2004 INFINITI QX56 check engine

AT-158
DTC P1762 DIRECT CLUTCH SOLENOID VALVE
Revision: August 20072004 QX56
Diagnostic ProcedureUCS002GT
1. CHECK INPUT SIGNAL
With CONSULT-II
1. Turn ignition switch “ON”. (Do not start engine.)
2. Select “MAIN SIGNALS” in “DATA MONITOR” mode for “A/T”
with CONSULT-II.
3. Start the engine.
4. Read out the value of “D/C SOLENOID” while driving.
OK or NG
OK >> GO TO 6.
NG >> GO TO 2.
2. CHECK TCM
Perform TCM input/output signals inspection. Refer to AT- 9 0 , "
TCM Input/Output Signal Reference Values" .
OK or NG
OK >> GO TO 3.
NG >> GO TO 5.
3. CHECK DTC
Perform “DTC Confirmation Procedure”.

Refer to AT-157, "DTC Confirmation Procedure" .
OK or NG
OK >>INSPECTION END
NG >> GO TO 4.
4. 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 >> Replace the control valve with TCM. Refer to AT-241, "Control Valve With TCM and A/T Fluid
Temperature Sensor 2" .
NG >> Repair or replace damaged parts.
5. DETECT MALFUNCTIONING ITEM
Check the following items:

Power supply and ground circuit for TCM.

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.
Item name Condition Display value
(Approx.)
D/C SOLE-
NOIDDirect clutch disengaged. Refer to AT- 2 1
. 0.6 - 0.8 A
Direct clutch engaged. Refer to AT - 2 1
. 0 - 0.05 ASCIA4793E

AT-160
DTC P1764 DIRECT CLUTCH SOLENOID VALVE FUNCTION
Revision: August 20072004 QX56
DTC P1764 DIRECT CLUTCH SOLENOID VALVE FUNCTIONPFP:31940
DescriptionUCS002GU

Direct clutch solenoid valve is controlled 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 mal-
function such as control valve sticking, improper solenoid valve operation.
CONSULT-II Reference ValueUCS002GV
On Board Diagnosis LogicUCS002GW

This is an OBD-II self-diagnostic item.

Diagnostic trouble code “D/C SOLENOID FNCTN” with CONSULT-II or P1764 without 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 5 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 5 is irregular
during releasing accelerator pedal. (Other than during shift change)
Possible CauseUCS002GX

Harness or connectors
(The solenoid and switch circuits are open or shorted.)

Direct clutch solenoid valve

ATF pressure switch 5
DTC Confirmation ProcedureUCS002GY
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 (P1764) is detected, refer to AT-161, "
Diagnostic Procedure" .
If DTC (P1762) is detected, go to AT- 1 5 8 , "
Diagnostic Procedure" .
If DTC (P1845) is detected, go to AT- 1 8 2 , "
Diagnostic Procedure" .
WITH GST
Follow the procedure “With CONSULT-II”.
Item name Condition Display value (Approx)
D/C SOLENOIDDirect clutch disengaged. Refer to AT-2 1
. 0.6 - 0.8 A
Direct clutch engaged. Refer to AT-2 1
. 0 - 0.05 A
ATF PRES SW 5Direct clutch engaged. Refer to AT-2 1
.ON
Direct clutch disengaged. Refer to AT-2 1
.OFF
BCIA0030E

DTC P1764 DIRECT CLUTCH SOLENOID VALVE FUNCTION
AT-161
D
E
F
G
H
I
J
K
L
MA
B
AT
Revision: August 20072004 QX56
Diagnostic ProcedureUCS002GZ
1. CHECK INPUT SIGNALS
With CONSULT-II
1. Turn ignition switch “ON”. (Do not start engine.)
2. Select “SELECTION FROM MENU” in “DATA MONITOR” mode
for “A/T” with CONSULT-II.
3. Start the engine.
4. Drive vehicle in the “D” position (1st

2nd gear), and confirm
the display actuation of the “ATF PRES SW 5” and electrical cur-
rent value of “D/C SOLENOID”.
OK or NG
OK >> GO TO 6.
NG >> GO TO 2.
2. CHECK TCM
Perform TCM input/output signals inspection. Refer to AT-90, "
TCM Input/Output Signal Reference Values" .
OK or NG
OK >> GO TO 3.
NG >> GO TO 5.
3. CHECK DTC
Perform “DTC Confirmation Procedure”.

