Infiniti FX35 / FX45. Manual - part 56

AT-152

< SERVICE INFORMATION >

DTC P1772 LOW COAST BRAKE SOLENOID VALVE

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-160

.

OK or NG

OK

>> GO TO 3.

NG

>> Repair or replace damaged parts.

3.

DETECT MALFUNCTIONING ITEM

Check 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-215, "Control Valve with TCM and A/T Fluid Tem-

perature Sensor 2"

.

NG

>> Repair or replace damaged parts.

4.

CHECK DTC

Perform 

AT-151, "DTC Confirmation Procedure"

.

OK or NG

OK

>> INSPECTION END

NG

>> GO TO 2.

DTC P1774 LOW COAST BRAKE SOLENOID VALVE FUNCTION

AT-153

< SERVICE INFORMATION >

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DTC P1774 LOW COAST BRAKE SOLENOID VALVE FUNCTION

Description

INFOID:0000000001327313

• 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-III Reference Value in Data Monitor Mode

INFOID:0000000001327314

On Board Diagnosis Logic

INFOID:0000000001327315

Diagnostic trouble code “P1774 LC/B SOLENOID FNCT” with CONSULT-III or 7th judgement flicker without
CONSULT-III 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 Cause

INFOID:0000000001327316

• Harness or connectors

(Solenoid and switch circuits are open or shorted.)

• Low coast brake solenoid valve 
• ATF pressure switch 2

DTC Confirmation Procedure

INFOID:0000000001327317

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-III

1.

Start engine.

2.

Accelerate vehicle to maintain the following conditions.
MANU MODE SW: ON
GEAR: “1” or “2” (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 “TRANSMISSION” with CONSULT-III. If DTC (P1774) is
detected, go to 

AT-153, "Diagnosis Procedure"

.

If DTC (P1772) is detected, go to 

AT-151, "Diagnosis Procedure"

.

 WITH GST

Follow the procedure “WITH CONSULT-III”.

Diagnosis Procedure

INFOID:0000000001327318

1.

CHECK INPUT SIGNALS

Item name

Condition 

Display value

ON OFF SOL

Low coast brake engaged. Refer to 

AT-18

.

ON

Low coast brake disengaged. Refer to 

AT-18

.

OFF

ATF PRES SW 2

Low coast brake engaged. Refer to 

AT-18

.

ON

Low coast brake disengaged. Refer to 

AT-18

.

OFF

AT-154

< SERVICE INFORMATION >

DTC P1774 LOW COAST BRAKE SOLENOID VALVE FUNCTION

 With CONSULT-III

1.

Start engine.

2.

Select “SELECTION FROM MENU” in “DATA MONITOR” mode for “TRANSMISSION” with CONSULT-III.

3.

Drive vehicle in the manual mode (1st or 2nd 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-160

.

OK or NG

OK

>> GO TO 3.

NG

>> Repair or replace damaged parts.

3.

DETECT MALFUNCTIONING ITEM

Check 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-215, "Control Valve with TCM and A/T Fluid Tem-

perature Sensor 2"

.

NG

>> Repair or replace damaged parts.

4.

CHECK DTC

Perform 

AT-153, "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-18

.

ON

Low coast brake disengaged. Refer to 

AT-18

.

OFF

ATF PRES SW 2

Low coast brake engaged. Refer to 

AT-18

.

ON

Low coast brake disengaged. Refer to 

AT-18

.

OFF

DTC P1815 MANUAL MODE SWITCH

AT-155

< SERVICE INFORMATION >

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DTC P1815 MANUAL MODE SWITCH

Description

INFOID:0000000001327319

Manual mode switch is installed in A/T device. It sends manual mode switch, shift up and shift down switch
signals to TCM.
TCM sends the switch signals to unified meter and A/C amp. by CAN communication line. Then manual mode
switch position is indicated on the A/T indicator. For inspection, refer to 

AT-166

.

CONSULT-III Reference Value in Data Monitor Mode

INFOID:0000000001327320

On Board Diagnosis Logic

INFOID:0000000001327321

Diagnostic trouble code “P1815 MANU MODE SW/CIR” with CONSULT-IIII is detected when TCM monitors
Manual mode, Non manual mode, Up or Down switch signal, and detects as irregular when impossible input
pattern occurs 1 second or more.

Possible Cause

INFOID:0000000001327322

• Harness or connectors

(These switches circuit is open or shorted.)

• Manual mode select switch (Into control device)
• Manual mode position select switch (Into control device)

DTC Confirmation Procedure

INFOID:0000000001327323

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-III

1.

Turn ignition switch ON.

2.

Select “ECU INPUT SIGNALS” in “DATA MONITOR” mode for “TRANSMISSION” with CONSULT-III.

3.

Start engine.

4.

Drive vehicle and maintain the following conditions for at least 2 consecutive seconds.
MANU MODE SW: ON

5.

If DTC is detected, go to 

AT-158, "Diagnosis Procedure"

.

Item name

Condition

Display Value

MANU MODE SW

Manual shift gate position (neutral)

ON

Other than the above

OFF

NON M-MODE SW

Manual shift gate position

OFF

Other than the above

ON

UP SW LEVER

selector lever: + side

ON

Other than the above

OFF

DOWN SW LEVER

selector lever: - side

ON

Other than the above

OFF