AUTOMATIC TRANSAXLE SYSTEM, Diagnostic DTC:P07957F

DTC Code DTC Name
P07957F Pressure Control Solenoid "C" Actuator Stuck Off

SYSTEM DESCRIPTION

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

The ECM compares the actual gear with the shift schedule in the ECM memory to detect mechanical malfunctions of the solenoid valves and transmission valve body assembly.

DTC No. Detection Item DTC Detection Condition Trouble Area MIL Memory Note
P07957F Pressure Control Solenoid "C" Actuator Stuck Off

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


    DTC Detection Condition 1:

  1. ATF temperature is -10°C (14°F) or higher, and the vehicle is being driven with the shift lever in D (no malfunctions are detected in the solenoid (SL1, SL2, SL3 and SL4) valves, transmission revolution sensor (NT, NC), coolant temperature sensor, oil temperature sensor, knock control sensor, electronic throttle or CAN communication between engine control unit and transmission control unit)

  2. Both of the following conditions (a) and (b) are met:


    1. When the ECM commands the transaxle to shift to 2nd gear, the actual gear changes to 1st.

    2. When the ECM commands the transaxle to shift to 6th gear, the engine overruns.

  3. 0.5 seconds

  4. 2-trip detection logic


    DTC Detection Condition 2:

  1. ATF temperature is -10°C (14°F) or higher, and the vehicle is being driven with the shift lever in D (no malfunctions are detected in the solenoid (SL1, SL2, SL3 and SL4) valves, transmission revolution sensor (NT, NC), coolant temperature sensor, oil temperature sensor, knock control sensor, electronic throttle or CAN communication between engine control unit and transmission control unit)

  2. When the ECM commands the transaxle to shift to 1st gear, the actual gear changes to 2nd.

  3. 0.8 seconds

  4. 2-trip detection logic

  • Solenoid (SL3) valve remains open or closed.

  • Transmission valve body assembly is blocked.

  • Automatic transaxle assembly (clutch, brake, gear, etc.)

 Comes on DTC stored

SAE Code:

P0796

MONITOR DESCRIPTION

The ECM commands gear shifts by turning the solenoid valves on and off. According to the input shaft revolution (speed), intermediate (counter) shaft revolution (speed) and output shaft revolution (speed), the ECM detects the actual gear (1st, 2nd, 3rd, 4th, 5th or 6th gear). When the gear commanded by the ECM and the actual gear are not the same, the ECM illuminates the MIL and stores a DTC.

CAUTION / NOTICE / HINT

Note

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

Click here

Tech Tips

After performing repair, clear the DTCs and perform the following procedure to check that DTCs are not output.


  1. Perform the D Position Shift Test inspection in Road Test.

    Click here

  2. Turn the engine switch off.

  3. Perform step (1) again.

  4. Check for DTCs again.

    Click here

PROCEDURE


  1. CHECK OTHER DTCS OUTPUT (IN ADDITION TO DTC P07957F)


    1. Connect the GTS to the DLC3.

    2. Turn the engine switch on (IG).

    3. Turn the GTS on.

    4. Enter the following menus: Powertrain / Transmission / Trouble Codes.


      Powertrain > Transmission > Trouble Codes

    5. Read the DTCs using the GTS.

      Result
      Result Proceed to
      Only DTC P07957F is output A
      DTC P07957F and other DTCs are output B

      Tech Tips

      If a solenoid valve is stuck OFF, DTCs for several solenoid valves including the malfunctioning solenoid valve will be stored.


    B

    PERFORM ACTIVE TEST USING GTS (CONTROL THE SHIFT POSITION) Click here

    A

  2. INSPECT SOLENOID (SL3) VALVE


    1. B007XRMC14
      *1 Solenoid (SL3) Valve

      Remove the solenoid (SL3) valve.

