2007 INFINITI QX56 check engine

AT-148
< SERVICE INFORMATION >
DTC P1774 LOW COAST BRAKE SOLENOID VALVE FUNCTION
DTC P1774 LOW COAST BRAKE SOLENOID VALVE FUNCTION
DescriptionINFOID:0000000003532408
• Low coast brake solenoid valve is turned “ON” or “OFF” by the TCM in response to signals sent from the
PNP switch, vehicle speed sensor and accelerator pedal position sensor (throttle position sensor). Gears will
then be shifted to the optimum position.
• This is not only caused by electrical malfunction (circuits open or shorted) but also by mechanical malfunc-
tion such as control valve sticking, improper solenoid valve operation.
CONSULT-II Reference Value in Data Monitor ModeINFOID:0000000003532409
On Board Diagnosis LogicINFOID:0000000003532410
• This is an OBD-II self-diagnostic item.
• Diagnostic trouble code “P1774 LC/B SOLENOID FNCT” with CONSULT-II is detected under the following
conditions.
- When TCM detects that actual gear ratio is irregular, 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:0000000003532411
• Harness or connectors
(The solenoid and switch circuits are open or shorted.)
• Low coast brake solenoid valve
• ATF pressure switch 2
DTC Confirmation ProcedureINFOID:0000000003532412
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 procedure to confirm the malfunction is eliminated.
WITH CONSULT-II
1. Start engine.
2. Accelerate vehicle to maintain the following conditions.
Selector lever: “1” or “2” position
Gear position: “1st” or “2nd” gear (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 “A/T” with CONSULT-
II. If DTC (P1774) is detected, refer to AT-149, "
Diagnosis Pro-
cedure".
If DTC (P1772) is detected, go to AT-146, "
Diagnosis Proce-
dure".
WITH GST
Follow the procedure “With CONSULT-II”.
Item name Condition Display value
ON OFF SOLLow coast brake engaged. Refer to AT- 2 0
.ON
Low coast brake disengaged. Refer to AT- 2 0
.OFF
ATF PRES SW 2Low coast brake engaged. Refer to AT- 2 0
.ON
Low coast brake disengaged. Refer to AT- 2 0
.OFF
BCIA0031E

DTC P1774 LOW COAST BRAKE SOLENOID VALVE FUNCTION
AT-149
< SERVICE INFORMATION >
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Diagnosis ProcedureINFOID:0000000003532413
1.CHECK INPUT SIGNALS
With CONSULT-II
1. Start the engine.
2. Select “SELECTION FROM MENU” in “DATA MONITOR” mode
for “A/T” with CONSULT-II.
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 AT-158
.
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 AT-210, "Control Valve with TCM and A/T Fluid Tem-
perature Sensor 2".
NG >> Repair or replace damaged parts.
4.CHECK DTC
Perform “DTC Confirmation Procedure”.
• Refer to AT-148, "
DTC Confirmation Procedure".
OK or NG
OK >>INSPECTION END
NG >> GO TO 2.
Item name Condition Display value
ON OFF SOLLow coast brake engaged. Refer to AT- 2 0
.ON
Low coast brake disengaged. Refer to AT- 2 0
.OFF
ATF PRES
SW 2Low coast brake engaged. Refer to AT- 2 0
.ON
Low coast brake disengaged. Refer to AT- 2 0
.OFF
SCIA4794E

