Nissan Frontier. Manual - part 1251

P1772 LOW COAST BRAKE SOLENOID

TM-215

< DTC/CIRCUIT DIAGNOSIS >

[5AT: RE5R05A]

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OK or NG

OK

>> GO TO 3.

NG

>> Repair or replace damaged parts.

3.

DETECT MALFUNCTIONING ITEM

Check the following.

• The 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 

TM-288, "Removal and Installation"

.

NG

>> Repair or replace damaged parts.

4.

CHECK DTC

Perform “DTC Confirmation Procedure”.

• Refer to 

TM-214, "DTC Confirmation Procedure"

.

OK or NG

OK

>> INSPECTION END

NG

>> GO TO 2.

TM-216

< DTC/CIRCUIT DIAGNOSIS >

[5AT: RE5R05A]

P1774 LOW COAST BRAKE SOLENOID

P1774 LOW COAST BRAKE SOLENOID

Description

INFOID:0000000009480634

• Low coast brake solenoid valve is turned “ON” or “OFF” by the TCM in response to signals sent from the

transmission range switch, output speed sensor and accelerator pedal position sensor (throttle position sen-

sor). 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 Reference Value in Data Monitor Mode

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On Board Diagnosis Logic

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• This is an OBD-II self-diagnostic item.

• Diagnostic trouble code “P1774” with CONSULT or 7th judgment flicker without CONSULT 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

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• Harness or connectors

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

• Low coast brake solenoid valve 

• ATF pressure switch 2

DTC Confirmation Procedure

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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

1. Start engine.

2. Accelerate vehicle to maintain the following conditions. 

SLCT LVR POSI: “1” or “2” position 

GEAR: “1st” or “2nd” (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. If DTC (P1774) is detected,

refer to 

TM-217, "Diagnosis Procedure"

.

If DTC (P1772) is detected, go to 

TM-214, "Diagnosis Procedure"

.

 WITH GST

Follow the procedure “WITH CONSULT”.

Item name

Condition 

Display value

ON OFF SOL

Low coast brake engaged. Refer to 

TM-133

.

ON

Low coast brake disengaged. Refer to 

TM-133

.

OFF

ATF PRES SW 2

Low coast brake engaged. Refer to 

TM-133

.

ON

Low coast brake disengaged. Refer to 

TM-133

.

OFF

P1774 LOW COAST BRAKE SOLENOID

TM-217

< DTC/CIRCUIT DIAGNOSIS >

[5AT: RE5R05A]

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Diagnosis Procedure

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1.

CHECK INPUT SIGNALS

With CONSULT

1. Start the engine.

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

3. Drive vehicle in the “1” or “2” position (“1

1

” or “2

2

” 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 

TM-218, "Diagnosis Procedure"

.

OK or NG

OK

>> GO TO 3.

NG

>> Repair or replace damaged parts.

3.

DETECT MALFUNCTIONING ITEM

Check the following.

• The 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 

TM-288, "Removal and Installation"

.

NG

>> Repair or replace damaged parts.

4.

CHECK DTC

Perform “DTC Confirmation Procedure”.

• Refer to 

TM-216, "DTC Confirmation Procedure"

.

OK or NG

OK

>> INSPECTION END

NG

>> GO TO 2.

TM-218

< DTC/CIRCUIT DIAGNOSIS >

[5AT: RE5R05A]

MAIN POWER SUPPLY AND GROUND CIRCUIT

MAIN POWER SUPPLY AND GROUND CIRCUIT

Diagnosis Procedure

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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.

3.

DETECT MALFUNCTIONING ITEM

Check the following.

• Harness for short or open between battery and A/T assembly harness connector terminals 1, 2

• Harness for short or open between ignition switch and A/T assembly harness connector terminal 6

• 10A fuse (No. 22, located in the fuse and fusible link block) and 10A fuse (No. 49, located in the IPDM E/R)

• Ignition switch. Refer to 

PG-20, "Wiring Diagram—Ignition Power Supply"

.

OK or NG

OK

>> GO TO 4.

NG

>> Repair or replace damaged parts.

4.

CHECK TCM GROUND CIRCUIT

1. Turn ignition switch OFF.

2. Disconnect A/T assembly harness connector.

Item

Connector

Terminal

Voltage

TCM

F9

1 - Ground

Battery voltage

2 - Ground

6 - Ground

0 V

SCIA2104E

Item

Connector

Terminal

Voltage

TCM

F9

1 - Ground

Battery voltage

2 - Ground

6 - Ground

SCIA2105E