engine INFINITI QX56 2006 Factory Service Manual

AT-158
DTC P1774 LOW COAST BRAKE SOLENOID VALVE FUNCTION
Revision: November 20092006 QX56
Diagnostic ProcedureECS00CJ4
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- 1 6 7 , "
MAIN POWER SUPPLY AND GROUND CIR-
CUIT" .
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 connec-
tor.
OK or NG
OK >> Replace the control valve with TCM. Refer to AT- 2 3 0 , "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 AT- 1 5 7 , "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
AT- 2 0
.ON
Low coast brake disengaged. Refer to AT- 2 0
.OFF
ATF PRES
SW 2 Low coast brake engaged. Refer to
AT- 2 0
.ON
Low coast brake disengaged. Refer to AT- 2 0
.OFF
SCIA4794E

DTC P1841 ATF PRESSURE SWITCH 1AT-159
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G H
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M A
B
AT
Revision: November 2009 2006 QX56
DTC P1841 ATF PRESSURE SWITCH 1PFP:25240
DescriptionECS00CJ5
Fail-safe function to detect front brake clutch solenoid valve condition.
CONSULT-II Reference ValueECS00CJ6
On Board Diagnosis LogicECS00CJ7

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 CauseECS00CJ8

ATF pressure switch 1

Harness or connectors
(The switch circuit is open or shorted.)
DTC Confirmation ProcedureECS00CJ9
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- 1 6 0 , "
Diagnostic Procedure" .
If DTC (P1757) is detected, go to AT- 1 4 4 , "
Diagnostic Procedure" .
Item nameCondition Display value
ATF PRES SW 1 Front brake engaged. Refer to
AT- 2 0
.ON
Front brake disengaged. Refer to AT- 2 0
.OFF
BCIA0030E

AT-160
DTC P1841 ATF PRESSURE SWITCH 1
Revision: November 20092006 QX56
Diagnostic ProcedureECS00CJA
1. CHECK INPUT SIGNAL
With CONSULT-II
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- 1 6 7 , "
MAIN POWER SUPPLY AND GROUND CIR-
CUIT" .
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 connec-
tor.
OK or NG
OK >> Replace the control valve with TCM. Refer to AT- 2 3 0 , "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 AT- 1 5 9 , "DTC Confirmation Procedure" .
OK or NG
OK >> INSPECTION END
NG >> GO TO 2.
Item name Condition Display value
ATF PRES
SW 1 Front brake engaged. Refer to
AT- 2 0
.ON
Front brake disengaged. Refer to AT- 2 0
.OFF
PCIA0067E

DTC P1843 ATF PRESSURE SWITCH 3AT-161
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G H
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K L
M A
B
AT
Revision: November 2009 2006 QX56
DTC P1843 ATF PRESSURE SWITCH 3PFP:25240
DescriptionECS00CJB
Fail-safe function to detect input clutch solenoid valve condition.
CONSULT-II Reference ValueECS00CJC
On Board Diagnosis LogicECS00CJD

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 CauseECS00CJE

ATF pressure switch 3

Harness or connectors
(The switch circuit is open or shorted.)
DTC Confirmation ProcedureECS00CJF
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- 1 6 2 , "
Diagnostic Procedure" .
If DTC (P1752) is detected, go to AT- 1 4 0 , "
Diagnostic Procedure" .
Item nameCondition Display value
ATF PRES SW 3 Input clutch engaged. Refer to
AT- 2 0
.ON
Input clutch disengaged. Refer to AT- 2 0
.OFF
BCIA0030E

AT-162
DTC P1843 ATF PRESSURE SWITCH 3
Revision: November 20092006 QX56
Diagnostic ProcedureECS00CJG
1. CHECK INPUT SIGNAL
With CONSULT-II
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- 1 6 7 , "
MAIN POWER SUPPLY AND GROUND CIR-
CUIT" .
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 connec-
tor.
OK or NG
OK >> Replace the control valve with TCM. Refer to AT- 2 3 0 , "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 AT- 1 6 1 , "DTC Confirmation Procedure" .
OK or NG
OK >> INSPECTION END
NG >> GO TO 2.
Item name Condition Display value
ATF PRES
SW 3 Input clutch engaged. Refer to
AT- 2 0
.ON
Input clutch disengaged. Refer to AT- 2 0
.OFF
PCIA0067E

DTC P1845 ATF PRESSURE SWITCH 5AT-163
DE
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G H
I
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K L
M A
B
AT
Revision: November 2009 2006 QX56
DTC P1845 ATF PRESSURE SWITCH 5PFP:25240
DescriptionECS00CJH
Fail-safe function to detect direct clutch solenoid valve condition.
CONSULT-II Reference ValueECS00CJI
On Board Diagnosis LogicECS00CJJ

