2004 INFINITI QX56 turn signal

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

DTC P1774 LOW COAST BRAKE SOLENOID VALVE FUNCTION
AT-173
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Revision: August 20072004 QX56
Diagnostic ProcedureUCS002H N
1. CHECK INPUT SIGNALS
With CONSULT-II
1. Turn ignition switch “ON”. (Do not start engine.)
2. Select “SELECTION FORM MENU” in “DATA MONITOR” mode
for “A/T” with CONSULT-II.
3. Start the engine.
4. Drive vehicle in the manual mode (“M1-1st” or “M2-2nd” gear),
and confirm the ON/OFF actuation of the “ATF PRES SW 2” and
“ON OFF 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 7 2 , "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
(ON-OFF dis-
play)
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
SCIA4794E

CLOSED THROTTLE POSITION AND WIDE OPEN THROTTLE POSITION CIR-
CUIT
AT-187
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Revision: August 20072004 QX56
CLOSED THROTTLE POSITION AND WIDE OPEN THROTTLE POSITION CIR-
CUIT
PFP:18002
CONSULT-II Reference ValueUCS002IC
Diagnostic ProcedureUCS002ID
1. CHECK CAN COMMUNICATION LINE
Perform the self-diagnosis. Refer to AT - 9 3 , "
SELF-DIAGNOSTIC RESULT MODE" .
Is a malfunction in the CAN communication indicated in the results?
YES >> Check CAN communication line. Refer to AT- 1 0 3 , "DTC U1000 CAN COMMUNICATION LINE" .
NO >> GO TO 2.
2. CHECK THROTTLE POSITION SIGNAL CIRCUIT
With CONSULT-II
1. Turn ignition switch “ON”. (Do not start engine.)
2. Select “ECU INPUT SIGNALS” in “DATA MONITOR” mode for
“A/T” with CONSULT-II.
3. Depress accelerator pedal and read out the value of “CLSD THL
POS” and “W/O THL POS”.
OK or NG
OK >>INSPECTION END
NG >> Check the following items. If NG, repair or replace damaged parts.

Perform the self-diagnosis for “ENGINE” with CONSULT-II.

Open circuit or short to ground or short to power in harness or connectors.

Pin terminals for damage or loose connection with harness connector.
Item name Condition Display value
CLSD THL POSReleased accelerator pedal. ON
Fully depressed accelerator pedal. OFF
W/O THL POSFully depressed accelerator pedal. ON
Released accelerator pedal. OFF
Accelerator Pedal OperationMonitor Item
CLSD THL POS W/O THL POS
Released ON OFF
Fully depressed OFF ON
PCIA0070E

AT-188
BRAKE SIGNAL CIRCUIT
Revision: August 20072004 QX56
BRAKE SIGNAL CIRCUITPFP:25320
CONSULT-II Reference ValueUCS002IE
Diagnostic ProcedureUCS002IF
1. CHECK CAN COMMUNICATION LINE
Perform the self-diagnosis. Refer to AT-93, "
SELF-DIAGNOSTIC RESULT MODE" .
Is a malfunction in the CAN communication indicated in the results?
YES >> Check CAN communication line. Refer to AT-103, "DTC U1000 CAN COMMUNICATION LINE" .
NO >> GO TO 2.
2. CHECK STOP LAMP SWITCH CIRCUIT
With CONSULT-II
1. Turn ignition switch “ON”. (Do not start engine.)
2. Select “ECU INPUT SIGNALS” in “DATA MONITOR” mode for
“A/T” with CONSULT-II.
3. Read out ON/OFF switching action of the “BRAKE SW”.
OK or NG
OK >>INSPECTION END
NG >> GO TO 3.
3. CHECK STOP LAMP SWITCH
Check continuity between stop lamp switch harness connector termi-
nals 3 and 4.
Check stop lamp switch after adjusting brake pedal — refer to
BR-6, "
BRAKE PEDAL" .
OK or NG
OK >>INSPECTION END
NG >> Check the following items. If NG, repair or replace dam-
aged parts.

Harness for short or open between battery and stop lamp switch.

