2004 INFINITI QX56 diagram

ACS-24
[ICC]
WIRING DIAGRAM
Revision: August 20072004 QX56
WKWA3127E

AT-1
AUTOMATIC TRANSMISSION
C TRANSMISSION/TRANSAXLE
CONTENTS
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Revision: August 20072004 QX56 INDEX FOR DTC ........................................................ 5
Alphabetical Index .................................................... 5
DTC No. Index ......................................................... 6
PRECAUTIONS .......................................................... 7
Precautions for Supplemental Restraint System
(SRS) “AIR BAG” and “SEAT BELT PRE-TEN-
SIONER” .................................................................. 7
Precautions for On Board Diagnostic (OBD) System
of A/T and Engine .................................................... 7
Precautions .............................................................. 8
Service Notice or Precautions .................................. 9
Wiring Diagrams and Trouble Diagnosis .................. 9
PREPARATION ......................................................... 10
Special Service Tools ............................................. 10
Commercial Service Tools ...................................... 12
A/T FLUID ................................................................. 13
Changing A/T Fluid ................................................ 13
Checking A/T Fluid ................................................. 13
A/T Fluid Cooler Cleaning ...................................... 15
A/T CONTROL SYSTEM .......................................... 18
Cross-Sectional View (2WD models) ..................... 18
Cross-Sectional View (4WD models) ..................... 19
Shift Mechanism ..................................................... 20
TCM Function ......................................................... 31
CAN Communication .............................................. 32
Input/Output Signal of TCM .................................... 32
Line Pressure Control ............................................ 33
Shift Control ........................................................... 34
Lock-up Control ...................................................... 35
Engine Brake Control ............................................. 37
Control Valve .......................................................... 37
ON BOARD DIAGNOSTIC (OBD) SYSTEM ............ 39
Introduction ............................................................ 39
OBD-II Function for A/T System ............................. 39
One or Two Trip Detection Logic of OBD-II ............ 39
OBD-II Diagnostic Trouble Code (DTC) ................. 39
Malfunction Indicator Lamp (MIL) ........................... 42
TROUBLE DIAGNOSIS ............................................ 43
DTC Inspection Priority Chart ................................ 43
Fail-Safe ................................................................. 43How To Perform Trouble Diagnosis For Quick and
Accurate Repair ...................................................... 45
A/T Electrical Parts Location .................................. 50
Circuit Diagram ....................................................... 51
Wiring Diagram — AT — ........................................ 52
Inspections Before Trouble Diagnosis .................... 58
Check Before Engine is Started .............................. 62
Check at Idle ........................................................... 62
Cruise Test - Part 1 ................................................. 63
Cruise Test - Part 2 ................................................. 65
Cruise Test - Part 3 ................................................. 66
Vehicle Speed When Shifting Gears ...................... 67
Vehicle Speed When Performing and Releasing
Complete Lock-up .................................................. 67
Vehicle Speed When Performing and Releasing
Slip Lock-up ............................................................ 67
Symptom Chart ....................................................... 68
TCM Input/Output Signal Reference Values ........... 90
CONSULT-II Function (A/T) .................................... 91
DTC U1000 CAN COMMUNICATION LINE ............103
Description ............................................................103
On Board Diagnosis Logic ....................................103
Possible Cause .....................................................103
DTC Confirmation Procedure ...............................103
Diagnostic Procedure ...........................................104
DTC P0615 START SIGNAL CIRCUIT ...................105
Description ............................................................105
CONSULT-II Reference Value ..............................105
On Board Diagnosis Logic ....................................105
Possible Cause .....................................................105
DTC Confirmation Procedure ...............................105
Diagnostic Procedure ...........................................106
DTC P0700 TCM .....................................................108
Description ............................................................108
On Board Diagnosis Logic ....................................108
Possible Cause .....................................................108
DTC Confirmation Procedure ...............................108
Diagnostic Procedure ...........................................108
DTC P0705 PARK/NEUTRAL POSITION SWITCH .109
Description ............................................................109

