2008 INFINITI QX56 brake fluid

A/T CONTROL SYSTEMTM-21
< FUNCTION DIAGNOSIS >
CEF
G H
I
J
K L
M A
B
TM
N
O P
CONTROL SYSTEM DIAGRAM
CAN CommunicationINFOID:0000000001603991
SYSTEM DESCRIPTION
CAN (Controller Area Network) is a serial communication line for real time application. It is an on-vehicle mul-
tiplex communication line with high data communication speed and excellent error detection ability. Many elec-
tronic control units are equipped onto a vehicle, and each control unit shares information and links with other
control units during operation (not independent). In CAN communication, control units are connected with 2
communication lines (CAN H line, CAN L line) allowing a high rate of information transmission with less wiring.
Each control unit transmits/receives data but selectively reads required data only. For details, refer to LAN-4,
"System Description".
SENSORS (or SIGNALS)
⇒TCM
⇒ACTUATORS
Transmission range switch
Accelerator pedal position sensor
Closed throttle position signal
Wide open throttle position signal
Engine speed signal
A/T fluid temperature sensor
Output speed sensor
Vehicle speed signal
Stop lamp switch signal
Input speed sensor
1st position switch signal
4th position switch signal
ATF pressure switch 2 signal
Tow mode switch signal Shift control
Line pressure control
Lock-up control
Engine brake control
Timing control
Fail-safe control
Self-diagnosis
CONSULT-III co
mmunication
line
Duet-EA control
CAN system Input clutch solenoid valve
Direct clutch solenoid valve
Front brake solenoid valve
High and low reverse clutch sole-
noid valve
Low coast brake solenoid valve
Torque converter clutch solenoid
valve
Line pressure solenoid valve
A/T CHECK indicator lamp
Starter relay
Back-up lamp relay
JSDIA1315GB
Revision: March 2010
2008 QX56

TM-22
< FUNCTION DIAGNOSIS >
A/T CONTROL SYSTEM
Input/Output Signal of TCM
INFOID:0000000001603992
*1: Spare for output speed sensor
*2: Spare for accelerator pedal position signal
*3: If these input and output signals are different, the TCM triggers the fail-safe function.
*4: CAN comm unications
Line Pressure ControlINFOID:0000000001603993
• When an input torque signal equivalent to the engine drive force is sent from the ECM to the TCM, the TCM
controls the line pressure solenoid.
Control item Line
pressure control Ve h i c l e
speed
control Shift
control Lock-up
control Engine
brake
control Fail-safe
function (*3) Self-diag-
nostics
function
Input Accelerator pedal position signal
(*4)XXXXXXX
Output speed sensor A/T X X X X X X
Output speed sensor MTR
(*1) (*4)XXXX X
Closed throttle position signal
(*4)(*2) X (*2) X X (*2) XX
Wide open throttle position signal
(*4)(*2) X (*2) X (*2) XX
Input speed sensor 1 X XXX X
Input speed sensor 2
(for 4th speed only) X
XXX X
Engine speed signals
(*4)XX
Transmission range switch XXXXXXX
A/T fluid temperature sensors 1, 2 X X X X X X X
ASCD Operation signal
(*4)XXXX
Overdrive cancel sig-
nal
(*4)XX X
TCM power supply voltage signal X X X X X X
Out-
put Direct clutch solenoid
X XX X
Input clutch solenoid X XX X
High and low reverse clutch sole-
noid XX
XX
Front brake solenoid X XX X
Low coast brake solenoid (ATF
pressure switch 2) XX
XXX
Line pressure solenoid XXXXXXX
TCC solenoid XX X
Starter relay XX
Revision: March 2010 2008 QX56

TM-24
< FUNCTION DIAGNOSIS >
A/T CONTROL SYSTEM
The necessary and adequate line pressure for shift change is set.
For this reason, line pressure pattern setting corresponds to input
torque and gearshift selection. Also, line pressure characteristic is
set according to engine speed, during engine brake operation.
At Low Fluid Temperature
When the A/T fluid temperature drops below the prescribed tempera-
ture, in order to speed up the action of each friction element, the line
pressure is set higher than the normal line pressure characteristic.
Shift ControlINFOID:0000000001603994
The clutch pressure control solenoid is controlled by the signals from the switches and sensors. Thus, the
clutch pressure is adjusted to be appropriate to the engine load state and vehicle driving state. It becomes
possible to finely control the clutch hydraulic pressure with high precision and a smoother shift change charac-
teristic is attained.
SHIFT CHANGE
The clutch is controlled with the optimum timing and oil pressure by the engine speed, engine torque informa-
tion, etc.
Shift Change System Diagram
PCIA0010E
PCIA0011E
PCIA0012E
Revision: March 2010 2008 QX56

