Lexus RX (RX 350L, RX450h) 2016-2024 Repair Manual: Pressure Control Solenoid "B" Circuit Open (P077513)

Lexus RX (RX 350L, RX450h) 2016-2024 Repair Manual / Drivetrain / U881e (automatic Transmission / Transaxle) / Automatic Transaxle System / Pressure Control Solenoid "B" Circuit Open (P077513)

DESCRIPTION

Changing gears is performed by the ECM turning the shift solenoid valves SL1, SL2, SL3, SL4 and SL5 on and off.

If an open or short occurs in any of the shift solenoid valve circuits, the ECM controls the remaining normal shift solenoid valves to allow the vehicle to be driven. If all of the shift solenoid valves are malfunctioning, only the mechanical fluid pressure circuit will function and some manual operation will be possible. If an open or short occurs in a shift solenoid valve circuit, the ECM cuts power to the malfunctioning shift solenoid valve.

HINT:

The following table shows normal operation of the shift solenoid valves SL2 when the shift lever is in D.

Shift Solenoid Valve Operation:

Gear

1st

2nd

3rd

4th

5th

6th

7th

8th

Shift Solenoid Valve SL2

OFF

OFF

OFF

OFF

ON

ON

ON

ON

DTC No.

Detection Item

DTC Detection Condition

Trouble Area

MIL

Memory

Note

P077513

Pressure Control Solenoid "B" Circuit Open

1. Diagnosis Condition 2. Malfunction Status 3. Malfunction Time 4. Other

  • Driving so that gear changes occur
  • Shift solenoid valve SL2 circuit is open or shorted
  • 1 second
  • 1-trip detection logic
  • Shift solenoid valve SL2
  • Transmission wire
  • Harness and connector
  • ECM

Comes on

DTC stored

SAE Code:

P0778

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 or off. When there is an open or short in any shift solenoid valve circuit, the ECM detects the problem, illuminates the MIL and stores a DTC.

The ECM performs the fail-safe function and turns the other normal shift solenoid valves on or off. In the case of an open or short circuit, the ECM stops sending current to the open or shorted solenoid.

MONITOR STRATEGY

Related DTCs

P0778: Shift solenoid valve SL2/Range check

Required sensors/Components

Shift solenoid valve SL2

Frequency of operation

Continuous

Duration

1 sec.

MIL operation

Immediate

Sequence of operation

None

TYPICAL ENABLING CONDITIONS

All

The monitor will run whenever the following DTCs are not present

None

Solenoid current cut status

Not cut

Engine switch

On (IG)

Starter

OFF
Condition (A)

Battery voltage

12 V or more
Condition (B)

Battery voltage

10 V or more and less than 12 V

Target current

Less than 0.75 A
Condition (C)

Battery voltage

8 V or more

Target current

0.25 A or more

TYPICAL MALFUNCTION THRESHOLDS

When one of the following conditions is met: Condition (A), (B) or (C)

Condition (A) and (B)

Output duty cycle

100% or more
Condition (C)

Output duty cycle

0% or less

COMPONENT OPERATING RANGE

Output duty cycle

More than 3% and less than 100%

CONFIRMATION DRIVING PATTERN

CAUTION:

When performing the confirmation driving pattern, obey all speed limits and traffic laws.

HINT:

  • After repairs have been completed, clear the DTCs and then check that the vehicle has returned to normal by performing the following All Readiness check procedure.
  • When clearing the permanent DTCs, refer to the Clear Permanent DTC procedure.

    Click here

  1. Connect the Techstream to the DLC3.
  2. Turn the engine switch on (IG) and turn the Techstream on.
  3. Clear the DTCs (even if no DTCs are stored, perform the clear DTC procedure).
  4. Turn the engine switch off and wait for 2 minutes or more.
  5. Turn the engine switch on (IG) and turn the Techstream on.
  6. Start the engine.
  7. Perform the D Position Shift Test inspection in Road Test. [*1]

    Click here

    HINT:

    [*1] : Normal judgment procedure.

    The normal judgment procedure is used to complete DTC judgment and also used when clearing permanent DTCs.

  8. Enter the following menus: Powertrain / Transmission / Utility / All Readiness.
  9. Input the DTC: P077513.
  10. Check the DTC judgment result.

    Techstream Display

    Description

    NORMAL
    • DTC judgment completed
    • System normal

    ABNORMAL
    • DTC judgment completed
    • System abnormal

    INCOMPLETE
    • DTC judgment not completed
    • Perform driving pattern after confirming DTC enabling conditions

    N/A
    • Unable to perform DTC judgment
    • Number of DTCs which do not fulfill DTC preconditions has reached ECU memory limit

    HINT:

    • If the judgment result shows NORMAL, the system is normal.
    • If the judgment result shows ABNORMAL, the system has a malfunction.
    • If the judgment result shows INCOMPLETE or N/A, perform the normal judgment procedure again.

WIRING DIAGRAM

CAUTION / NOTICE / HINT

NOTICE:

  • Perform the universal trip to clear permanent DTCs.

    Click here

  • Perform registration and/or initialization when parts related to the automatic transaxle are replaced.

    Click here

PROCEDURE

1.

CHECK HARNESS AND TRANSMISSION WIRE (TRANSMISSION WIRE (SHIFT SOLENOID VALVE SL2 - ECM)

(a) Disconnect the D2 ECM connector.

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

Standard Resistance:

Tester Connection

Condition

Specified Condition

D2-6 (SL2+) - D2-7 (SL2-)

20°C (68°F)

5.0 to 5.6 Ω

D2-6 (SL2+) or D2-7 (SL2-) - Body ground and other terminals

Always

10 kΩ or higher
NG

GO TO STEP 3

OK

2.

REPLACE ECM

(a) Replace the ECM.

Click here

NEXT

PERFORM A/T CODE REGISTRATION

3.

CHECK HARNESS AND CONNECTOR (TRANSMISSION WIRE - ECM)

(a) Disconnect the D56 transmission wire connector.

(b) Disconnect the D2 ECM connector.

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

Standard Resistance:

Tester Connection

Condition

Specified Condition

D56-28 (SL2+) - D2-6 (SL2+)

Always

Below 1 Ω

D56-29 (SL2-) - D2-7 (SL2-)

Always

Below 1 Ω

D56-28 (SL2+) or D2-6 (SL2+) - Body ground and other terminals

Always

10 kΩ or higher

D56-29 (SL2-) or D2-7 (SL2-) - Body ground and other terminals

Always

10 kΩ or higher
NG

REPAIR OR REPLACE HARNESS OR CONNECTOR (TRANSMISSION WIRE - ECM)
OK

4.

INSPECT SHIFT SOLENOID VALVE SL2

(a) Remove the shift solenoid valve SL2.

Click here

*a

Component without harness connected

(Shift Solenoid Valve SL2)

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

Standard Resistance:

Tester Connection

Condition

Specified Condition

Shift solenoid valve SL2 connector terminal 1 - terminal 2

20°C (68°F)

5.0 to 5.6 Ω

(c) Connect a positive (+) lead from the battery to terminal 1 and a negative (-) lead with a 21 W bulb to terminal 2 of the solenoid valve connector. Check that the valve moves and makes an operating sound.

OK:

Valve moves and makes an operating sound.

OK

REPAIR OR REPLACE TRANSMISSION WIRE

NG

REPLACE SHIFT SOLENOID VALVE SL2

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