2004 INFINITI QX56 Engine Control System

TROUBLE DIAGNOSIS FOR SYMPTOMS
AT-195
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Revision: August 20072004 QX56
5. CHECK SYMPTOM
Check again. Refer to AT- 6 2 , "
Check at Idle" .
OK or NG
OK >>INSPECTION END
NG >> GO TO 6.
6. 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.
Large Shock (“N” to “D” Position)UCS002IM
SYMPTOM:
A noticeable shock occurs when the selector lever is shifted from the “N” to “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 A/T fluid temperature sensor, engine speed signal, accelerator pedal
position sensor, ATF pressure switch 1, front brake solenoid valve, CAN communication line?
YES >> Check the malfunctioning system. Refer to AT-131, "DTC P1710 A/T FLUID TEMPERATURE
SENSOR CIRCUIT" , AT-115, "DTC P0725 ENGINE SPEED SIGNAL" ., AT- 1 2 9 , "DTC P1705
THROTTLE POSITION SENSOR" , AT-175, "DTC P1841 ATF PRESSURE SWITCH 1" , AT-
151, "DTC P1757 FRONT BRAKE SOLENOID VALVE" , AT- 1 0 3 , "DTC U1000 CAN COMMUNI-
CATION LINE" .
NO >> GO TO 2.
2. ENGINE IDLE SPEED
Check the engine idle speed. Refer to EC-32, "
Idle Speed and Ignition Timing Check" .
OK or NG
OK >> GO TO 3.
NG >> Repair.
3. CHECK CONTROL CABLE
Check the control cable.

Refer to AT- 2 3 4 , "Checking of A/T Position" .
OK or NG
OK >> GO TO 4.
NG >> Adjust control cable. Refer to AT-234, "
Adjustment of A/
T Position" .
LCIA0324E

TROUBLE DIAGNOSIS FOR SYMPTOMS
AT-199
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Revision: August 20072004 QX56
5. DETECT MALFUNCTIONING ITEM
1. Disassemble A/T. Refer to AT- 2 7 3 , "
Disassembly" .
2. Check the following items:
–Reverse brake. Refer to AT-273, "Disassembly" .
OK or NG
OK >> GO TO 9.
NG >> Repair or replace damaged parts.
6. CHECK LINE PRESSURE
Check the line pressure with the engine idling. Refer to AT-59, "
LINE
PRESSURE TEST" .
OK or NG
OK >> GO TO 9.
NG - 1 >> Line pressure high. GO TO 7.
NG - 2 >> Line pressure low. GO TO 8.
7. DETECT MALFUNCTIONING ITEM
1. Check control valve with TCM. Refer to AT-241, "
Control Valve With TCM and A/T Fluid Temperature Sen-
sor 2" .
2. Disassemble A/T. Refer to AT- 2 7 3 , "
Disassembly" .
3. Check the following items:
–Oil pump assembly. Refer to AT-290, "Oil Pump" .
OK or NG
OK >> GO TO 9.
NG >> Repair or replace damaged parts.
8. DETECT MALFUNCTIONING ITEM
1. Check control valve with TCM. Refer to AT-241, "
Control Valve With TCM and A/T Fluid Temperature Sen-
sor 2" .
2. Disassemble A/T. Refer to AT- 2 7 3 , "
Disassembly" .
3. Check the following items:
–Oil pump assembly. Refer to AT-290, "Oil Pump" .
–Power train system. Refer to AT- 2 7 3 , "Disassembly" .
–Transmission case. Refer to AT - 2 7 3 , "Disassembly" .
OK or NG
OK >> GO TO 9.
NG >> Repair or replace damaged parts.
SAT4 9 4G

TROUBLE DIAGNOSIS FOR SYMPTOMS
AT-209
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Revision: August 20072004 QX56
4. CHECK LINE PRESSURE
Check line pressure at the engine stall point. Refer to AT-59, "
LINE
PRESSURE TEST" .
OK or NG
OK >> GO TO 7.
NG - 1 >> Line pressure high. GO TO 5.
NG - 2 >> Line pressure low. GO TO 6.
5. DETECT MALFUNCTIONING ITEM
1. Check control valve with TCM. Refer to AT-241, "
Control Valve With TCM and A/T Fluid Temperature Sen-
sor 2" .
2. Disassemble A/T. Refer to AT- 2 7 3 , "
Disassembly" .
3. Check the following items:
–Oil pump assembly. Refer to AT-290, "Oil Pump" .
OK or NG
OK >> GO TO 7.
NG >> Repair or replace damaged parts.
6. DETECT MALFUNCTIONING ITEM
1. Check control valve with TCM. Refer to AT-241, "
Control Valve With TCM and A/T Fluid Temperature Sen-
sor 2" .
2. Disassemble A/T. Refer to AT- 2 7 3 , "
Disassembly" .
3. Check the following items:
–Oil pump assembly. Refer to AT-290, "Oil Pump" .
–Power train system. Refer to AT- 2 7 3 , "Disassembly" .
–Transmission case. Refer to AT - 2 7 3 , "Disassembly" .
OK or NG
OK >> GO TO 7.
NG >> Repair or replace damaged parts.
7. CHECK A/T FLUID CONDITION
1. Remove oil pan. Refer to AT-241, "
Control Valve With TCM and A/T Fluid Temperature Sensor 2" .
2. Check A/T fluid condition. Refer to AT- 5 8 , "
Fluid Condition
Check" .
OK or NG
OK >> GO TO 8.
NG >> GO TO 11.
SAT4 9 4G
SCIA5199E

