Infiniti M45 (Y34). Manual - part 85

 

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Infiniti M45 (Y34). Manual - part 85

 

 

DTC P1772 LOW COAST BRAKE SOLENOID VALVE

AT-225

D

E

F

G

H

I

J

K

L

M

A

B

AT

Operation Check

Check solenoid valve by listening for its operating sound while
applying battery voltage to the terminal 4 and ground.

SCIA3094E

AT-226

DTC P1774 LOW COAST BRAKE SOLENOID VALVE FUNCTION

DTC P1774 LOW COAST BRAKE SOLENOID VALVE FUNCTION

PFP:31940

Description

ACS004AD

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 Value

ACS004PQ

On Board Diagnosis Logic

ACS004AE

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 Cause

ACS004AF

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

Low coast brake solenoid valve 

ATF pressure switch 2

DTC Confirmation Procedure

ACS004AG

CAUTION:

Always drive vehicle at a safe speed.

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.

Start engine.

2.

Accelerate vehicle to maintain the following condition.
Selector lever: “M” position 
Gear position: “M1-1st” or “M2-2nd” 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-228, "Diagnostic Pro-

cedure"

 .

If DTC (P1772) is detected, go to 

AT-222, "Diagnostic Proce-

dure"

 .

 WITH GST

Follow the procedure “With CONSULT-II”.

Item name

Condition 

Display value

ATF PRES SW 2

Low coast brake solenoid valve operates.

ON

Other conditions

OFF

SAT014K

DTC P1774 LOW COAST BRAKE SOLENOID VALVE FUNCTION

AT-227

D

E

F

G

H

I

J

K

L

M

A

B

AT

Wiring Diagram — AT — LC/BF

ACS004AH

TCWA0134E

AT-228

DTC P1774 LOW COAST BRAKE SOLENOID VALVE FUNCTION

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

Diagnostic Procedure

ACS004AI

1. 

CHECK INPUT SIGNALS

 With CONSULT-II

1.

Start engine.

2.

Select “ECU INPUT SIGNALS” or “MAIN SIGNALS” in “DATA
MONITOR” mode for “A/T” with CONSULT-II.

3.

Accelerate vehicle in the manual mode (“M1-1st” or “M2-2nd”
gear), and confirm the ON/OFF actuation of the “ATF PRES SW
2”.

OK or NG

OK

>> GO TO 4.

NG

>> GO TO 2.

2. 

CHECK HARNESS BETWEEN TCM AND A/T UNIT ASSEMBLY HARNESS CONNECTOR

1.

Turn ignition switch OFF.

2.

Disconnect TCM connector.

3.

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

4.

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

5.

Reinstall any part removed.

OK or NG

OK

>> GO TO 3.

NG

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

in harness or connectors.

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

16

W/G

SEL1 (ATF pres-
sure switch 2)

40

Y/G

DATA BIT1

Item name

Condition 

Display value

ATF PRES SW 2

Low coast brake solenoid 
valve operates.

ON

Other conditions

OFF

PCIA0067E

Item

Connector No.

Terminal No. 

(Wire color)

Continuity

TCM

F103

16 (W/G)

Yes

A/T unit assembly harness 
connector

F26

5 (W/G)

TCM

F104

40 (Y/G)

Yes

A/T unit assembly harness 
connector

F26

2 (Y/G)

TCM

F103

13 (W/L)

Yes

A/T unit assembly harness 
connector

F27

2 (W/L)

SCIA3095E

 

 

 

 

 

 

 

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