AUTOMATIC TRANSMISSION SYSTEM, Diagnostic DTC:P0756

DTC Code DTC Name
P0756 Shift Solenoid "B" Performance (Shift Solenoid Valve S2)

SYSTEM DESCRIPTION

The ECM uses signals from the transmission revolution sensor (SP2) and transmission revolution sensor (NT) to detect the actual gear position (1st, 2nd, 3rd, 4th, 5th or 6th gear).

Then the ECM compares the actual gear with the shift schedule in the ECM memory to detect mechanical problems of the shift solenoid valves, valve body or automatic transmission (clutch, brake or gear, etc.).

DTC No. Detection Item DTC Detection Condition Trouble Area MIL Memory
P0756 Shift Solenoid "B" Performance (Shift Solenoid Valve S2)

[S2 stuck ON malfunction*1:]

Shifting to 3rd and 5th gears is impossible.

The ECM determines there is a malfunction when the following conditions are both met. (2-trip detection logic)


  • (a) When the ECM directs the gearshift to change to 5th gear, the actual gear is shifted to 6th.

  • (b) When the ECM directs the gearshift to change to 6th gear, the actual gear is shifted to 6th.

[S2 stuck OFF malfunction*2:]

The vehicle starts in 3rd gear and shifting to 6th gear is impossible.

The ECM determines there is a malfunction when the following conditions are both met. (2-trip detection logic)


  • (a) When the ECM directs the gearshift to change to 1st gear, the actual gear is shifted to 3rd.

  • (b) When the ECM directs the gearshift to change to 6th gear, the actual gear is shifted to 5th.

[S2 stuck ON malfunction*1:]


  • Shift solenoid valve S2 remains open

  • Valve body is blocked

  • Automatic transmission (clutch, brake or gear, etc.)

[S2 stuck OFF malfunction*2:]


  • Shift solenoid valve S2 remains closed

  • Valve body is blocked

  • Automatic transmission (clutch, brake or gear, etc.)

 Comes on DTC stored

Tech Tips


  • Gear positions in the event of a solenoid valve mechanical problem:

    ECM commanded gear 1st 2nd 3rd 4th 5th 6th
    *1: Actual gear position under S2 stuck ON malfunction 1st 2nd 2nd 4th 6th 6th
    *2: Actual gear position under S2 stuck OFF malfunction 3rd 3rd 3rd 4th 5th 5th

MONITOR DESCRIPTION

This DTC indicates "stuck ON malfunction" or "stuck OFF malfunction" of the shift solenoid valve S2.

The ECM commands gear shifts by turning the shift solenoid valves "ON/OFF". When the gear position commanded by the ECM and the actual gear position are not the same, the ECM illuminates the MIL and stores the DTC.

CAUTION / NOTICE / HINT

Note

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

Click here


  1. ACTIVE TEST

    Tech Tips

    Using the GTS to perform Active Test allows relays, VSVs, actuators and other items to be operated without removing any parts. This non-intrusive functional inspection can be very useful because intermittent operation may be discovered before parts or wiring is disturbed. Performing Active Test early in troubleshooting is one way to save diagnostic time. Data List information can be displayed while performing Active Test.


    1. Warm up the engine.

    2. Turn the engine switch off.

    3. Connect the GTS to the DLC3.

    4. Turn the engine switch on (IG).

    5. Turn the GTS on.

    6. Enter the following menus: Powertrain / Engine and ECT / Active Test / Control the Shift Position.

    7. According to the display on the GTS, perform the "Active Test".

      Tech Tips

      While driving, the shift position can be forcibly changed with the GTS. Comparing the shift position commanded by the Active Test with the actual shift position enables you to confirm the problem.

      Click here


      Powertrain > Engine > Active Test
      Tester Display Measurement Item Control Range Diagnostic Note
      Control the Shift Position Operate shift solenoid valves and set each shift position

      • Press "→" button: Shift up

      • Press "←" button: Shift down

      Possible to check operation of the shift solenoid valves.

      [Vehicle Condition]

      50 km/h (30 mph) or less

      Powertrain > Engine > Active Test
      Tester Display
      Control the Shift Position

      Tech Tips


      • This test can be conducted when the vehicle speed is 50 km/h (31 mph) or less.

      • The 4th to 5th and 5th to 6th up-shifts must be performed with the accelerator pedal released.

      • The 6th to 5th and 5th to 4th down-shifts must be performed with the accelerator pedal released.

      • Do not operate the accelerator pedal for at least 2 seconds after shifting and do not shift successively.

      • The shift position commanded by the ECM is shown in the Data List (Shift Status) display on the GTS.

      • The shift solenoid valve S2 is turned on/off normally when the shift lever is in the D position:

        ECM commanded gear 1st 2nd 3rd 4th 5th 6th
        Shift solenoid valve S2 ON ON OFF OFF OFF ON

PROCEDURE


  1. CHECK OTHER DTCS OUTPUT


    1. Connect the GTS to the DLC3.

    2. Turn the engine switch on (IG).

    3. Enter the following menus: Powertrain / Engine and ECT / Trouble Codes.


      Powertrain > Engine > Trouble Codes

    4. Read the DTCs using the GTS.

      Result
      Result Proceed to
      Only DTC P0756 is output A
      P0756 and other DTCs are output B

      Tech Tips

      If any DTCs other than P0756 are output, perform troubleshooting for those DTCs first.


    B

    GO TO DTC CHART Click here

    A

  2. INSPECT SHIFT SOLENOID VALVE S2


    1. A01MVNQC05
      *a Shift Solenoid Valve S2

      Remove the shift solenoid valve S2.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      Solenoid Connector (S2) - Solenoid Body (S2) 20°C (68°F) 11 to 15 Ω

    3. Connect the positive (+) lead to the terminal of the solenoid connector, and the negative (-) lead to the solenoid body.

      OK
      The solenoid makes an operating sound.
      Result
      Proceed to
      OK
      NG

    NG

    REPLACE SHIFT SOLENOID VALVE S2 Click here

    OK

  3. INSPECT TRANSMISSION VALVE BODY ASSEMBLY


    1. Check the transmission valve body assembly.

      Click here

      OK
      There is no foreign matter on each valve and they operate smoothly.
      Result
      Proceed to
      OK
      NG

    OK

    REPAIR OR REPLACE AUTOMATIC TRANSMISSION ASSEMBLY Click here

    NG

    REPAIR OR REPLACE TRANSMISSION VALVE BODY ASSEMBLY Click here