2009 INFINITI QX56 sensor

TM-90
< COMPONENT DIAGNOSIS >
P1774 LOW COAST BRAKE SOLENOID
P1774 LOW COAST BRAKE SOLENOID
DescriptionINFOID:0000000003771969
 Low coast brake solenoid valve is turned “ON” or “OFF” by the TCM in response to signals sent from the
transmission range switch, output speed sensor and accele rator pedal position sensor (throttle position sen-
sor). Gears will then be shifted to the optimum position.
 This is not only caused by electrical malfunction (cir cuits open or shorted) but also by mechanical malfunc-
tion such as control valve sticking, improper solenoid valve operation.
CONSULT-III Reference Value in Data Monitor ModeINFOID:0000000003771970
On Board Diagn osis LogicINFOID:0000000003771971
 This is an OBD-II self-diagnostic item.
 Diagnostic trouble code “P1774” with CONSULT-III is detected under the following conditions.
- When TCM detects that actual gear ratio is irr egular, and relation between gear position and condition of
ATF pressure switch 2 is irregular during depressing accelerator pedal. (Other than during shift change)
- When TCM detects that relation between gear position and condition of ATF pressure switch 2 is irregular
during releasing accelerator pedal. (Other than during shift change)
Possible CauseINFOID:0000000003771972
 Harness or connectors
(The solenoid and switch circuits are open or shorted.)
 Low coast brake solenoid valve
 ATF pressure switch 2
DTC Confirmation ProcedureINFOID:0000000003771973
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. Start engine.
2. Accelerate vehicle to maintain the following conditions.
SLCT LVR POSI: “1” or “2” position
GEAR: “1st” or “2nd” (LC/B ON/OFF)
3. Perform step “2” again.
4. Turn ignition switch “OFF”, then perform step “1” to “3” again.
5. Check “SELF-DIAG RESULTS” mode for “TRANS MISSION” with CONSULT-III. If DTC (P1774) is
detected, refer to TM-90, "Diagnosis Procedure"
.
If DTC (P1772) is detected, go to TM-88, "Diagnosis Procedure"
.
WITH GST
Follow the procedure “With CONSULT-III”.
Diagnosis ProcedureINFOID:0000000003771974
1.CHECK INPUT SIGNALS
Item name Condition Display value
ON OFF SOLLow 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: December 20092009 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-203, "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: December 20092009 QX56

MAIN POWER SUPPLY AND GROUND CIRCUITTM-93
< COMPONENT DIAGNOSIS >
CEF
G H
I
J
K L
M A
B
TM
N
O P
5.DETECT MALFUNCTIONING ITEM
Check the following items:
 The A/T assembly harness connector terminals for damage or loose connection with harness connector.
OK or NG
OK >> GO TO 6.
NG >> Repair or replace damaged parts.
6.PERFORM SELF-DIAGNOSIS
Perform self-diagnosis. Refer to TM-32, "CONSULT-III Function (TRANSMISSION)"
.
OK or NG
OK >> INSPECTION END
NG-1 >> Self-diagnosis does not activate: GO TO 7.
NG-2 >> DTC is displayed: Check t he malfunctioning system. Refer to TM-32, "CONSULT-III Function
(TRANSMISSION)".
7.CHECK TERMINAL CORD ASSEMBLY
1. Remove control valve with TCM. Refer to TM-203, "Control Valve with TCM and A/T Fluid Temperature
Sensor 2".
2. Disconnect A/T assembly harness connector and TCM connector.
3. Check continuity between A/T assembly harness connector ter- minals and TCM connector terminals.
4. Check continuity between A/T assembly harness connector ter- minals and TCM connector terminals.
5. If OK, check harness for short to ground and short to power.
OK or NG
OK >> Replace the control valve with TCM. Refer to TM-203, "Control Valve with TCM and A/T Fluid
Temperature Sensor 2".
NG >> Replace open circuit or short to ground and short to power in harness or connectors.
Item Connector Terminal Continuity
A/T assembly harness con-
nector F9 1
Ye s
TCM connector F502 9
A/T assembly harness con-
nector F9 2
Ye s
TCM connector F502 10
A/T assembly harness con-
nector F9 6
Ye s
TCM connector F502 4
SCIA5464E
Item Connector Terminal Continuity
A/T assembly harness con-
nector F9 5
Ye s
TCM connector F504 21
A/T assembly harness con-
nector F9 10
Ye s
TCM connector F504 22
SCIA5465E
Revision: December 20092009 QX56

