2004 INFINITI QX56 Engine Control System

-1QUICK REFERENCE INDEX AGENERAL INFORMATIONGIGeneral InformationBENGINEEMEngine MechanicalLUEngine Lubrication SystemCOEngine Cooling SystemECEngine Control SystemFLFuel SystemEXExhaust SystemACCAccelerator Control SystemCTRANSMISSION/
TRANSAXLEATAutomatic TransmissionDDRIVELINE/AXLETFTransferPRPropeller ShaftFFDFront Final DriveRFDRear Final DriveFAXFront AxleRAXRear AxleESUSPENSIONFSUFront SuspensionRSURear SuspensionWTRoad Wheels & TiresFBRAKESBRBrake SystemPBParking Brake SystemBRCBrake Control SystemGSTEERINGPSPower Steering SystemHRESTRAINTSSBSeat BeltsSRSSupplemental Restraint System (SRS)IBODYBLBody, Lock & Security SystemGWGlasses, Window System & MirrorsRFRoofEIExterior & InteriorIPInstrument PanelSESeatAPAdjustable PedalsJAIR CONDITIONERATCAutomatic Air ConditionerKELECTRICALSCStarting & Charging SystemLTLighting SystemDIDriver Information SystemWWWiper, Washer & HornBCSBody Control SystemLANLAN SystemAVAudio Visual, Navigation & Telephone SystemACSAuto Cruise Control SystemPGPower Supply, Ground & Circuit ElementsLMAINTENANCEMAMaintenanceMINDEXIDXAlphabetical IndexEdition: February 2004
Revision: August 2007BDACEFGHIJKLM

ACC-1
ACCELERATOR CONTROL SYSTEM
B ENGINE
CONTENTS
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SECTION ACC
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ACC
Revision: August 20072004 QX56 ACCELERATOR CONTROL SYSTEM ...................... 2
Removal and Installation .......................................... 2
REMOVAL ............................................................. 2
INSTALLATION ..................................................... 3
INSPECTION AFTER INSTALLATION ................. 3SERVICE DATA AND SPECIFICATIONS (SDS) ........ 4
Accelerator Control ................................................... 4
ADJUSTABLE ACCELERATOR PEDAL ............... 4

ACTION TEST
ACS-9
[ICC]
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Revision: August 20072004 QX56
ACTION TESTPFP:00000
ICC System Running TestEKS007YE
VEHICLE-TO-VEHICLE DISTANCE CONTROL MODE
SET CHECKING
1. Press the ON/OFF switch for less than 1.5 seconds.
2. Drive the vehicle between 25 MPH (40 km/h) and 89 MPH (144 km/h).
3. Push the COAST/SET switch.
4. Confirm that the desired speed is set as the COAST/SET switch is released.
NOTE:

When there is no vehicle ahead, drive at the set speed steadily.

When there is a vehicle ahead, control to maintain distance from the vehicle ahead, watching its speed.

The set vehicle speed is displayed on the ICC system indicator in the combination meter.
CHECK FOR INCREASE OF THE CRUISING SPEED
1. Set vehicle-to-vehicle distance control mode at desired speed.
2. Check if the set speed increases by 1 MPH (1 km/h) as ACCEL/RES switch is pushed.
NOTE:
The maximum set speed of the vehicle-to-vehicle distance control mode is 89 MPH (144 km/h).
CHECK FOR DECREASE OF THE CRUISING SPEED
1. Set vehicle-to-vehicle distance control mode at desired speed.
2. Check if the set speed decreases by 1 MPH (1 km/h) as COAST/SET switch is pushed.
NOTE:

Vehicle-to-vehicle distance control mode is automatically turned off when the driving speed lowers to 20
MPH (32 km/h) due to the deceleration of the vehicle ahead.

The minimum set speed of the vehicle-to-vehicle distance control mode is 25 MPH (40 km/h).
CHECK FOR THE CANCELLATION OF VEHICLE-TO-VEHICLE DISTANCE CONTROL MODE
(NORMAL DRIVING CONDITION) IN THE FOLLOWING CASES:
1. When the brake pedal is depressed after the system is turned on.
2. When the A/T select lever is shifted into gears other than “D”, including manual shifts.
3. When the system is turned off.
4. When CANCEL switch is operated.
CHECK FOR RESTORING THE SPEED THAT IS SET BY VEHICLE-TO-VEHICLE DISTANCE
CONTROL MODE BEFORE CANCELLATION
1. Cancel the system by depressing the brake. Then, check that the speed before cancellation is restored
when pressing ACCEL/RES switch with vehicle speed at 25 MPH (40 km/h) or above.
2. Cancel the system by shifting the select lever into other than “D”. Then, check if the speed set before the
cancellation is restored when ACCEL/RES switch is pressed.
3. Check if the speed previously set is restored when ACCEL/RES switch is operated when driving 25 MPH
(40 km/h) or above, after canceling vehicle-to-vehicle distance control mode by operating the CANCEL
switch.
CHECK ON/OFF SWITCH OPERATION
1. Start the engine. Then, check that the following operations are
performed correctly.
2. Vehicle-to-vehicle distance control mode is displayed when ON/
OFF switch is pressed ON. Vehicle-to-vehicle distance control
mode goes off when ON/OFF switch is turned to OFF.
3. Turn off the ignition switch while ON/OFF switch is ON. Turn the
ignition switch back to ON and confirm that CRUISE lamp and
ICC system display are OFF.
WKIA1978E