AT-150
< SERVICE INFORMATION >
DTC P1841 ATF PRESSURE SWITCH 1
DTC P1841 ATF PRESSURE SWITCH 1
DescriptionINFOID:0000000003532414
Fail-safe function to detect front brake clutch solenoid valve condition.
CONSULT-II Reference Value in Data Monitor ModeINFOID:0000000003532415
On Board Diagnosis LogicINFOID:0000000003532416
• This is not an OBD-II self-diagnostic item.
• Diagnostic trouble code “P1841 ATF PRES SW 1/CIRC” with CONSULT-II is detected when TCM detects
that actual gear ratio is normal, and relation between gear position and condition of ATF pressure switch 1 is
irregular during depressing accelerator pedal. (Other than during shift change)
Possible CauseINFOID:0000000003532417
• ATF pressure switch 1
• Harness or connectors
(The switch circuit is open or shorted.)
DTC Confirmation ProcedureINFOID:0000000003532418
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 procedure to confirm the malfunction is eliminated.
WITH CONSULT-II
1. Start engine.
2. Accelerate vehicle to maintain the following conditions.
ACCELE POS: 1.5/8 - 2.0/8
Selector lever: “D” position
Gear position: 3rd ⇒ 4th Gear (FR/B ON/OFF)
Driving location: Driving the vehicle uphill (increased
engine load) will help maintain the driving conditions
required for this test.
3. Perform step “2” again.
4. Turn ignition switch “OFF”, then perform step “1” to “3” again.
5. Check “SELF-DIAG RESULTS” mode for “A/T” with CONSULT-
II.
If DTC (P1841) is detected, go to AT-150, "
Diagnosis Procedure".
If DTC (P1757) is detected, go to AT-134, "
Diagnosis Procedure".
Diagnosis ProcedureINFOID:0000000003532419
1.CHECK INPUT SIGNAL
With CONSULT-II
Item name Condition Display value
ATF PRES SW 1Front brake engaged. Refer to AT- 2 0
.ON
Front brake disengaged. Refer to AT- 2 0
.OFF
BCIA0031E

DTC P1841 ATF PRESSURE SWITCH 1
AT-151
< SERVICE INFORMATION >
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1. Start engine.
2. Select “ECU INPUT SIGNALS” or “MAIN SIGNALS” in “DATA
MONITOR” mode for “A/T” with CONSULT-II.
3. Drive vehicle in the “D” position (3rd ⇒ 4th gear), and confirm
the ON/OFF actuation of the “ATF PRES SW 1”.
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 AT-158
.
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 AT-210, "Control Valve with TCM and A/T Fluid Tem-
perature Sensor 2".
NG >> Repair or replace damaged parts.
4.CHECK DTC
Perform “DTC Confirmation Procedure”.
• Refer to AT-150, "
DTC Confirmation Procedure".
OK or NG
OK >>INSPECTION END
NG >> GO TO 2.
Item name Condition Display value
ATF PRES
SW 1Front brake engaged. Refer to AT- 2 0
.ON
Front brake disengaged. Refer to AT- 2 0
.OFF
PCIA0067E

AT-152
< SERVICE INFORMATION >
DTC P1843 ATF PRESSURE SWITCH 3
DTC P1843 ATF PRESSURE SWITCH 3
DescriptionINFOID:0000000003532420
Fail-safe function to detect input clutch solenoid valve condition.
CONSULT-II Reference Value in Data Monitor ModeINFOID:0000000003532421
On Board Diagnosis LogicINFOID:0000000003532422
• This is not an OBD-II self-diagnostic item.
• Diagnostic trouble code “P1843 ATF PRES SW 3/CIRC” with CONSULT-II is detected when TCM detects
that actual gear ratio is normal, and relation between gear position and condition of ATF pressure switch 3 is
irregular during depressing accelerator pedal. (Other than during shift change)
Possible CauseINFOID:0000000003532423
• ATF pressure switch 3
• Harness or connectors
(The switch circuit is open or shorted.)
DTC Confirmation ProcedureINFOID:0000000003532424
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 procedure to confirm the malfunction is eliminated.
WITH CONSULT-II
1. Start engine.
2. Accelerate vehicle to maintain the following conditions.
ACCELE POS: 1.5/8 - 2.0/8
Selector lever: “D” position
Gear position: 3rd ⇒ 4th Gear (I/C ON/OFF)
Driving location: Driving the vehicle uphill (increased
engine load) will help maintain the driving conditions
required for this test.
3. Perform step “2” again.
4. Turn ignition switch “OFF”, then perform step “1” to “3” again.
5. Check “SELF-DIAG RESULTS” mode for “A/T” with CONSULT-
II.
If DTC (P1843) is detected, go to AT-152, "
Diagnosis Procedure".
If DTC (P1752) is detected, go to AT-130, "
Diagnosis Procedure".
Diagnosis ProcedureINFOID:0000000003532425
1.CHECK INPUT SIGNAL
With CONSULT-II
Item name Condition Display value
ATF PRES SW 3Input clutch engaged. Refer to AT- 2 0
.ON
Input clutch disengaged. Refer to AT- 2 0
.OFF
BCIA0031E