TM-116
< ECU DIAGNOSIS >
TCM
Even when the electronic circuits are normal, under special conditions (for example, when slamming on the
brake with the wheels spinning drastically and stopping t he tire rotation), the transmission can go into fail-safe
mode. If this happens, switch “OFF” the ignition switch for 10 seconds, then switch it “ON” again to return to
the normal shift pattern. Therefore, the customer's v ehicle has returned to normal, so handle according to the
“diagnostics flow” (Refer to TM-5, "Work Flow"
).
FAIL-SAFE FUNCTION
If any malfunction occurs in a sensor or solenoid, th is function controls the A/T to mark driving possible.
Output Speed Sensor
 Signals are input from two systems - from output s peed sensor installed on the transmission and from com-
bination meter so normal driving is possible even if ther e is a malfunction in one of the systems. And if output
speed sensor has unusual cases, 5GR is prohibited.
Accelerator Peda l Position Sensor
 If there is a malfunction in one of the systems, the accelerator opening angle is controlled by ECM according
to a pre-determined accelerator angle to make driving possible. And if there are malfunctions in tow sys-
tems, the engine speed is fixed by ECM to a pre-determined engine speed to make driving possible.
Throttle Position Sensor
 If there is a malfunction in one of the systems, the accelerator opening angle is controlled by ECM according
to a pre-determined accelerator angle to make driving possible. And if there are malfunctions in tow sys-
tems, the accelerator opening angle is controlled by the idle signal sent from the ECM which is based on
input indicating either idle condition or off-idle condition (pre-determined accelerator opening) in order to
make driving possible.
Transmission Range Switch
 In the unlikely event that a malfunction signal enters t he TCM, the position indicator is switched “OFF”, the
starter relay is switched “OFF” (starter starting is disabled), the back-up lamp relay switched “OFF” (back-up
lamp is OFF) and the position is fixed to the “D” range to make driving possible.
Starter Relay
 The starter relay is switched “OFF”. (Starter starting is disabled.)
Interlock
 If there is an interlock judgment malfunction, the trans mission is fixed in 2GR to make driving possible.
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 the interlock is detected at the 3GR or more, it is locked at the 2GR.
1st Engine Braking
 When there is an 1st gear engine brake judgment malfunc tion, the low coast brake solenoid is switched
“OFF” to avoid the engine brake operation.
Line Pressure Solenoid
 The solenoid is switched “OFF” and the line pressure is se t to the maximum hydraulic pressure to make driv-
ing possible.
Torque Converter Clutch Solenoid
 The solenoid is switched “OFF” to release the lock-up.
Low Coast Brake Solenoid
 When a (electrical or functional) malfunction occurs, in order to make driving possible, the engine brake is not applied in 1GR and 2GR.
Input Clutch Solenoid
 If a (electrical or functional) malfunction occurs with the solenoid either “ON” or “OFF”, the transmission is
held in 4GR to make driving possible.
Direct Clutch Solenoid
 If a (electrical or functional) malfunction occurs with the solenoid either “ON” or “OFF”, the transmission is
held in 4GR to make driving possible.
Front Brake Solenoid
 If a (electrical or functional) malfunction occurs with the solenoid “ON”, in order to make driving possible, the
A/T is held in 5GR; if the solenoid is OFF, 4GR.
Revision: December 20092009 QX56