TROUBLE DIAGNOSIS FOR SYMPTOMS
AT-211
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Revision: August 20072004 QX56
P1705 THROTTLE POSITION SENSOR" , AT- 11 2 , "DTC P0720 VEHICLE SPEED SENSOR A/T
(REVOLUTION SENSOR)" , AT - 1 3 6 , "DTC P1721 VEHICLE SPEED SENSOR MTR" .
NO >> GO TO 3.
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 LINE PRESSURE
Check line pressure at the engine stall point. Refer to AT-59, "
LINE
PRESSURE TEST" .
OK or NG
OK >> GO TO 7.
NG - 1 >> Line pressure high. GO TO 5.
NG - 2 >> Line pressure low. GO TO 6.
5. DETECT MALFUNCTIONING ITEM
1. Check control valve with TCM. Refer to AT-241, "
Control Valve With TCM and A/T Fluid Temperature Sen-
sor 2" .
2. Disassemble A/T. Refer to AT- 2 7 3 , "
Disassembly" .
3. Check the following items:
–Oil pump assembly. Refer to AT-290, "Oil Pump" .
OK or NG
OK >> GO TO 7.
NG >> Repair or replace damaged parts.
6. DETECT MALFUNCTIONING ITEM
1. Check control valve with TCM. Refer to AT-241, "
Control Valve With TCM and A/T Fluid Temperature Sen-
sor 2" .
2. Disassemble A/T. Refer to AT- 2 7 3 , "
Disassembly" .
3. Check the following items:
–Oil pump assembly. Refer to AT-290, "Oil Pump" .
–Power train system. Refer to AT- 2 7 3 , "Disassembly" .
–Transmission case. Refer to AT - 2 7 3 , "Disassembly" .
OK or NG
OK >> GO TO 7.
NG >> Repair or replace damaged parts.
SAT6 3 8A
SAT4 9 4G

AT-216
TROUBLE DIAGNOSIS FOR SYMPTOMS
Revision: August 20072004 QX56
3. CHECK LINE PRESSURE
Check line pressure at the engine stall point. Refer to AT- 5 9 , "
LINE
PRESSURE TEST" .
OK or NG
OK >> GO TO 6.
NG - 1 >> Line pressure high. GO TO 4.
NG - 2 >> Line pressure low. GO TO 5.
4. DETECT MALFUNCTIONING ITEM
1. Check control valve with TCM. Refer to AT- 2 4 1 , "
Control Valve With TCM and A/T Fluid Temperature Sen-
sor 2" .
2. Disassemble A/T. Refer to AT-273, "
Disassembly" .
3. Check the following items:
–Oil pump assembly. Refer to AT-290, "Oil Pump" .
OK or NG
OK >> GO TO 7.
NG >> Repair or replace damaged parts.
5. DETECT MALFUNCTIONING ITEM
1. Check control valve with TCM. Refer to AT- 2 4 1 , "
Control Valve With TCM and A/T Fluid Temperature Sen-
sor 2" .
2. Disassemble A/T. Refer to AT-273, "
Disassembly" .
3. Check the following items:
–Oil pump assembly. Refer to AT-290, "Oil Pump" .
–Power train system. Refer to AT-273, "Disassembly" .
–Transmission case. Refer to AT-273, "Disassembly" .
OK or NG
OK >> GO TO 7.
NG >> Repair or replace damaged parts.
6. CHECK A/T FLUID CONDITION
1. Remove oil pan. Refer to AT-241, "
Control Valve With TCM and A/T Fluid Temperature Sensor 2" .
2. Check A/T fluid condition. Refer to AT- 5 8 , "
Fluid Condition
Check" .
OK or NG
OK >> GO TO 7.
NG >> GO TO 10.
SAT4 9 4G
SCIA5199E