AT-4Revision: August 20072004 QX56 A/T Does Not Shift: 2nd gear → 1st gear .............227
Vehicle Does Not Decelerate By Engine Brake ....230
SHIFT CONTROL SYSTEM ....................................233
Control Device Removal and Installation ..............233
Adjustment of A/T Position ...................................234
Checking of A/T Position ......................................234
A/T SHIFT LOCK SYSTEM .....................................236
Description ............................................................236
Shift Lock System Electrical Parts Location .........236
Wiring Diagram — A/T — SHIFT ..........................237
Shift Lock Control Unit Reference Values .............238
Component Inspection ..........................................239
ON-VEHICLE SERVICE ..........................................241
Control Valve With TCM and A/T Fluid Temperature
Sensor 2 ...............................................................241
Rear Oil Seal ........................................................252
AIR BREATHER HOSE ...........................................253
Removal and Installation ......................................253
TRANSMISSION ASSEMBLY ................................255
Removal and Installation (4x2) .............................255
Removal and Installation (4x4) .............................258
OVERHAUL .............................................................261
Components .........................................................261
Oil Channel ...........................................................269
Locations of Adjusting Shims, Needle Bearings,
Thrust Washers and Snap Rings ..........................271
DISASSEMBLY .......................................................273
Disassembly .........................................................273REPAIR FOR COMPONENT PARTS ...................... 290
Oil Pump ............................................................... 290
Front Sun Gear, 3rd One-Way Clutch ................... 292
Front Carrier, Input Clutch, Rear Internal Gear ..... 295
Mid Sun Gear, Rear Sun Gear, High and Low
Reverse Clutch Hub .............................................. 300
High and Low Reverse Clutch .............................. 305
Direct Clutch ......................................................... 307
ASSEMBLY ............................................................. 309
Assembly (1) ......................................................... 309
Adjustment ............................................................ 322
Assembly (2) ......................................................... 324
SERVICE DATA AND SPECIFICATIONS (SDS) .... 331
General Specifications .......................................... 331
Vehicle Speed When Shifting Gears ..................... 331
Vehicle Speed When Performing and Releasing
Complete Lock-up ................................................. 332
Vehicle Speed When Performing and Releasing
Slip Lock-up .......................................................... 332
Stall Speed ............................................................ 332
Line Pressure ........................................................ 332
A/T Fluid Temperature Sensor .............................. 332
Turbine Revolution Sensor .................................... 332
Vehicle Speed Sensor A/T (Revolution Sensor) ... 332
Reverse brake ....................................................... 333
Total End Play ....................................................... 333

PRECAUTIONS
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Revision: August 20072004 QX56
Service Notice or PrecautionsUCS002C4
ATF COOLER SERVICE
If A/T fluid contains frictional material (clutches, bands, etc.), or if an A/T is repaired, overhauled, or replaced,
inspect and clean the A/T fluid cooler mounted in the radiator or replace the radiator. Flush cooler lines using
cleaning solvent and compressed air after repair. For A/T fluid cooler cleaning procedure, refer to AT-15, "
A/T
Fluid Cooler Cleaning" . For radiator replacement, refer to CO-10, "RADIATOR" .
CHECKING AND CHANGING A/T FLUID SERVICE
Increase ATF temperature by 80°C (176°F) once, and then check ATF level in 65°C (149°F) when adjusting
ATF level.
NOTE:
JA60 uses both systems of a water-cooling and of an air-cooling. Air-cooling system has a by-pass valve.
When ATF temperature is not over 50°C (122°F) with water-cooling system OFF, it does not flow to air-cooling
system. If ATF level is set without the flow of ATF, the level will be 10mm lower than the standard. Therefore,
piping should be filled with ATF when adjusting level.
OBD-II SELF-DIAGNOSIS

A/T self-diagnosis is performed by the TCM in combination with the ECM. The results can be read through
the blinking pattern of the malfunction indicator lamp (MIL). Refer to the table on AT - 9 3 , "
SELF-DIAGNOS-
TIC RESULT MODE" for the indicator used to display each self-diagnostic result.