Refer to AT- 1 6 0 , "DTC Confirmation Procedure" .
OK or NG
OK >>INSPECTION END
NG >> GO TO 4.
4. 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 >> Replace the control valve with TCM. Refer to AT - 2 4 1 , "Control Valve With TCM and A/T Fluid
Temperature Sensor 2" .
NG >> Repair or replace damaged parts.
5. DETECT MALFUNCTIONING ITEM
Check the following items:

Power supply and ground circuit for TCM.

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.
Item name Condition Display value
(Approx)
D/C SOLENOIDDirect clutch disengaged. Refer to AT- 2 1
. 0.6 - 0.8 A
Direct clutch engaged. Refer to AT- 2 1
. 0 - 0.05 A
ATF PRES SW 5Direct clutch engaged. Refer to AT- 2 1
. ON
Direct clutch disengage. Refer to AT-2 1
.OFF
SCIA4797E

AT-164
DTC P1767 HIGH AND LOW REVERSE CLUTCH SOLENOID VALVE
Revision: August 20072004 QX56
Diagnostic ProcedureUCS002H5
1. CHECK INPUT SIGNAL
With CONSULT-II
1. Turn ignition switch “ON”. (Do not start engine.)
2. Select “MAIN SIGNALS” in “DATA MONITOR” mode for “A/T”
with CONSULT-II.
3. Start the engine.
4. Read out the value of “HLR/C SOLENOID” while driving.
OK or NG
OK >> GO TO 6.
NG >> GO TO 2.
2. CHECK TCM
Perform TCM input/output signals inspection. Refer to AT- 9 0 , "
TCM Input/Output Signal Reference Values" .
OK or NG
OK >> GO TO 3.
NG >> GO TO 5.
3. CHECK DTC
Perform “DTC Confirmation Procedure”.

Refer to AT-163, "DTC Confirmation Procedure" .
OK or NG
OK >>INSPECTION END
NG >> GO TO 4.
4. 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 >> Replace the control valve with TCM. Refer to AT-241, "Control Valve With TCM and A/T Fluid
Temperature Sensor 2" .
NG >> Repair or replace damaged parts.
5. DETECT MALFUNCTIONING ITEM
Check the following items:

The A/T assembly harness connector terminals for damage or loose connection with harness connector.

Power supply and ground circuit for TCM.
OK or NG
OK >> GO TO 6.
NG >> Repair or replace damaged parts.
Item name Condition Display value (Approx)
HLR/C SOLHigh and low reverse clutch disengaged.
Refer to AT- 2 1
.0.6 - 0.8 A
High and low reverse clutch engaged.
Refer to AT- 2 1
.0 - 0.05 ASCIA4793E

AT-166
DTC P1769 HIGH AND LOW REVERSE CLUTCH SOLENOID VALVE FUNCTION
Revision: August 20072004 QX56
DTC P1769 HIGH AND LOW REVERSE CLUTCH SOLENOID VALVE FUNCTION
PFP:31940
DescriptionUCS002H6

High and low reverse clutch solenoid valve is controlled 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 mal-
function such as control valve sticking, improper solenoid valve operation.
CONSULT-II Reference ValueUCS002H7
On Board Diagnosis LogicUCS002H8

This is an OBD-II self-diagnostic item.

Diagnostic trouble code “HLR/C SOL FNCTN” with CONSULT-II or P1769 without 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 6 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 6 is irregular
during releasing accelerator pedal. (Other than during shift change)
Possible CauseUCS002H9

Harness or connectors
(The solenoid and switch circuits are open or shorted.)

High and low reverse clutch solenoid valve

ATF pressure switch 6
DTC Confirmation ProcedureUCS002HA
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 (P1769) is detected, refer to AT-167, "
Diagnostic Procedure" .
If DTC (P1767) is detected, go to AT- 1 6 4 , "
Diagnostic Procedure" .
If DTC (P1846) is detected, go to AT- 1 8 5 , "
Diagnostic Procedure" .
Item name Condition Display value (Approx)
HLR/C SOL High and low reverse clutch disengaged. Refer to AT- 2 1
. 0.6 - 0.8 A
High and low reverse clutch engaged. Refer to AT- 2 1
. 0 - 0.05 A
ATF PRES SW 6High and low reverse clutch engaged. Refer to AT- 2 1
.ON
High and low reverse clutch disengaged. Refer to AT- 2 1
. OFF
BCIA0030E

DTC P1769 HIGH AND LOW REVERSE CLUTCH SOLENOID VALVE FUNCTION
AT-167
D
E
F
G
H
I
J
K
L
MA
B
AT
Revision: August 20072004 QX56
WITH GST
Follow the procedure “With CONSULT-II”.
Diagnostic ProcedureUCS002HB
1. CHECK INPUT SIGNALS
With CONSULT-II
1. Turn ignition switch “ON”. (Do not start engine.)
2. Select “SELECTION FROM MENU” in “DATA MONITOR” mode
for “A/T” with CONSULT-II.
3. Start the engine.
4. Drive vehicle in the “D” position (2nd

