GSIC - Global Service Information Center

### DTC P0781 1-2 Shift (1-2 Shift Valve)

## for Preparation Click here

## DESCRIPTION

1. The 1-2 shift valve performs shifting to 1st gear and other gears.

   DTC No. | DTC Detection Condition | Trouble Area

   P0781

   Gear required by the ECM does not match the actual gear when driving (2 trip detection logic)

   1. Valve body is blocked up or stuck (1-2 shift valve)
   2. Automatic transmission (clutch, brake or gear, etc.)

## MONITOR DESCRIPTION

This DTC indicates that the 1-2 shift valve in the valve body is locked in the direction that the spring compresses.
The ECM commands gear shifts by turning the shift solenoid valves ON/OFF and switching oil pressure to the valves in the valve body.
The ECM calculates the actual transmission gear by comparing the signals from the input speed sensor (NT) and the output speed sensor (SP2). The ECM can detect mechanical problems in the shift solenoids, valve body, and the transmission clutches, brakes, and gears. If the ECM detects that the actual gear position and the commanded gear position are different, it will illuminate the MIL and store the DTC.

## INSPECTION PROCEDURE

1.CHECK OTHER DTCS OUTPUT (IN ADDITION TO DTC P0781)

1. Connect the intelligent tester to the DLC3.

1. Turn the ignition switch ON and push the intelligent tester main switch ON.

1. Enter the following menus: Powertrain / Engine and ECT / DTC / Current or Pending.

1. Read the DTCs using the intelligent tester.

   Result:

     Display (DTC output) | Proceed to
     Only P0781 is output | A
     P0781 and other DTCs | B

   HINT:
     If any other codes besides P0781 are output, perform troubleshooting for those DTCs first.

| B |

GO TO DTC CHART

A |

2.PERFORM ACTIVE TEST BY INTELLIGENT TESTER

HINT:

  Performing the intelligent tester's Active Test allows relay, Vacuum Switching Valve (VSV), actuator and other item values to be operated without removing any parts. Performing the Active Test early in troubleshooting is one way to save time. The Data List can be displayed during the Active Test.

1. Warm up the engine.
2. Turn the ignition switch OFF.
3. Connect the intelligent tester to the DLC3.
4. Turn the ignition switch ON and push the tester main switch ON.
5. Enter the following menus: Powertrain / Engine and ECT / Active Test.
6. Follow the instructions on the tester and read the Active Test.

HINT:

  While driving, the shift position can be forcibly changed with the intelligent tester.

  Comparing the shift position commanded by the Active Test with the actual shift position enables you to confirm the problem (Click here).

Item | Test Details | Diagnostic Note

Control the Shift Position

[Test Details]
Operate shift solenoid valve and set each shift position by yourself
[Vehicle Condition]
50 km/h (31 mph) or less
[Other information]

1. Press "→" button: Shift up
2. Press "←" button: Shift down

Possible to check operation of shift solenoid valves

HINT:

1. This test can be conducted when the vehicle speed is 50 km/h (31 mph) or less.
2. The 4th to 5th up-shift must be performed with the accelerator pedal released.
3. The 5th to 4th down-shift must be performed with the accelerator pedal released.
4. Do not operate the accelerator pedal for at least 2 seconds after shifting and do not shift successively.
5. The shift position commanded by the ECM is shown in the Data List (shift status) display on the intelligent tester.

OK:
  Gear position changes in accordance with the tester command.

| NG |

REPAIR OR REPLACE TRANSMISSION VALVE BODY ASSEMBLY

OK |

3.CLEAR DTC AND PERFORM RUNNING TEST

1. Clear the DTC, and check for the DTC again after conducting the "Test Monitor Drive Pattern for ECT" (Click here).

   OK:
     No DTC code

| NG |

REPAIR OR REPLACE TRANSMISSION VALVE BODY ASSEMBLY

OK |

END