Infiniti F50. Manual — part 81

DTC P1772 LOW COAST BRAKE SOLENOID VALVE

AT-209

D

E

F

G

H

I

J

K

L

M

A

B

AT

4.

CHECK POWER SOURCE CIRCUIT

1.

Turn ignition switch to “OFF” position.

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 5.

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-206, "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

TCM

F103

13 (W/L)

Yes

A/T unit assembly harness
connector

F27

2 (W/L)

SCIA1836E

AT-210

DTC P1772 LOW COAST BRAKE SOLENOID VALVE

Component Inspection

ECS00A36

LOW COAST BRAKE SOLENOID VALVE
Resistance check

1.

Turn ignition switch “OFF”.

2.

Remove oil pan. Refer to

AT-289, "Control Valve Assembly"

.

3.

Disconnect control valve assembly harness connector.

4.

Check resistance between terminal and ground.

5.

If NG, replace control valve assembly. Refer to

AT-289, "Control

Valve Assembly"

.

Operation check

●

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

Solenoid Valve

Connector No.

Terminal No.

(Wire color)

Resistance (

Ω

)

(Approx.)

Low coast brake sole-
noid valve

F301

4 (W) - Ground

20 - 40

Ω

SCIA3093E

SCIA3094E

DTC P1774 LOW COAST BRAKE SOLENOID VALVE FUNCTION

AT-211

D

E

F

G

H

I

J

K

L

M

A

B

AT

DTC P1774 LOW COAST BRAKE SOLENOID VALVE FUNCTION

PFP:31940

Description

ECS00882

●

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.

On Board Diagnosis Logic

ECS00883

●

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

ECS00884

●

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

●

Low coast brake solenoid valve

●

ATF pressure switch 2

DTC Confirmation Procedure

ECS00885

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 to “OFF” position, 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-213, "Diagnostic Pro-

cedure"

.

If DTC (P1772) is detected, go to

AT-208, "Diagnostic Proce-

dure"

.

WITH GST

Follow the procedure “With CONSULT-II”.

SAT014K

AT-212

DTC P1774 LOW COAST BRAKE SOLENOID VALVE FUNCTION

Wiring Diagram — AT — LC/BF

ECS00886

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

TCWM0097E

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 (pressure
switch 2)

–

–

40

Y/G

DATA BIT1

–

–