DTC P1843 ATF PRESSURE SWITCH 3
AT-153
< SERVICE INFORMATION >
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1. Start engine.
2. Select “ECU INPUT SIGNALS” or “MAIN SIGNALS” in “DATA
MONITOR” mode for “A/T” with CONSULT-II.
3. Drive vehicle in the “D” position (3rd ⇒ 4th gear), and confirm
the ON/OFF actuation of the “ATF PRES SW 3”.
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 AT-158
.
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 AT-210, "Control Valve with TCM and A/T Fluid Tem-
perature Sensor 2".
NG >> Repair or replace damaged parts.
4.CHECK DTC
Perform “DTC Confirmation Procedure”.
• Refer to AT-152, "
DTC Confirmation Procedure".
OK or NG
OK >>INSPECTION END
NG >> GO TO 2.
Item name Condition Display value
ATF PRES
SW 3Input clutch engaged. Refer to AT- 2 0
.ON
Input clutch disengaged. Refer to AT- 2 0
.OFF
PCIA0067E

AT-154
< SERVICE INFORMATION >
DTC P1845 ATF PRESSURE SWITCH 5
DTC P1845 ATF PRESSURE SWITCH 5
DescriptionINFOID:0000000003532426
Fail-safe function to detect direct clutch solenoid valve condition.
CONSULT-II Reference Value in Data Monitor ModeINFOID:0000000003532427
On Board Diagnosis LogicINFOID:0000000003532428
• This is not an OBD-II self-diagnostic item.
• Diagnostic trouble code “P1845 ATF PRES SW 5/CIRC” with CONSULT-II is detected when TCM detects
that actual gear ratio is normal, and relation between gear position and condition of ATF pressure switch 5 is
irregular during depressing accelerator pedal. (Other than during shift change)
Possible CauseINFOID:0000000003532429
• ATF pressure switch 5
• Harness or connectors
(The switch circuit is open or shorted.)
DTC Confirmation ProcedureINFOID:0000000003532430
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 procedure to confirm the malfunction is eliminated.
WITH CONSULT-II
1. Start engine.
2. Accelerate vehicle to maintain the following conditions.
ACCELE POS: 1.5/8 - 2.0/8
Selector lever: “D” position
Gear position: 1st ⇒ 2nd Gear (D/C ON/OFF)
Driving location: Driving the vehicle uphill (increased
engine load) will help maintain the driving conditions
required for this test.
3. Perform step “2” again.
4. Turn ignition switch “OFF”, then perform step “1” to “3” again.
5. Check “SELF-DIAG RESULTS” mode for “A/T” with CONSULT-
II.
If DTC (P1845) is detected, go to AT-154, "
Diagnosis Procedure".
If DTC (P1762) is detected, go to AT-138, "
Diagnosis Procedure".
Diagnosis ProcedureINFOID:0000000003532431
1.CHECK INPUT SIGNAL
With CONSULT-II
Item name Condition Display value
ATF PRES SW 5Direct clutch engaged. Refer to AT- 2 0
.ON
Direct clutch disengaged. Refer to AT- 2 0
.OFF
BCIA0031E

DTC P1845 ATF PRESSURE SWITCH 5
AT-155
< SERVICE INFORMATION >
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1. Start engine.
2. Select “ECU INPUT SIGNALS” or “MAIN SIGNALS” in “DATA
MONITOR” mode for “A/T” with CONSULT-II.
3. Drive vehicle in the “D” position (1st ⇒ 2nd gear), and confirm
the ON/OFF actuation of the “ATF PRES SW 5”.
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 AT-158
.
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 AT-210, "Control Valve with TCM and A/T Fluid Tem-
perature Sensor 2".
NG >> Repair or replace damaged parts.
4.CHECK DTC
Perform “DTC Confirmation Procedure”.
• Refer to AT-154, "
DTC Confirmation Procedure"
.
OK or NG
OK >>INSPECTION END
NG >> GO TO 2.
Item name Condition Display value
ATF PRES
SW 5Direct clutch engaged. Refer to AT- 2 0
.ON
Direct clutch disengaged. Refer to AT- 2 0
.OFF
PCIA0067E