2009 INFINITI QX56 brake sensor

TM-76
< COMPONENT DIAGNOSIS >
P1730 INTERLOCK
P1730 INTERLOCK
DescriptionINFOID:0000000003771927
 Fail-safe function to detect interlock conditions.
On Board Diagnosis LogicINFOID:0000000003771928
 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:0000000003771929
 Harness or connectors
(The solenoid and switch circuit is open or shorted.)
 Low coast brake solenoid valve
 ATF pressure switch 2
DTC Confirmation ProcedureINFOID:0000000003771930
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. SLCT LVR POSI: “D” position
5. If DTC is detected, go to TM-76, "Diagnosis Procedure"
.
WITH GST
Follow the procedure “With CONSULT-III”.
Judgement of InterlockINFOID:0000000003771931
 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, an input speed s ensor 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:0000000003771932
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: December 20092009 QX56

TM-78
< COMPONENT DIAGNOSIS >
P1731 1ST ENGINE BRAKING
P1731 1ST ENGINE BRAKING
DescriptionINFOID:0000000003771933
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:0000000003771934
On Board Diagnosis LogicINFOID:0000000003771935
 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:0000000003771936
 Harness or connectors
(The sensor circuit is open or shorted.)
 Low coast brake solenoid valve
 ATF pressure switch 2
DTC Confirmation ProcedureINFOID:0000000003771937
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
SLCT LVR POSI: “1” position
GEAR: 1st gear
5. If DTC is detected, go to TM-78, "Diagnosis Procedure"
.
Diagnosis ProcedureINFOID:0000000003771938
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
.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
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
Revision: December 20092009 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-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-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: December 20092009 QX56

TM-82
< COMPONENT DIAGNOSIS >
P1757 FRONT BRAKE SOLENOID
P1757 FRONT BRAKE SOLENOID
DescriptionINFOID:0000000003771945
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:0000000003771946
On Board Diagn osis LogicINFOID:0000000003771947
 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:0000000003771948
 Harness or connectors
(The solenoid circuit is open or shorted.)
 Front brake solenoid valve
DTC Confirmation ProcedureINFOID:0000000003771949
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 POSI: 1.5/8 - 2.0/8
SLCT LVR POSI: “D” position
GEAR: 3rd ⇒ 4th (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:0000000003771950
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: December 20092009 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-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-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: December 20092009 QX56

TM-88
< COMPONENT DIAGNOSIS >
P1772 LOW COAST BRAKE SOLENOID
P1772 LOW COAST BRAKE SOLENOID
DescriptionINFOID:0000000003771963
Low coast brake solenoid valve is turned “ON” or “OFF” by the TCM in response to signals sent from the trans-
mission range switch, output speed sensor and accelerato r pedal position sensor (throttle position sensor).
Gears will then be shifted to the optimum position.
CONSULT-III Reference Value in Data Monitor ModeINFOID:0000000003771964
On Board Diagn osis LogicINFOID:0000000003771965
 This is an OBD-II self-diagnostic item.
 Diagnostic trouble code “P1772” with CONSULT-III is detected when TCM detects an improper voltage drop
when it tries to operate the solenoid valve.
Possible CauseINFOID:0000000003771966
 Harness or connectors (The solenoid circuit is open or shorted.)
 Low coast brake solenoid valve
DTC Confirmation ProcedureINFOID:0000000003771967
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 “ENGINE” with CONSULT-III.
3. Start engine.
4. Drive vehicle and maintain the following conditions for at least 5 consecutive seconds.
SLCT LVR POSI: “1” or “2”
GEAR: “1st” or “2nd” (LC/B ON/OFF)
5. If DTC is detected, go to TM-88, "Diagnosis Procedure"
.
WITH GST
Follow the procedure “With CONSULT-III”.
Diagnosis ProcedureINFOID:0000000003771968
1.CHECK INPUT SIGNAL
With CONSULT-III
1. Turn ignition switch “ON”.
2. Select “SELECTION FROM MENU” in “DATA MONI TOR” mode for “TRANSMISSION” with CONSULT-III.
3. Start the engine.
4. Read out the value of “ON OFF SOL” while driving.
OK or NG
OK >> GO TO 4.
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
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
Revision: December 20092009 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-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-88, "DTC Confirmation Procedure"
.
OK or NG
OK >> INSPECTION END
NG >> GO TO 2.
Revision: December 20092009 QX56

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