TCM
TM-117
< ECU DIAGNOSIS >
C EF
G H
I
J
K L
M A
B
TM
N
O P
High and Low Revers
e Clutch Solenoid
 If a (electrical or functional) malfunction occurs with the solenoid either “ON” or “OFF”, the transmission is
held in 4th gear to make driving possible.
Input Speed Sensor 1 or 2
 The control is the same as if there were no input speed sensors, 5GR is prohibited.
DTC Inspection Priority ChartINFOID:0000000003771988
If some DTCs are displayed at the same time, per form inspections one by one based on the following priority
chart.
NOTE:
If DTC U1000 is displayed with other DTCs, first pe rform the trouble diagnosis for DTC U1000. Refer to
TM-39, "Diagnosis Procedure"
.
DTC No. IndexINFOID:0000000003771989
NOTE:
If DTC U1000 is displayed with other DTC, first pe rform the trouble diagnosis for DTC U1000. Refer to
TM-39, "Diagnosis Procedure"
.
Priority Detected items (DTC)
1 U1000 CAN COMM CIRCUT
2 Except above
DTC Items
(CONSULT- III screen terms) Reference page
OBD- II Except OBD- II
CONSULT- III GST (*1) CONSULT- III only
“TRANSMISSION”
— P0615 STARTER RELAY TM-40
P0700 P0700 TRANSMISSION CONT TM-43
P0705 P0705 T/M RANGE SWITCH ATM-44
P0710 P1710 TRANS FLUID TEMP SENTM-72
P0717 P0717 INPUT SPEED SENSOR ATM-47
P0720 P0720 OUTPUT SPEED SENSORTM-50
— P0725 ENGINE SPEEDTM-52
P0731 P0731 1GR INCORRECT RATIO TM-55
P0732 P0732 2GR INCORRECT RATIOTM-57
P0733 P0733 3GR INCORRECT RATIOTM-59
P0734 P0734 4GR INCORRECT RATIOTM-61
P0735 P0735 5GR INCORRECT RATIOTM-63
P0740 P0740 TORQUE CONVERTERTM-64
P0744 P0744 TORQUE CONVERTERTM-67
P0745 P0745 PC SOLENOID ATM-68
— P1705 TP SENSORTM-70
— P1721 VEHICLE SPEED SIGNALTM-74
P1730 P1730 INTERLOCK TM-76
— P1731 1GR E/BRAKINGTM-78
P1752 P1752 INPUT CLUTCH SOLENOID TM-80
P1757 P1757 FR BRAKE SOLENOIDTM-82
P1762 P1762 DRCT CLUTCH SOLENOIDTM-84
P1767 P1767 HLR CLUTCH SOLLENOIDTM-86
Revision: December 20092009 QX56

TM-118
< ECU DIAGNOSIS >
TCM
*1: These numbers are prescribed by SAE J2012.
*2: These malfunctions cannot be displayed MIL if another malfunction is assigned to MIL.
DTC Alphabetical IndexINFOID:0000000003771990
NOTE:
If DTC U1000 is displayed with other DTC, first perform the trouble diagnosis for DTC U1000. Refer to
TM-39, "Diagnosis Procedure"
.
*1: These numbers are prescribed by SAE J2012.
*2: These malfunctions cannot be displayed MIL if another malfunction is assigned to MIL. P1772 P1772 L C BRAKE SOLENOID
TM-88
P1774 (2*) P1774 L C BRAKE SOLENOID TM-90
U1000 U1000 CAN COMM CIRCUITTM-39
DTC
Items
(CONSULT- III screen terms) Reference page
OBD- II Except OBD- II
CONSULT- III GST (*1) CONSULT- III only
“TRANSMISSION”
Items
(CONSULT- III screen terms) DTC
Reference page
OBD- II Except OBD- II
CONSULT- III GST (*1) CONSULT- III only
“TRANSMISSION”
1ST E/BRAKING — P1731 TM-78
1GR INCORRECT RATIO P0731 P0731TM-55
2GR INCORRECT RATIO P0732 P0732TM-57
3GR INCORRECT RATIO P0733 P0733TM-59
4GR INCORRECT RATIO P0734 P0734TM-61
5GR INCORRECT RATIO P0735 P0735TM-63
INTERLOCK P1730 P1730TM-76
TORQUE CONVERTER P0744 P0744 TM-67
TRAXIS FLUID TEMP SEN P0710 P1710TM-72
CAN COMM CIRCUIT U1000 U1000TM-39
DRCT CLUTCH SOLENOID P1762 P1762 TM-84
ENGINE SPEED — P0725 TM-52
FR BRAKE SOLENOID P1757 P1757TM-82
HLR CLUTCH SOLENOID P1767 P1767TM-86
INPUT CLUTCH SOLENOID P1752 P1752TM-80
PC SOLENOID A P0745 P0745TM-68
LC BRAKE SOLENOID P1772 P1772TM-88
LC BRAKE SOLENOID P1774 P1774 TM-90
T/M RANGE SWITCH A P0705 P0705TM-44
STARTER RELAY — P0615TM-40
TORQUE CONVERTER P0740 P0740TM-64
TRANSMISSION CONT P0700 P0700TM-43
TP SENSOR — P1705TM-70
INPUT SPEED SENSOR A P0717 P0717TM-47
VEHICLE SPEED SIGNAL — P1721TM-74
OUTPUT SPEED SENSOR P0720 P0720TM-50
Revision: December 20092009 QX56

