Infiniti F50. Manual - part 80

DTC P1769 HIGH AND LOW REVERSE CLUTCH SOLENOID VALVE FUNCTION

AT-205

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AT

4. 

CHECK TERMINAL CORD ASSEMBLY

1.

Remove oil pan. Refer to 

AT-289, "Control Valve Assembly"

 .

2.

Disconnect A/T unit assembly harness connector and control valve assembly harness connector.

3.

Check continuity between A/T unit assembly harness connector
and control valve assembly harness connector.

4.

If OK, check harness for short to ground and short to power.

5.

Reinstall any part removed.

OK or NG

OK

>> Replace the control valve assembly. Refer to 

AT-289,

"Control Valve Assembly"

 .

NG

>> Repair open circuit or short to ground or short to power

in harness or connectors.

5. 

CHECK DTC

Perform “DTC Confirmation Procedure”. Refer to 

AT-202, "DTC Confirmation Procedure"

 .

OK or NG

OK

>> INSPECTION END

NG

>> GO TO 6.

6. 

PERFORM TCM INSPECTION

1.

Perform TCM input/output signal inspection.

2.

If NG, recheck TCM pin terminals for damage or loose connection with harness connector.

OK or NG

OK

>> INSPECTION END

NG

>> Repair or replace damaged parts.

Item

Connector No.

Terminal No. (Wire color)

Continuity

A/T unit assembly 
harness connector

F26

4 (Y)

Yes

Control valve assem-
bly harness connec-
tor

F302

11 (Y)

A/T unit assembly 
harness connector

F27

3 (B/W)

Yes

Control valve assem-
bly harness connec-
tor

F301

5 (B/W)

SCIA3091E

AT-206

DTC P1772 LOW COAST BRAKE SOLENOID VALVE

DTC P1772 LOW COAST BRAKE SOLENOID VALVE

PFP:31940

Description

ECS0087W

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.

On Board Diagnosis Logic

ECS0087X

●

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 Cause

ECS0087Y

●

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

●

Low coast brake solenoid valve 

DTC Confirmation Procedure

ECS0087Z

NOTE:
If “DTC Confirmation Procedure” has been previously conducted, always turn ignition switch “OFF”
and wait at least 10 seconds before conducting the next test.
After the repair, perform the following procedure to confirm the malfunction is eliminated.

 WITH CONSULT-II

1.

Turn ignition switch to “ON” position. (Do not start engine.)

2.

Select “DATA MONITOR” mode for “A/T” with CONSULT-II.

3.

Start engine.

4.

Maintain the following conditions for at least 5 consecutive sec-
onds.
Selector lever: “M” position 
Gear position: “M1-1st” or “M2-2nd” gear (LC/B ON/OFF)

5.

If DTC is detected, go to 

AT-208, "Diagnostic Procedure"

 .

 WITH GST

Follow the procedure “With CONSULT-II”.

SAT014K

DTC P1772 LOW COAST BRAKE SOLENOID VALVE

AT-207

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Wiring Diagram — AT — LC/B

ECS00880

TCM terminal and data are reference value. Measured between each terminal and ground.

TCWM0025E

Terminal   

No.

Wire 

color

Item

Condition

Data (Approx.)

13

W/L

Low coast brake 
solenoid valve

When 

vehicle 
cruises

When the solenoid valve is operating (when running in 
M1-1 gear or M2-2 gear)

Battery voltage

When the solenoid valve is not operating (when running in 
“D”)

0V

AT-208

DTC P1772 LOW COAST BRAKE SOLENOID VALVE

Diagnostic Procedure

ECS00881

1. 

CHECK LOW COAST BRAKE SOLENOID VALVE CIRCUIT

1.

Turn ignition switch to “OFF” position.

2.

Disconnect A/T unit assembly harness connector at the trans-
mission right side.

3.

Check the resistance between terminal and ground.

OK or NG

OK >> GO 

TO 

4.

NG

>> GO TO 2.

2. 

CHECK TERMINAL CORD ASSEMBLY

1.

Remove oil pan. Refer to 

AT-289, "Control Valve Assembly"

 .

2.

Disconnect A/T unit assembly harness connector and control valve assembly harness connector.

3.

Check continuity between A/T unit assembly harness connector
and control valve assembly harness connector.

4.

If OK, check harness for short to ground and short to power.

OK or NG

OK

>> GO TO 3.

NG

>> Repair open circuit or short to ground or short to power in harness or connectors.

3. 

CHECK VALVE RESISTANCE

Check valve resistance

●

Refer to 

AT-210, "Component Inspection"

 .

OK or NG

OK >> GO 

TO 

4.

NG

>> Replace the control valve assembly. Refer to 

AT-289, "Control Valve Assembly"

 .

Solenoid valve

Connector No.

Terminal No. 

(Wire color)

Resistance (Approx.)

Low coast brake 
solenoid valve

F27

2 (W/L) - Ground

20 - 40 

Ω

SCIA1835E

Item

Connector No.

Terminal No. (Wire color)

Continuity

A/T unit assembly 
harness connector

F27

2 (B/R)

Yes

Control valve assem-
bly harness connec-
tor

F301

4 (B/R)

SCIA3092E