brake sensor INFINITI QX56 2008 Factory Owners Manual

TM-20
< FUNCTION DIAGNOSIS >
A/T CONTROL SYSTEM
TCM Function
INFOID:0000000001603990
The function of the TCM is to:
• Receive input signals sent from various switches and sensors.
• Determine required line pressure, shifting poi nt, 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 vari ous sensors or signals. It always
controls the optimum shift position and reduces shifting and lock-up shocks.
1. Front brake 2. Input clutch3. 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 gear12. Input shaft
13. Mid internal gear 14. Front internal gear15. Rear carrier
16. Rear sun gear 17. Mid sun gear18. Front carrier
19. Mid carrier 20. Rear internal gear21. Output shaft
22. Parking gear 23. Parking pawl
SCIA1519E
Revision: March 2010 2008 QX56

A/T CONTROL SYSTEMTM-21
< FUNCTION DIAGNOSIS >
CEF
G H
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K L
M A
B
TM
N
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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
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K L
M A
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TM
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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

TM-34
< FUNCTION DIAGNOSIS >
DIAGNOSIS SYSTEM (TCM)
*1: Refer to EC-55, "Malfunction Indicator Lamp (MIL)".
*2:These malfunctions cannot be displayed MIL if another malfunction is assigned to MIL.
DATA MONITOR MODE
Display Items List
X: Standard, —: Not applicable
LC/B SOLENOID FNCT • TCM detects an improper voltage drop when it tries to
operate the solenoid valve.
• Condition of ATF pressure switch 2 is different from
monitor value, and relation between gear position and
actual gear ratio is irregular. P1774 P1774*2
TM-90
NO DTC IS DETECTED
FURTHER TESTING
MAY BE REQUIRED• No NG item has been detected.
XX
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
Monitored item (Unit) Monitor Item Selection
Remarks
ECU IN-
PUT SIG-
NALS MAIN SIG-
NALS SELEC-
TION
FROM
MENU
VHCL/S SE·A/T (km/h) XXX Output speed sensor
VHCL/S SE·MTR (km/h) X— X
ACCELE POSI (0.0/8) X— X Accelerator pedal position signal
THROTTLE POSI (0.0/8) XXXDegree of opening for accelerator recognized by
the TCM
For fail-safe operation, the specific value used
for control is displayed.
CLSD THL POS (ON-OFF display) X— X
Signal input with CAN communications
W/O THL POS (ON-OFF display) X— X
BRAKE SW (ON-OFF display) X— X Stop lamp switch
GEAR —XXGear position recognized by the TCM updated
after gear-shifting
ENGINE SPEED (rpm) XXX
INPUT SPEED (rpm) XXX
OUTPUT REV (rpm) XXX
GEAR RATIO —XX
TC SLIP SPEED (rpm) —XXDifference between engine speed and torque
converter input shaft speed
F SUN GR REV (rpm) —— X
F CARR GR REV (rpm) —— X
ATF TEMP SE 1 (V) X— X
ATF TEMP SE 2 (V) X— X
ATF TEMP 1 (° C) —XX
ATF TEMP 2 (° C) —XX
BATTERY VOLT (V) X— X
ATF PRES SW 1 (ON-OFF display) XXX Not mounted but displayed.
Revision: March 2010 2008 QX56

TM-76
< COMPONENT DIAGNOSIS >
P1730 INTERLOCK
P1730 INTERLOCK
DescriptionINFOID:0000000001604112
• Fail-safe function to detect interlock conditions.
On Board Diagnosis LogicINFOID:0000000001604113
• This is an OBD-II self-diagnostic item.
• Diagnostic trouble code “P1730” with CONSULT-III is detected when TCM does not receive the proper volt-
age signal from the sensor and switch.
• TCM monitors and compares gear position and conditions of each ATF pressure switch when gear is steady.
Possible CauseINFOID:0000000001604114
• Harness or connectors (The solenoid and switch circuit is open or shorted.)
• Low coast brake solenoid valve
• ATF pressure switch 2
DTC Confirmation ProcedureINFOID:0000000001604115
NOTE:
If “DTC Confirmation Procedure” has been previously performed, always turn ignition switch “OFF”
and wait at least 10 seconds before performing the next test.
After the repair, perform the following proc edure to confirm the malfunction is eliminated.
WITH CONSULT-III
1. Turn ignition switch “ON”. (Do not start engine.)
2. Select “DATA MONITOR” mode for “TRANSMISSION” with CONSULT-III.
3. Start engine.
4. Drive vehicle and maintain the following conditions for at least 2 consecutive seconds. Selector lever: “D” position
5. If DTC is detected, go to TM-5, "
Work Flow".
WITH GST
Follow the procedure “With CONSULT-III”.
Judgement of InterlockINFOID:0000000001604116
• When Interlock is judged to be malfunctioning, the vehi cle should be fixed in 2GR, and should be set in a
condition in which it can travel.
NOTE:
When the vehicle is driven fixed in 2GR, a input speed sensor malfunction is displayed, but this is not a input
speed sensor malfunction.
• When interlock is detected at the 3GR or more, it is locked at the 2GR.
Diagnosis ProcedureINFOID:0000000001604117
1.SELF-DIAGNOSIS
With CONSULT-III
1. Drive vehicle.
2. Stop vehicle and turn ignition switch “OFF”.
3. Turn ignition switch “ON”.
4. Select “SELF-DIAG RESULTS” mode fo r “TRANSMISSION” with CONSULT-III.
OK or NG
OK >> GO TO 2.
NG >> Check low coast brake solenoid valve circuit and function. Refer to TM-88, "
Diagnosis Proce-
dure", TM-90, "Diagnosis Procedure".
2.CHECK DTC
Perform “DTC Confirmation Procedure”.
Revision: March 2010 2008 QX56