DIAGNOSIS SYSTEM (TCM)TM-33
< FUNCTION DIAGNOSIS >
CEF
G H
I
J
K L
M A
B
TM
N
O P
2GR INCORRECT RA-
TIO • A/T cannot shift to 2nd gear
P0732 P0732TM-56
3GR INCORRECT RA-
TIO• A/T cannot shift to 3rd gear
P0733 P0733TM-58
4GR INCORRECT RA-
TIO• A/T cannot shift to 4th gear
P0734 P0734TM-60
5GR INCORRECT RA-
TIO• A/T cannot shift to 5th gear
P0735 P0735TM-62
TORQUE CONVERT-
ER• Normal voltage not applied to solenoid due to cut line,
short, or the like P0740 P0740
TM-63
TORQUE CONVERT-
ER• A/T cannot perform lock-up even if electrical circuit is
good.
• TCM detects as irregular by comparing difference val- ue with slip rotation. P0744 P0744*2
TM-66
PC SOLENOID A• Normal voltage not applied to solenoid due to cut line,
short, or the like
• TCM detects as irregular by comparing target value with monitor value. P0745 P0745
TM-67
TP SENSOR• TCM does not receive the proper accelerator pedal po-
sition signals (input by CAN communication) from
ECM. P1705 P1705
TM-69
TRANS FLUID TEMP
SEN• During running, the ATF temperature sensor signal
voltage is excessively high or low P1710 P0710
TM-71
VEHICLE SPEED SIG-
NAL• Signal (CAN communication) from vehicle speed sen-
sor MTR not input due to cut line or the like
• Unexpected signal input during running P1721
—TM-74
INTERLOCK • Except during shift change, the gear position and ATF
pressure switch states are monitored and comparative
judgement made. P1730 P1730
TM-76
1ST E/BRAKING• Each ATF pressure switch and solenoid current is
monitored and if a pattern is detected having engine
braking 1st gear other than in the "1" position, a mal-
function is detected. P1731
—TM-78
INPUT CLUTCH SOLE-
NOID • Normal voltage not applied to solenoid due to function-
al malfunction, cut line, short, or the like
• TCM detects as irregular by comparing target value with monitor value. P1752 P1752
TM-80
FR BRAKE SOLENOID• Normal voltage not applied to solenoid due to function-
al malfunction, cut line, short, or the like
• TCM detects as irregular by comparing target value with monitor value. P1757 P1757
TM-82
DRCT CLUTCH SOLE-
NOID• Normal voltage not applied to solenoid due to cut line,
short, or the like
• TCM detects as irregular by comparing target value with monitor value. P1762 P1762
TM-84
HLR CLUTCH SOLE-
NOID• Normal voltage not applied to solenoid due to function-
al malfunction, cut line, short, or the like
• TCM detects as irregular by comparing target value with monitor value. P1767 P1767
TM-86
L C BRAKE SOLENOID• Normal voltage not applied to solenoid due to function-
al malfunction, cut line, short, or the like P1772 P1772
TM-88
Items (CONSULT-III
screen terms) Malfunction is detected when... TCM self-di-
agnosis OBD-II (DTC)
Reference page
“TRANSMIS-
SION” with
CONSULT-III MIL indicator
lamp*1, “EN-
GINE” with
CONSULT-III or
GST
Revision: March 2010 2008 QX56

P1731 1ST ENGINE BRAKINGTM-79
< COMPONENT DIAGNOSIS >
CEF
G H
I
J
K L
M A
B
TM
N
O P
OK or NG
OK >> GO TO 4.
NG >> GO TO 2.
2.CHECK TCM POWER SUPPLY AND GROUND CIRCUIT
Check TCM power supply and ground circuit. Refer to TM-92, "
Diagnosis Procedure".
OK or NG
OK >> GO TO 3.
NG >> Repair or replace damaged parts.
3.DETECT MALFUNCTIONING ITEM
Check the following items:
• The A/T assembly harness connector pin terminals for damage or loose connection with harness connector.
OK or NG
OK >> Replace the control valve with TCM. Refer to TM-201, "Control Valve with TCM and A/T Fluid
Temperature Sensor 2".
NG >> Repair or replace damaged parts.
4.CHECK DTC
Perform “DTC Confirmation Procedure”.
• Refer to TM-78, "
DTC Confirmation Procedure".
OK or NG
OK >> INSPECTION END
NG >> GO TO 2.
ATF PRES
SW 2 Low coast brake engaged. Refer to
TM-9.ON
Low coast brake disengaged. Refer to TM-9
.OFF
Item name
Condition Display value
Revision: March 2010 2008 QX56