3rd gear), and confirm
the ON/OFF actuation of the “ATF PRES SW 6” and electrical
current value of “HLR/C SOL”.
OK or NG
OK >> GO TO 6.
NG >> GO TO 2.
2. CHECK TCM
Perform TCM input/output signals inspection. Refer to AT-90, "
TCM Input/Output Signal Reference Values" .
OK or NG
OK >> GO TO 3.
NG >> GO TO 5.
3. CHECK DTC
Perform “DTC Confirmation Procedure”.

Refer to AT- 1 6 6 , "DTC Confirmation Procedure" .
OK or NG
OK >>INSPECTION END
NG >> GO TO 4.
4. 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 >> Replace the control valve with TCM. Refer to AT - 2 4 1 , "Control Valve With TCM and A/T Fluid
Temperature Sensor 2" .
NG >> Repair or replace damaged parts.
Item name Condition Display value
(Approx)
HLR/C SOLHigh and low reverse clutch disengaged. Refer to
AT-2 1
.0.6 - 0.8 A
High and low reverse clutch engaged. Refer to AT-
21 .0 - 0.05 A
ATF PRES
SW 6High and low reverse clutch engaged. Refer to AT-
21 .ON
High and low reverse clutch disengaged. Refer to
AT-2 1
.OFF
SCIA4798E

AT-170
DTC P1772 LOW COAST BRAKE SOLENOID VALVE
Revision: August 20072004 QX56
Diagnostic ProcedureUCS002HH
1. CHECK INPUT SIGNAL
With CONSULT-II
1. Turn ignition switch “ON”. (Do not start engine.)
2. Select “SELECTION FROM MENU” in “DATA MONITOR” mode
for “A/T” with CONSULT-II.
3. Start the engine.
4. Read out the value of “ON OFF SOL” while driving.
OK or NG
OK >> GO TO 6.
NG >> GO TO 2.
2. CHECK TCM
Perform TCM input/output signals inspection. Refer to AT- 9 0 , "
TCM Input/Output Signal Reference Values" .
OK or NG
OK >> GO TO 3.
NG >> GO TO 5.
3. CHECK DTC
Perform “DTC Confirmation Procedure”.

Refer to AT-169, "DTC Confirmation Procedure" .
OK or NG
OK >>INSPECTION END
NG >> GO TO 4.
4. 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 >> Replace the control valve with TCM. Refer to AT-241, "Control Valve With TCM and A/T Fluid
Temperature Sensor 2" .
NG >> Repair or replace damaged parts.
5. DETECT MALFUNCTIONING ITEM
Check the following items:

Power supply and ground circuit for TCM.

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.
Item name Condition Display value (ON-OFF display)
ON OFF SOLLow coast brake engaged.
Refer to AT- 2 1
.ON
Low coast brake disengaged.
Refer to AT- 2 1
.OFFSCIA4794E

AT-172
DTC P1774 LOW COAST BRAKE SOLENOID VALVE FUNCTION
Revision: August 20072004 QX56
DTC P1774 LOW COAST BRAKE SOLENOID VALVE FUNCTIONPFP:31940
DescriptionUCS002HI

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 mal-
function such as control valve sticking, improper solenoid valve operation.
CONSULT-II Reference ValueUCS002HJ
On Board Diagnosis LogicUCS002HK

This is an OBD-II self-diagnostic item.

Diagnostic trouble code “LC/B SOLENOID FNCT” with CONSULT-II or P1774 without 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 CauseUCS002HL

Harness or connectors
(The solenoid and switch circuits are open or shorted.)

Low coast brake solenoid valve

ATF pressure switch 2
DTC Confirmation ProcedureUCS002HM
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-173, "
Diagnostic Pro-
cedure" .
If DTC (P1772) is detected, go to AT-170, "
Diagnostic Proce-
dure" .
WITH GST
Follow the procedure “With CONSULT-II”.
Item name Condition Display value (ON-OFF display)
ON OFF SOLLow coast brake engaged. Refer to AT- 2 1
. ON
Low coast brake disengaged. Refer to AT- 2 1
. OFF
ATF PRES SW 2Low coast brake engaged. Refer to AT- 2 1
. ON
Low coast brake disengaged. Refer to AT- 2 1
. OFF
BCIA0030E