Dtc P0778 Pressure Control Solenoid B Electrical (Shift Solenoid Valve Sl2)

Transmission. Lexus Gs430, Gs300. Uzs190 Grs190
A760E Automatic Transmission. Lexus Gs430, Gs300. Uzs190 Grs190

DESCRIPTION

MONITOR DESCRIPTION

WIRING DIAGRAM

INSPECTION PROCEDURE

INSPECT TRANSMISSION WIRE (SL2)

CHECK HARNESS AND CONNECTOR (TRANSMISSION WIRE - ECM)

INSPECT SHIFT SOLENOID SL2

DTC P0778 Pressure Control Solenoid "B" Electrical (Shift Solenoid Valve SL2)


DESCRIPTION

Shifting from 1st to 6th is performed in combination with "ON" and "OFF" operation of the shift solenoid valves SL1, SL2, S1, S2, S3, S4 and SR which is controlled by the ECM. If an open or short circuit occurs in either of the shift solenoid valves, the ECM controls the remaining normal shift solenoid valve to allow the vehicle to be operated smoothly (Click here).

DTC No.
DTC Detection Condition
Trouble Area
P0778
The ECM checks for an open or short in the shift solenoid valve SL2 circuit while driving and shifting gears. (1-trip detection logic)
  1. Output signal duty equals to 100%.
    (NOTE: SL2 output signal duty is less than 100% under normal condition.)
  1. Open or short in shift solenoid valve SL2 circuit
  2. Shift solenoid valve SL2
  3. ECM

MONITOR DESCRIPTION

This DTC indicates an open or short in the shift solenoid valve SL2 circuit. The ECM commands gear shifts by turning the shift solenoid valves "ON/OFF". When there is an open or short circuit in any shift solenoid valve circuit, the ECM detects the problem and illuminates the MIL and stores the DTC. And the ECM performs the fail-safe function and turns the other shift solenoid valves in good condition "ON/OFF". (In case of an open or short circuit, the ECM stops sending current to the circuit.)
While driving and shifting gears, if the ECM detects an open or short in the shift solenoid valve SL2 circuit, the ECM determines there is a malfunction (Click here).

WIRING DIAGRAM


Lexus Gs430, Gs300. Uzs190 Grs190.A760E Automatic Transmission.Electronic Controlled Automatic Transmission System.
Dtc
  P0778  Pressure Control Solenoid B Electrical (Shift Solenoid Valve Sl2)


INSPECTION PROCEDURE

HINT:
  1. The shift solenoid valve SL2 is turned on/off normally when the shift lever is in the D position:

    ECM command gearshift
    1st
    2nd
    3rd
    4th
    5th
    6th
    Shift solenoid valve SL2
    ON
    ON
    ON
    ON
    OFF
    OFF
1.INSPECT TRANSMISSION WIRE (SL2)


    Lexus Gs430, Gs300. Uzs190 Grs190.A760E Automatic Transmission.Electronic Controlled Automatic Transmission System.
Dtc
  P0778  Pressure Control Solenoid B Electrical (Shift Solenoid Valve Sl2)
  1. Disconnect the transmission wire connector from the transmission.

  1. Measure the resistance according to the value(s) in the table below.

    Resistance:
    Tester Connection
    Specified Condition
    20°C (68°F)
    10 (SL2+) - 2 (SL2-)
    5.0 to 5.6 Ω
  1. Measure the resistance according to the value(s) in the table below.

    Resistance (Check for short):
    Tester Connection
    Specified Condition
    10 (SL2+) - Body ground
    10 kΩ or higher
    2 (SL2-) - Body ground



NG
Go to step 3
OK


2.CHECK HARNESS AND CONNECTOR (TRANSMISSION WIRE - ECM)


    Lexus Gs430, Gs300. Uzs190 Grs190.A760E Automatic Transmission.Electronic Controlled Automatic Transmission System.
Dtc
  P0778  Pressure Control Solenoid B Electrical (Shift Solenoid Valve Sl2)
  1. Connect the transmission connector to the transmission.

  1. Disconnect the connector from the ECM.

  1. Measure the resistance according to the value(s) in the table below.

    Resistance:
    Tester Connection
    Specified Condition
    20°C (68°F)
    E7 - 11 (SL2+) - E7 - 10 (SL2-)
    5.0 to 5.6 Ω
  1. Measure the resistance according to the value(s) in the table below.

    Resistance (Check for short):
    Tester Connection
    Specified Condition
    E7 - 11 (SL2+) - Body ground
    10 kΩ or higher
    E7 - 10 (SL2-) - Body ground



NG
REPAIR OR REPLACE HARNESS OR CONNECTOR
OK

REPLACE ECM

3.INSPECT SHIFT SOLENOID SL2


    Lexus Gs430, Gs300. Uzs190 Grs190.A760E Automatic Transmission.Electronic Controlled Automatic Transmission System.
Dtc
  P0778  Pressure Control Solenoid B Electrical (Shift Solenoid Valve Sl2)
  1. Remove the shift solenoid valve SL2.

  1. Measure the resistance according to the value(s) in the table below.

    Resistance:
    Tester Connection
    Specified Condition
    20°C (68°F)
    1 - 2
    5.0 to 5.6 Ω
  1. Connect the positive (+) lead with a 21 W bulb to terminal 2 and the negative (-) lead to terminal 1 of the solenoid valve connector, then check the movement of the valve.

    OK:
    The solenoid makes an operating sound.


NG
REPLACE SHIFT SOLENOID SL2
OK

REPAIR OR REPLACE TRANSMISSION WIRE