P1757 FRONT BRAKE SOLENOIDTM-83
< COMPONENT DIAGNOSIS >
CEF
G H
I
J
K L
M A
B
TM
N
O P
OK or NG
OK >> GO TO 4.
NG >> GO TO 2.
2.CHECK TCM POWER SUPPLY AND GROUND CIRCUIT
Check TCM power supply and ground circuit. Refer to TM-92, "
Diagnosis Procedure".
OK or NG
OK >> GO TO 3.
NG >> Repair or replace damaged parts.
3.DETECT MALFUNCTIONING ITEM
Check the following items:
• The A/T assembly harness connector pin terminals for damage or loose connection with harness connector.
OK or NG
OK >> Replace the control valve with TCM. Refer to TM-201, "Control Valve with TCM and A/T Fluid
Temperature Sensor 2".
NG >> Repair or replace damaged parts.
4.CHECK DTC
Perform “DTC Confirmation Procedure”.
• Refer to TM-82, "
DTC Confirmation Procedure".
OK or NG
OK >> INSPECTION END
NG >> GO TO 2.
Item name Condition Display value (Ap-
prox.)
FR/B SOLE-
NOID Front brake engaged. Refer to
TM-9
0.6 - 0.8 A
Front brake disengaged. Refer to TM-9
0 - 0.05 A
Revision: March 2010 2008 QX56

P1772 LOW COAST BRAKE SOLENOIDTM-89
< COMPONENT DIAGNOSIS >
CEF
G H
I
J
K L
M A
B
TM
N
O P
NG >> GO TO 2.
2.CHECK TCM POWER SUPPLY AND GROUND CIRCUIT
Check TCM power supply and ground circuit. Refer to TM-92, "
Diagnosis Procedure".
OK or NG
OK >> GO TO 3.
NG >> Repair or replace damaged parts.
3.DETECT MALFUNCTIONING ITEM
Check the following items:
• The A/T assembly harness connector pin terminals for damage or loose connection with harness connector.
OK or NG
OK >> Replace the control valve with TCM. Refer to TM-201, "Control Valve with TCM and A/T Fluid
Temperature Sensor 2".
NG >> Repair or replace damaged parts.
4.CHECK DTC
Perform “DTC Confirmation Procedure”.
• Refer to TM-88, "
DTC Confirmation Procedure".
OK or NG
OK >> INSPECTION END
NG >> GO TO 2.
Revision: March 2010 2008 QX56

P1774 LOW COAST BRAKE SOLENOIDTM-91
< COMPONENT DIAGNOSIS >
CEF
G H
I
J
K L
M A
B
TM
N
O P
With CONSULT-III
1. Start the engine.
2. Select “SELECTION FROM MENU” in “DATA MONI TOR” mode for “TRANSMISSION” with CONSULT-III.
3. Drive vehicle in the “1” or “2” position (“1
1” or “22” gear) and confirm the ON/OFF actuation of the “ATF
PRES SW 2” and “ON OFF SOL”.
OK or NG
OK >> GO TO 4.
NG >> GO TO 2.
2.CHECK TCM POWER SUPPLY AND GROUND CIRCUIT
Check TCM power supply and ground circuit. Refer to TM-92, "
Diagnosis Procedure".
OK or NG
OK >> GO TO 3.
NG >> Repair or replace damaged parts.
3.DETECT MALFUNCTIONING ITEM
Check the following items:
• The A/T assembly harness connector pin terminals for damage or loose connection with harness connector.
OK or NG
OK >> Replace the control valve with TCM. Refer to TM-201, "Control Valve with TCM and A/T Fluid
Temperature Sensor 2".
NG >> Repair or replace damaged parts.
4.CHECK DTC
Perform “DTC Confirmation Procedure”.
• Refer to TM-90, "
DTC Confirmation Procedure".
OK or NG
OK >> INSPECTION END
NG >> GO TO 2.
Item name Condition Display value
ON OFF SOL Low coast brake engaged. Refer to
TM-9
ON
Low coast brake disengaged. Refer to TM-9
OFF
ATF PRES
SW 2 Low coast brake engaged. Refer to
TM-9
ON
Low coast brake disengaged. Refer to TM-9
OFF
Revision: March 2010 2008 QX56