The self-diagnostic results indicated by the MIL are automatically stored in both the ECM and TCM mem-
ories.
Always perform the procedure on AT-40, "
HOW TO ERASE DTC" to complete the repair and avoid
unnecessary blinking of the MIL.
For details of OBD-II, refer to AT-39, "
ON BOARD DIAGNOSTIC (OBD) SYSTEM" .

Certain systems and components, especially those related to OBD, may use the new style slide-
locking type harness connector. For description and how to disconnect, refer to PG-68, "
HAR-
NESS CONNECTOR" .
Wiring Diagrams and Trouble DiagnosisUCS002C5
When you read wiring diagrams, refer to the following:

GI-15, "How to Read Wiring Diagrams".

PG-4, "POWER SUPPLY ROUTING CIRCUIT" for power distribution circuit.
When you perform trouble diagnosis, refer to the following:

GI-11, "How to Follow Trouble Diagnoses".

GI-27, "How to Perform Efficient Diagnosis for an Electrical Incident".

A/T CONTROL SYSTEM
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Revision: August 20072004 QX56
TCM FunctionUCS002CE
The function of the TCM is to:

Receive input signals sent from various switches and sensors.

Determine required line pressure, shifting point, lock-up operation, and engine brake operation.

Send required output signals to the respective solenoids.
CONTROL SYSTEM OUTLINE
The automatic transmission senses vehicle operating conditions through various sensors or signals. It always
controls the optimum shift position and reduces shifting and lock-up shocks.
CONTROL SYSTEM DIAGRAM
SENSORS (or SIGNALS)


TCM


ACTUATORS
PNP switch
Accelerator pedal position sensor
Closed throttle position signal
Wide open throttle position signal
Engine speed signal
A/T fluid temperature sensor
Revolution sensor
Vehicle speed signal
Stop lamp switch signal
Turbine revolution sensor
1st position switch signal
4th position switch signalShift control
Line pressure control
Lock-up control
Engine brake control
Timing control
Fail-safe control
Self-diagnosis
CONSULT-II communication line
Duet-EA control
CAN systemInput clutch solenoid valve
Direct clutch solenoid valve
Front brake solenoid valve
High and low reverse clutch
solenoid valve
Low coast brake solenoid valve
Torque converter clutch solenoid
valve
Line pressure solenoid valve
A/T CHECK indicator lamp
Sta rte r re lay
Back-up lamp relay
LCIA0317E

A/T CONTROL SYSTEM
AT-35
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Revision: August 20072004 QX56
Shift Change System Diagram
*1: Full phase real-time feedback control monitors movement of gear ratio at gear change, and controls oil
pressure at real-time to achieve the best gear ratio.
Lock-up ControlUCS002CJ
The torque converter clutch piston in the torque converter is engaged to eliminate torque converter slip to
increase power transmission efficiency.
The torque converter clutch control valve operation is controlled by the torque converter clutch solenoid valve,
which is controlled by a signal from TCM, and the torque converter clutch control valve engages or releases
the torque converter clutch piston.
Lock-up Operation Condition Table
TORQUE CONVERTER CLUTCH CONTROL VALVE CONTROL
Lock-up Control System Diagram
Lock-up Released

In the lock-up released state, the torque converter clutch control valve is set into the unlocked state by the
torque converter clutch solenoid and the lock-up apply pressure is drained.
In this way, the torque converter clutch piston is not coupled.
PCIA0013E
Select lever D position 4 position 3 position 2 position
Gear position 5 4 4 3 2
Lock-up×–×××
Slip lock-up××–––
PCIA0014E

TROUBLE DIAGNOSIS
AT-51
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Revision: August 20072004 QX56
Circuit DiagramUCS002CV
WCWA0216E

AT-52
TROUBLE DIAGNOSIS
Revision: August 20072004 QX56
Wiring Diagram — AT —UCS002CW
BCWA0157E