Displays BCM self-diagnosis results.
CAN DIAG SUPPORT MNTR The result of transmit/receive diagnosis of CAN communication can be read.
ECU PART NUMBER BCM part number can be read.
CONFIGURATION Performs BCM configuration read/write functions.
BBIA0369E
BCIA0029E
BCIA0030E