ACS-10
[ICC]
ACTION TEST
Revision: August 20072004 QX56
CHECK FOR ACCEL/RES, COAST/SET, CANCEL SWITCHES
1. Check if ACCEL/RES, COAST/SET, CANCEL switches operate smoothly.
2. Check if switch buttons rebound as the buttons are released.
CHECK FOR DISTANCE SWITCH
1. Start the engine.
2. Press the ON/OFF switch for less than 1.5 seconds.
3. Press the DISTANCE switch.
4. Check if the set distance indicator changes display in order of:
(long)→(middle)→(short).
NOTE:
The set distance indicator shows long immediately after the engine starts.
CONVENTIONAL (FIXED SPEED) CRUISE CONTROL MODE
SET CHECKING
1. Press the ON/OFF switch for more than 1.5 seconds.
2. Drive the vehicle between 25 MPH (40 km/h) and 89 MPH (144 km/h).
3. Push the COAST/SET switch.
4. Confirm that the desired speed is set when the COAST/SET switch is released.
NOTE:

ICC system display in the combination meter shows nothing.
SKIA6178E

ACTION TEST
ACS-11
[ICC]
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ACS
Revision: August 20072004 QX56
CHECK FOR INCREASE OF THE CRUISING SPEED
1. Set the conventional (fixed speed) cruise control mode at desired speed.
2. Check if the set speed increases by 1 MPH (1.6 km/h) as ACCEL/RES switch is pushed.
NOTE:

If the ACCEL/RES switch is held, the vehicle speed increases until the switch is released.

The maximum set speed is 89 MPH (144 km/h).
CHECK FOR DECREASE OF THE CRUISING SPEED
1. Set the conventional (fixed speed) cruise control mode at desired speed.
2. Check if the set speed decreases by 1 MPH (1.6 km/h) as COAST/SET switch is pushed.
NOTE:

Conventional (fixed speed) cruise control mode is automatically turned off when the driving speed lowers
to 20 MPH (32 km/h).

The lowest set speed is 25 MPH (40 km/h).
CHECK FOR THE CANCELLATION OF CONVENTIONAL (FIXED SPEED) CRUISE CONTROL
MODE (NORMAL DRIVING CONDITION) IN THE FOLLOWING CASES:
Refer to ACS-9, "CHECK FOR THE CANCELLATION OF VEHICLE-TO-VEHICLE DISTANCE CONTROL
MODE (NORMAL DRIVING CONDITION) IN THE FOLLOWING CASES:"
CHECK FOR RESTORING THE SPEED THAT IS SET BY CONVENTIONAL (FIXED SPEED)
CRUISE CONTROL MODE BEFORE ICC CANCELLATION
Refer to ACS-9, "CHECK FOR RESTORING THE SPEED THAT IS SET BY VEHICLE-TO-VEHICLE DIS-
TANCE CONTROL MODE BEFORE CANCELLATION"
CHECK ON/OFF SWITCH OPERATION
1. Start the engine. Then, check that the following operations are
performed correctly.
2. CRUISE lamp (green) illuminates and ICC system indicator
goes off when ON/OFF switch is pressed ON for more than 1.5
seconds. The CRUISE lamp goes off when ON/OFF switch is
turned to OFF.
3. Turn off the ignition switch while ON/OFF switch is ON. Turn the
ignition switch back to ON and confirm that CRUISE lamp is
OFF.
CHECK FOR ACCEL/RES, COAST/SET, CANCEL SWITCHES
1. Check if ACCEL/RES, COAST/SET, CANCEL switches operate smoothly.
2. Check if switch buttons rebound as the buttons are released.
WKIA2038E

AT-1
AUTOMATIC TRANSMISSION
C TRANSMISSION/TRANSAXLE
CONTENTS
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SECTION AT
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AT
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

A/T CONTROL SYSTEM
AT-23
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Revision: August 20072004 QX56
“D”, “4”, “3”, “2” Positions 1st Gear

The forward brake and the forward one-way clutch regulate reverse rotation of the mid sun gear.

The 1st one-way clutch regulates reverse rotation of the rear sun gear.

The 3rd one-way clutch regulates reverse rotation of the front sun gear.

During deceleration, the mid sun gear turns forward, so the forward one-way clutch idles and the engine
brake is not activated.
1. Front brake 2. Input clutch 3. Direct clutch
4. High and low reverse clutch 5. Reverse brake 6. Forward brake
7. Low coast brake 8. 1st one-way clutch 9. Forward one-way clutch
10. 3rd one-way clutch 11. Front sun gear 12. Input shaft
13. Mid internal gear 14. Front internal gear 15. Rear carrier
16. Rear sun gear 17. Mid sun gear 18. Front carrier
19. Mid carrier 20. Rear internal gear 21. Output shaft
22. Parking gear 23. Parking pawl
SCIA1512E