Harness for short or open between stop lamp switch and combination meter.
Item name Condition Display value
BRAKE SWDepressed brake pedal. ON
Released brake pedal. OFF
PCIA0070E
Condition Continuity
When brake pedal is depressed Yes
When brake pedal is released No
SCIA2126E

TOW MODE SWITCH
AT-189
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Revision: August 20072004 QX56
TOW MODE SWITCHPFP:25129
DescriptionUCS002IG
When tow mode switch is “ON”, tow mode switch signals are sent to TCM from combination meter by CAN
communication line.Then it`s a tow mode condition.
Diagnostic ProcedureUCS002IH
1. CHECK CAN COMMUNICATION LINE
Perform the self-diagnosis. Refer to AT - 9 3 , "
SELF-DIAGNOSTIC RESULT MODE" .
Is any malfunction in the CAN communication indicated in the results?
YES >> Check CAN communication line. Refer to AT- 1 0 3 , "DTC U1000 CAN COMMUNICATION LINE" .
NO >> GO TO 2.
2. CHECK POWER SOURCE
1. Turn ignition switch “ON”. (Do not start engine.)
2. Check the voltage between tow mode switch connector terminal
1 and ground.
OK or NG
OK >>INSPECTION END
NG >> GO TO 3.
3. CHECK TOW MODE SWITCH
1. Turn ignition switch “OFF”.
2. Disconnect tow mode switch connector.
3. Check continuity between tow mode switch connector M254 ter-
minals 1 and 2.
OK or NG
OK >> GO TO 4.
NG >> Repair or replace tow mode switch.
4. DETECT MALFUNCTIONING ITEM
Check the following items. If any items are damaged, repair or replace damaged parts.

Harness for short or open between combination meter connector terminal 35 and tow mode switch con-
nector terminal 1.

Harness for short or open between tow mode switch connector terminal 2 and ground.
OK or NG
OK >> GO TO 5.
NG >> Repair or replace damaged parts.
ConditionTo w m o d e
switchData (Approx.)
When ignition switch is turned to “ON”ON 0V
OFF Battery voltage
SCIA5156E
Condition Continuity
To w m o d e s w i t c h “ O N ” Ye s
To w m o d e s w i t c h “ O F F ” N o
SCIA5157E

AT-222
TROUBLE DIAGNOSIS FOR SYMPTOMS
Revision: August 20072004 QX56
2. CHECK 4TH POSITION SWITCH CIRCUIT
With CONSULT-II
1. Turn ignition switch “ON”.
2. Select "ECU INPUT SIGNALS" in "DATA MONITOR" mode for
"A/T" with CONSULT-II.
3. Read out "OD CONT SW" switch moving selector lever to each
position.
Without CONSULT-II
1. Turn ignition switch “ON”. (Do not start engine)
2. Check voltage between A/T device harness connector terminal
and ground.
OK or NG
OK >> GO TO 3.
NG >> Repair or replace damaged parts.
3. CHECK A/T FLUID LEVEL
Check the A/T fluid level again. Refer to AT- 1 3 , "
Checking A/T Fluid"
.
OK or NG
OK >> GO TO 4.
NG >> Refill ATF.
Monitor item Condition Display value
OD CONT SWWhen setting the selector
lever to "4" and "3" posi-
tion.ON
When setting selector
lever to other positions.OFF
LCIA0339E
Item Connector No.Te r m i n a l N o .
(Wire color)ConditionData
(Approx.)
4th position
switchM2031 (SB) -
GroundWhen setting
the selector
lever to "4"
and "3" posi-
tion.0V
When setting
selector lever
to other posi-
tions.Battery volt-
age
LCIA0340E
SAT6 3 8A

AT-228
TROUBLE DIAGNOSIS FOR SYMPTOMS
Revision: August 20072004 QX56
2. CHECK 1ST POSITION SWITCH CIRCUIT
With CONSULT-II
1. Turn ignition switch “ON”.
2. Select "ECU INPUT SIGNALS" in "DATA MONITOR" mode for
"A/T" with CONSULT-II.
3. Read out "1 POSITION SW" switch moving selector lever to
each position.
Without CONSULT-II
1. Turn ignition switch “ON”. (Do not start engine)
2. Check voltage between A/T device harness connector terminal
and ground.
OK or NG
OK >> GO TO 3.
NG >> Repair or replace damaged parts.
3. CHECK A/T FLUID LEVEL
Check the A/T fluid level again. Refer to AT- 1 3 , "
Checking A/T Fluid"
.
OK or NG
OK >> GO TO 4.
NG >> Refill ATF.
Monitor item Condition Display value
1 POSITION SWWhen setting the selector
lever to "1" position.ON
When setting selector
lever to other positions.OFF
LCIA0339E
Item Connector No.Te r m i n a l N o .
(Wire color)ConditionData
(Approx.)
1st position
switchM2037 (Y/G) -
GroundWhen setting
the selector
lever to "1"
position.0V
When setting
selector lever
to other posi-
tions.Battery volt-
age
LCIA0341E
SAT6 3 8A