      Click here

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      1 - 2 20°C (68°F) 5.0 to 5.6 Ω

    3. Connect a positive (+) lead with a 21 W bulb from the battery to terminal 1 and a negative (-) lead 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.
      Result
      Proceed to
      OK
      NG

    NG

    REPLACE SOLENOID (SL3) VALVE Click here

    OK

  3. INSPECT TRANSMISSION VALVE BODY ASSEMBLY


    1. Inspect 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 TRANSAXLE ASSEMBLY Click here

    NG

    REPAIR OR REPLACE TRANSMISSION VALVE BODY ASSEMBLY Click here

  4. PERFORM ACTIVE TEST USING GTS (CONTROL THE SHIFT POSITION)

    Note

    This test should always be performed with at least 2 people.


    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 / Transmission / Active Test / Control the Shift Position.

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

      Tech Tips

      Comparing the gear commanded by the Active Test with the actual gear enables confirmation of the problem.

      Click here


      Powertrain > Transmission > Active Test
      Tester Display Measurement Item Control Range Diagnostic Note
      Control the Shift Position Operates the solenoid valves to allow gears to be selected manually

      1st/2nd/3rd/4th/5th/6th

      Start/Stop

      Can be used to check the operation of the solenoid valves.

      Upshifts and downshifts should be performed consecutively. A 10-second interval is required between gear changes.

      Do not downshift at high speeds. Doing so will damage the automatic transaxle.


        [Vehicle Condition]

      • 50 km/h (31 mph) or less

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

      Note


      • This Active Test can be performed when the vehicle is stopped.

      • When shifting gears using the Active Test, do not operate the accelerator pedal for 2 seconds before and after shifting gears.

      Tech Tips

      The gear commanded by the ECM is shown in the Data List / Shift Status display on the GTS.

    8. Check the vehicle speed and gear when the engine speed is 1000 rpm.

      Tech Tips

      As the torque converter clutch has not engaged, it may be difficult to obtain the speeds specified for 4th, 5th, and 6th gear, however a difference of speed should still be evident following each gear change.

      Standard
      1st 2nd 3rd 4th 5th 6th
      8 to 12 km/h (5 to 7 mph) 15 to 19 km/h (9 to 12 mph) 21 to 25 km/h (13 to 16 mph) 31 to 35 km/h (19 to 22 mph) 44 to 48 km/h (27 to 30 mph) 52 to 56 km/h (32 to 35 mph)

    9. Compare the ECM commanded gear and the actual gear.

      Result
      Actual Gear during Malfunction ECM Commanded Gear Proceed to
      1st 2nd 3rd 4th 5th 6th
      Solenoid (SL1) valve Stuck ON 1st 2nd 3rd 4th 4th 4th A
      Stuck OFF N*1 N*1 N*1 N*1 5th 6th
      Solenoid (SL2) valve Stuck ON 4th 4th 4th 4th 5th 6th B
      Stuck OFF 1st 2nd 3rd 1st N*1 N*1
      Solenoid (SL3) valve Stuck ON 2nd 2nd 3rd 4th 5th 6th C
      Stuck OFF 1st 1st 3rd 4th 5th N*1
      Solenoid (SL4) valve Stuck ON 3rd 3rd 3rd 4th 5th 5th D
      Stuck OFF 1st 2nd 1st 4th N*1 6th
      Solenoid (SLT) valve Stuck ON N*2 N*2 N*2 N*2 N*2 N*2 E
      Stuck OFF*3 1st 2nd 3rd 4th 5th 6th

      Tech Tips


      • *1: Neutral

      • *2: If the solenoid (SLT) valve is stuck ON, the line pressure will be low. Therefore, the amount of torque that can be transmitted by each gear will be lower than the normal limit. When the engine power exceeds this limit, the engine speed will increase freely.

      • *3: When the solenoid (SLT) valve is stuck OFF, gear shifting will be normal.


    A

    GO TO DTC CHART (DTC P07457F) Click here

    B

    GO TO DTC CHART (DTC P07757F) Click here

    C

    GO TO STEP 2 Click here

    D

    GO TO DTC CHART (DTC P28077F) Click here

    E

    GO TO DTC CHART (DTC P27137F) Click here