AT-220
TROUBLE DIAGNOSIS FOR SYMPTOMS
Revision: August 20072004 QX56
Engine Speed Does Not Return to IdleUCS002IX
SYMPTOM:
When a shift-down is performed, the engine speed does not smoothly return to the idling speed.
DIAGNOSTIC PROCEDURE
1. CHECK A/T FLUID LEVEL
Check A/T fluid level. Refer to AT-13, "
Checking A/T Fluid" .
OK or NG
OK >> GO TO 2.
NG >> Refill ATF.
2. CHECK SELF-DIAGNOSTIC RESULTS
Perform self-diagnosis. Refer to AT- 9 3 , "
SELF-DIAGNOSTIC RESULT MODE" .
Do the self-diagnostic results indicate front brake solenoid valve, direct clutch solenoid valve, ATF pressure
switch 1, ATF pressure switch 5, accelerator pedal position sensor, vehicle speed sensor A/T (revolution sen-
sor) and vehicle speed sensor MTR?
YES >> Check the malfunctioning system. Refer to AT-151, "DTC P1757 FRONT BRAKE SOLENOID
VA LV E" , AT-157, "DTC P1762 DIRECT CLUTCH SOLENOID VALVE" , AT- 1 7 5 , "DTC P1841
ATF PRESSURE SWITCH 1" , AT-181, "DTC P1845 ATF PRESSURE SWITCH 5" , AT-129,
"DTC P1705 THROTTLE POSITION SENSOR" , AT- 11 2 , "DTC P0720 VEHICLE SPEED SEN-
SOR A/T (REVOLUTION SENSOR)" , AT-136, "DTC P1721 VEHICLE SPEED SENSOR MTR" .
NO >> GO TO 3.
3. CHECK A/T FLUID CONDITION
1. Remove oil pan. Refer to AT-241, "
Control Valve With TCM and A/T Fluid Temperature Sensor 2" .
2. Check A/T fluid condition. Refer to AT- 5 8 , "
Fluid Condition
Check" .
OK or NG
OK >> GO TO 4.
NG >> GO TO 7.
4. 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.65).
OK or NG
OK >> GO TO 5.
NG >> Repair or replace damaged parts.
SAT6 3 8A
SCIA5199E

AT-234
SHIFT CONTROL SYSTEM
Revision: August 20072004 QX56
REMOVAL
1. Remove the select lever knob.
2. Remove console finisher.

Refer to IP-10, "INSTRUMENT PANEL ASSEMBLY" .
3. Remove center console.

Refer to IP-10, "INSTRUMENT PANEL ASSEMBLY" .
4. Disconnect selector control cable.
5. Disconnect A/T device harness connector.
6. Remove control device assembly.
INSTALLATION
Installation is in reverse order of removal.
NOTE:


: Vehicle front
Apply adhesive, Cemedyne 3000 or equivalent, to thread of select
lever knob before installation. Rotate knob clockwise through com-
plete thread range (A) at low torque. When knob rotation is finished
through complete thread range, rotation torque will sunddenly
increase. Continue knob rotation in incomplete thread range (B), not
more than 360°, until knob rotational position is as shown.

After installation is completed, adjust and check A/T position.
Adjustment of A/T PositionECS0090O
1. Loosen nut of control cable.
2. Place PNP switch and selector lever in “P” position.
3. After pushing the control cable in the direction shown with a
force of 9.8 N·m (1kg-m, 2.2 lb-ft), release it. This is in the natu-
ral state, tighten control cable nut to specifications.
Checking of A/T PositionECS0090P
1. Place selector lever in “P” position, and turn ignition switch ON
(engine stop).
2. Make sure selector lever can be shifted to other than “P” posi-
tion when brake pedal is depressed. Also make sure selector
lever can be shifted from “P” position only when brake pedal is
depressed.
3. Move the selector lever and check for excessive effort, sticking,
noise or rattle.
4. Confirm the selector lever stops at each position with the feel of
engagement when it is moved through all the positions. Check
whether or not the actual position the selector lever is in
matches the position shown by the shift position indicator and
the transmission body.
5. The method of operating the lever to individual positions correctly should be as shown.
6. Confirm the back-up lamps illuminate only when lever is placed in the “R” position. Confirm the back-up
lamps does not illuminate when selector lever is pushed against “R” position in the “P” or “N” position.
LCIA0323E
LCIA0397E
Control cable nut : 14.5 N·m (1.5 kg-m, 11 ft-lb)
LCIA0345E
LCIA0325E

SHIFT CONTROL SYSTEM
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Revision: August 20072004 QX56
7. Confirm the engine can only be started with the selector lever in the “P” and “N” positions.
8. Make sure transmission is locked completely in “P” position.