TM-122
< SYMPTOM DIAGNOSIS >
SYSTEM SYMPTOM
OK >>INSPECTION END
NG >> Repair or replace damaged parts.
Large Shock("N" to "D" Position)INFOID:0000000003771995
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 TM-32, "CONSULT-III Function (TRANSMISSION)"
.
Do the self-diagnostic results indicate A/T fluid temperature sensor, engine speed signal, accelerator pedal
position sensor, front brake solenoid valve, CAN communication line?
YES >> Check the malfunctioning system. Refer to TM-72, "Diagnosis Procedure", TM-52, "Diagnosis
Procedure", TM-70, "Diagnosis Procedure", TM-82, "Diagnosis Procedure", TM-39, "Diagnosis
Procedure".
NO >> GO TO 2.
2.ENGINE IDLE SPEED
Check the engine idle speed. Refer to EC-17, "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 TM-195, "Checking of A/T Position"
.
OK or NG
OK >> GO TO 4.
NG >> Adjust control cable. Refer to TM-195, "Adjustment of A/
T Position".
4.CHECK A/T FLUID LEVEL
Check the A/T fluid level. Refer to TM-179, "Checking the A/T Fluid
(ATF)".
OK or NG
OK >> GO TO 5.
NG >> Refill ATF.
5.CHECK LINE PRESSURE
LCIA0345E
SAT638A
Revision: December 20092009 QX56

TM-124
< SYMPTOM DIAGNOSIS >
SYSTEM SYMPTOM
OK >>INSPECTION END
NG >> GO TO 11.
11 .PERFORM TCM INSPECTION
1. Perform TCM input/output signals inspection. Refer to TM-104, "Reference Value"
.
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.
Vehicle Does Not Creep Ba ckward in "R" PositionINFOID:0000000003771996
SYMPTOM:
The vehicle does not creep in th e “R” position. Or an extreme lack of acceleration is observed.
DIAGNOSTIC PROCEDURE
1.CHECK SELF-DIAGNOSTIC RESULTS
Perform self-diagnosis. Refer to TM-32, "CONSULT-III Function (TRANSMISSION)"
.
Do the self-diagnostic results indicate accelerator pedal position sensor, high and low reverse clutch solenoid
valve, CAN communication line, transmission range switch?
YES >> Check the malfunctioning system. Refer to TM-70, "Diagnosis Procedure", TM-86, "Diagnosis
Procedure", TM-44, "Diagnosis Procedure", TM-39, "Diagnosis Procedure".
NO >> GO TO 2.
2.CHECK CONTROL CABLE
Check the control cable.
 Refer to TM-195, "Checking of A/T Position"
.
OK or NG
OK >> GO TO 3.
NG >> Adjust control cable. Refer to TM-195, "Adjustment of A/
T Position".
3.CHECK A/T FLUID LEVEL
Check A/T fluid level. Refer to TM-179, "Checking the A/T Fluid
(ATF)".
OK or NG
OK >> GO TO 4.
NG >> Refill ATF.
4.CHECK STALL TEST
Check stall revolution with selector lever in “1” and “R” positions.
LCIA0345E
SAT638A
Revision: December 20092009 QX56