2004 INFINITI QX56 ESP

AT-154
DTC P1759 FRONT BRAKE SOLENOID VALVE FUNCTION
Revision: August 20072004 QX56
DTC P1759 FRONT BRAKE SOLENOID VALVE FUNCTIONPFP:31940
DescriptionUCS002G I

Front brake solenoid valve is controlled by the TCM in response to signals sent from the PNP switch, vehi-
cle 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 ValueUCS002GJ
On Board Diagnosis LogicUCS002GK

This is an OBD-II self-diagnostic item.

Diagnostic trouble code “FR/B SOLENOID FNCT” with CONSULT-II or P1759 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 1 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 1 is irregular
during releasing accelerator pedal. (Other than during shift change)
Possible CauseUCS002GL

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

Front brake solenoid valve

ATF pressure switch 1
DTC Confirmation ProcedureUCS002GM
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 (P1759) is detected, refer to AT-155, "
Diagnostic Procedure" .
If DTC (P1757) is detected, go to AT- 1 5 2 , "
Diagnostic Procedure" .
If DTC (P1841) is detected, go to AT- 1 7 6 , "
Diagnostic Procedure" .
Item name Condition Display value (Approx)
FR/B SOLENOIDFront brake engaged. Refer to AT- 2 1
. 0.6 - 0.8 A
Front brake disengaged. Refer to AT- 2 1
. 0 - 0.05 A
ATF PRES SW 1Front brake engaged. Refer to AT- 2 1
.ON
Front brake disengaged. Refer to AT- 2 1
. OFF
BCIA0030E

DTC P1762 DIRECT CLUTCH SOLENOID VALVE
AT-157
D
E
F
G
H
I
J
K
L
MA
B
AT
Revision: August 20072004 QX56
DTC P1762 DIRECT CLUTCH SOLENOID VALVEPFP:31940
DescriptionUCS002GO
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.
CONSULT-II Reference ValueUCS002G P
On Board Diagnosis LogicUCS002GQ

This is an OBD-II self-diagnostic item.

Diagnostic trouble code “D/C SOLENOID/CIRC” with CONSULT-II or P1762 without CONSULT-II 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 CauseUCS002G R

Harness or connectors
(The solenoid circuit is open or shorted.)

Direct clutch solenoid valve
DTC Confirmation ProcedureUCS002G S
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. Turn ignition switch “ON”. (Do not start engine.)
2. Select “DATA MONITOR” mode for “A/T” with CONSULT-II.
3. Start engine.
4. Drive vehicle and maintain the following conditions for at least 5
consecutive seconds.
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.
5. If DTC is detected, go to AT - 1 5 8 , "
Diagnostic Procedure" .
WITH GST
Follow the procedure “With CONSULT-II”.
Item name Condition Display value (Approx) (A)
D/C SOLENOIDDirect clutch disengaged. Refer to AT- 2 1
. 0.6 - 0.8
Direct clutch engaged. Refer to AT- 2 1
.0 - 0.05
BCIA0030E

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 P1767 HIGH AND LOW REVERSE CLUTCH SOLENOID VALVE
AT-163
D
E
F
G
H
I
J
K
L
MA
B
AT
Revision: August 20072004 QX56
DTC P1767 HIGH AND LOW REVERSE CLUTCH SOLENOID VALVEPFP:31940
DescriptionUCS002H0
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.
CONSULT-II Reference ValueUCS002H1
On Board Diagnosis LogicUCS002H2

This is an OBD-II self-diagnostic item.

Diagnostic trouble code “HLR/C SOL/CIRC” with CONSULT-II or P1767 without CONSULT-II 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 CauseUCS002H3

Harness or connectors
(The solenoid circuit is open or shorted.)

High and low reverse clutch solenoid valve
DTC Confirmation ProcedureUCS002H4
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. Turn ignition switch “ON”. (Do not start engine.)
2. Select “DATA MONITOR” mode for “A/T” with CONSULT-II.
3. Start engine.
4. Drive vehicle and maintain the following conditions for at least 5
consecutive seconds.
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.
5. If DTC is detected, go to AT - 1 6 4 , "
Diagnostic Procedure" .
WITH GST
Follow the procedure “With CONSULT-II”.
Item name Condition Display value (Approx) (A)
HLR/C SOLHigh and low reverse clutch disengaged. Refer to AT- 2 1
. 0.6 - 0.8
High and low reverse clutch engaged. Refer to AT- 2 1
. 0 - 0.05
BCIA0030E

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 P1772 LOW COAST BRAKE SOLENOID VALVE
AT-169
D
E
F
G
H
I
J
K
L
MA
B
AT
Revision: August 20072004 QX56
DTC P1772 LOW COAST BRAKE SOLENOID VALVEPFP:31940
DescriptionUCS002H C
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.
CONSULT-II Reference ValueUCS002H D
On Board Diagnosis LogicUCS002HE

This is an OBD-II self-diagnostic item.

Diagnostic trouble code “LC/B SOLENOID/CIRC” with CONSULT-II or P1772 without CONSULT-II is
detected when TCM detects an improper voltage drop when it tries to operate the solenoid valve.
Possible CauseUCS002HF

Harness or connectors
(The solenoid circuit is open or shorted.)

Low coast brake solenoid valve
DTC Confirmation ProcedureUCS002HG
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. Turn ignition switch “ON”. (Do not start engine.)
2. Select “DATA MONITOR” mode for “ENGINE” with CONSULT-II.
3. Start engine.
4. Drive vehicle and maintain the following conditions for at least 5
consecutive seconds.
Selector lever: “1” or “2”
Gear position: “1st” or “2nd” gear (LC/B ON/OFF)
5. If DTC is detected, go to AT - 1 7 0 , "
Diagnostic Procedure" .
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
BCIA0030E

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

AT-236
A/T SHIFT LOCK SYSTEM
Revision: August 20072004 QX56
A/T SHIFT LOCK SYSTEMPFP:34950
DescriptionUCS002J 6

The electrical key interlock mechanism also operates as a shift lock:
With the ignition switch turned to ON, the selector lever cannot be shifted from “P” (parking) to any other
position unless the brake pedal is depressed.
With the key removed, the selector lever cannot be shifted from “P” to any other position.
The key cannot be removed unless the selector lever is placed in “P”.

The shift lock and key interlock mechanisms are controlled by the ON-OFF operation of the shift lock sole-
noid and by the operation of the rotator and slider located inside the key cylinder, respectively.
Shift Lock System Electrical Parts LocationUCS002J 7
LCIA0326E