TM-78
< COMPONENT DIAGNOSIS >
P1731 1ST ENGINE BRAKING
P1731 1ST ENGINE BRAKING
DescriptionINFOID:0000000001604118
Fail-safe function to prevent sudden decrease in speed by engine brake other than at "1" position.
CONSULT-III Reference Value in Data Monitor ModeINFOID:0000000001604119
On Board Diagnosis LogicINFOID:0000000001604120
• This is not an OBD-II self-diagnostic item.
• Diagnostic trouble code “P1731” with CONSULT-III is detected under the following conditions.
- When TCM does not receive the proper voltage signal from the sensor.
- When TCM monitors ATF pressure switch 2 and solenoid monitor value, and detects as irregular when engine brake of 1st gear acts other than at 1 position.
Possible CauseINFOID:0000000001604121
• Harness or connectors(The sensor circuit is open or shorted.)
• Low coast brake solenoid valve
• ATF pressure switch 2
DTC Confirmation ProcedureINFOID:0000000001604122
NOTE:
If “DTC Confirmation Procedure” has been previously preformed, always turn ignition switch “OFF”
and wait at least 10 seconds before performing the next test.
After the repair, perform the following proc edure to confirm the malfunction is eliminated.
WITH CONSULT-III
1. Turn ignition switch “ON”. (Do not start engine.)
2. Select “DATA MONITOR” mode for “TRANSMISSION” with CONSULT-III.
3. Start engine.
4. Drive vehicle and maintain the following conditions for at least 2 consecutive seconds. ENGINE SPEED: 1,200 rpm
Selector lever: “1” position
Gear position: 1st gear
5. If DTC is detected, go to TM-78, "
Diagnosis Procedure".
Diagnosis ProcedureINFOID:0000000001604123
1.CHECK INPUT SIGNALS
With CONSULT-III
1. Start the engine.
2. Select “SELECTION FROM MENU” in “DATA MONITOR” for "TRANSMISSION" with CONSULT-III"
3. Drive vehicle in the “1” position (1st gear), and c onfirm the ON/OFF actuation of “ATF PRES SW 2” and
"ON OFF SOL".
Item name Condition Display value
ON OFF SOL Low coast brake engaged. Refer to
TM-9
.O N
Low coast brake disengaged. Refer to TM-9
.O FF
ATF PRES SW 2 Low coast brake engaged. Refer to
TM-9
ON
Low coast brake disengaged. Refer to TM-9
.O FF
Item name Condition Display value
ON OFF
SOL Low coast brake engaged. Refer to TM-9
.O
N
Low coast brake disengaged. Refer to TM-9
.OFF
Revision: March 2010 2008 QX56

P1731 1ST ENGINE BRAKINGTM-79
< COMPONENT DIAGNOSIS >
CEF
G H
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K L
M A
B
TM
N
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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

TM-82
< COMPONENT DIAGNOSIS >
P1757 FRONT BRAKE SOLENOID
P1757 FRONT BRAKE SOLENOID
DescriptionINFOID:0000000001604130
Front brake solenoid valve is controlled by the TCM in response to signals sent from the transmission range
switch, output speed sensor and accelerator pedal position sensor (throttle position sensor). Gears will then
be shifted to the optimum position.
CONSULT-III Reference Value in Data Monitor ModeINFOID:0000000001604131
On Board Diagn osis LogicINFOID:0000000001604132
• This is an OBD-II self-diagnostic item.
• Diagnostic trouble code “P1757” with CONSULT-III is detected under the following conditions.
- When TCM detects an improper voltage drop when it tries to operate the solenoid valve.
- When TCM detects as irregular by comparing target value with monitor value.
Possible CauseINFOID:0000000001604133
• Harness or connectors (The solenoid circuit is open or shorted.)
• Front brake solenoid valve
DTC Confirmation ProcedureINFOID:0000000001604134
CAUTION:
Always drive vehicle at a safe speed.
NOTE:
If “DTC Confirmation Procedure” has been previously performed, always turn ignition switch “OFF”
and wait at least 10 seconds before performing the next test.
After the repair, perform the following proc edure to confirm the malfunction is eliminated.
WITH CONSULT-III
1. Turn ignition switch “ON”. (Do not start engine.)
2. Select “DATA MONITOR” mode for “TRANSMISSION” with CONSULT-III.
3. Start engine.
4. Drive vehicle and maintain the following conditions for at least 5 consecutive seconds.
ACCELE POS: 1.5/8 - 2.0/8
Selector lever: “D” position
Gear position: 3rd ⇒ 4GR (FR/B ON/OFF)
Driving location: Driving the vehicle uphill (increased engine load) will help maintain the driving
conditions required for this test.
5. If DTC is detected go to TM-82, "
Diagnosis Procedure".
WITH GST
Follow the procedure “With CONSULT-III”.
Diagnosis ProcedureINFOID:0000000001604135
1.CHECK INPUT SIGNAL
With CONSULT-III
1. Turn ignition switch “ON”.
2. Select “MAIN SIGNALS” in “DATA MONITO R” mode for “TRANSMISSION” with CONSULT-III.
3. Start engine.
4. Read out the value of “FR/B SOLENOID” while driving.
Item name Condition Display value (Approx.)
FR/B SOLENOID 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