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 CauseECS00CJK

ATF pressure switch 5

Harness or connectors
(The switch circuit is open or shorted.)
DTC Confirmation ProcedureECS00CJL
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- 1 6 4 , "
Diagnostic Procedure" .
If DTC (P1762) is detected, go to AT- 1 4 8 , "
Diagnostic Procedure" .
Item nameCondition Display value
ATF PRES SW 5 Direct clutch engaged. Refer to
AT- 2 0
.ON
Direct clutch disengaged. Refer to AT- 2 0
.OFF
BCIA0030E

AT-164
DTC P1845 ATF PRESSURE SWITCH 5
Revision: November 20092006 QX56
Diagnostic ProcedureECS00CJM
1. CHECK INPUT SIGNAL
With CONSULT-II
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- 1 6 7 , "
MAIN POWER SUPPLY AND GROUND CIR-
CUIT" .
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 connec-
tor.
OK or NG
OK >> Replace the control valve with TCM. Refer to AT- 2 3 0 , "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 AT- 1 6 3 , "DTC Confirmation Procedure" .
OK or NG
OK >> INSPECTION END
NG >> GO TO 2.
Item name Condition Display value
ATF PRES
SW 5 Direct clutch egaged. Refer to
AT- 2 0
.ON
Direct clutch disegaged. Refer to AT- 2 0
.OFF
PCIA0067E

DTC P1846 ATF PRESSURE SWITCH 6AT-165
DE
F
G H
I
J
K L
M A
B
AT
Revision: November 2009 2006 QX56
DTC P1846 ATF PRESSURE SWITCH 6PFP:25240
DescriptionECS00CJN
Fail-safe function to detect high and low reverse clutch solenoid valve condition.
CONSULT-II Reference ValueECS00CJO
On Board Diagnosis LogicECS00CJP

This is not an OBD-II self-diagnostic item.

Diagnostic trouble code “P1846 ATF PRES SW 6/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 6
is irregular during depressing accelerator pedal. (Other than during shift change)
Possible CauseECS00CJQ

ATF pressure switch 6

Harness or connectors
(The switch circuit is open or shorted.)
DTC Confirmation ProcedureECS00CJR
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: 2nd
3rd Gear (HLR/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 (P1846) is detected, go to AT- 1 6 6 , "
Diagnostic Procedure" .
If DTC (P1767) is detected, go to AT- 1 5 2 , "
Diagnostic Procedure" .
Item nameCondition Display value
ATF PRES SW 6 High and low reverse clutch engaged. Refer to
AT- 2 0
.ON
High and low reverse clutch disengaged. Refer to AT- 2 0
.OFF
BCIA0030E

AT-166
DTC P1846 ATF PRESSURE SWITCH 6
Revision: November 20092006 QX56
Diagnostic ProcedureECS00CJS
1. CHECK INPUT SIGNAL
With CONSULT-II
1. Start the 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 (2nd
3rd gear), and confirm
the ON/OFF actuation of the “ATF PRES SW 6”.
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- 1 6 7 , "
MAIN POWER SUPPLY AND GROUND CIR-
CUIT" .
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 connec-
tor.
OK or NG
OK >> Replace the control valve with TCM. Refer to AT- 2 3 0 , "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 AT- 1 6 5 , "DTC Confirmation Procedure" .
OK or NG
OK >> INSPECTION END
NG >> GO TO 2.
Item name Condition Display value
ATF PRES
SW 6 High and low reverse clutch engaged.
Refer to
AT- 2 0
. ON
High and low reverse clutch disengaged.
Refer to AT- 2 0
. OFFPCIA0067E

AT-168
MAIN POWER SUPPLY AND GROUND CIRCUIT
Revision: November 20092006 QX56
TCM terminals and data are reference value. Measured between each terminal and ground.
Diagnostic ProcedureECS00CJU
1. CHECK TCM POWER SOURCE STEP 1
1. Turn ignition switch OFF.
2. Disconnect A/T assembly harness connector.
3. Check voltage between A/T assembly harness connector termi- nals and ground.
OK or NG
OK >> GO TO 2.
NG >> GO TO 3.
2. CHECK TCM POWER SOURCE STEP 2
1. Disconnect A/T assembly harness connector.
2. Turn ignition switch ON. (Do not start engine.)
3. Check voltage between A/T assembly harness connector termi- nals and ground.
OK or NG
OK >> GO TO 4.
NG >> GO TO 3.
Terminal Wire
color Item
ConditionData (Approx.)
1P Power supply
(Memory back-up) Always
Battery voltage
2P Power supply
(Memory back-up)
Always
Battery voltage
5 B Ground Always0V
6 Y/R Power supply –
Battery voltage
– 0V
10 B Ground Always0V
ItemConnector TerminalVoltage
TCM F91 - Ground
Battery voltage
2 - Ground
6 - Ground 0V
SCIA2104E
ItemConnector TerminalVoltage
TCM F441 - Ground
Battery voltage
2 - Ground
6 - Ground
SCIA2105E