AUTOMATIC TRANSAXLE SYSTEM, Diagnostic DTC:P0746

DTC Code DTC Name
P0746 Pressure Control Solenoid "A" Performance or Stuck OFF

SYSTEM DESCRIPTION

The ECM uses the vehicle speed signal and signals from the transmission speed sensors (NC and NT) 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
P0746 Pressure Control Solenoid "A" Performance or Stuck OFF

All of the following conditions are met (2-trip detection logic):


  • The engine coolant temperature is 40°C (104°F) or higher.

  • The ATF temperature is -10°C (14°F) or higher.

  • 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 sensors (NT and NC), coolant temperature sensor, oil temperature sensor, knock sensor, electronic throttle or CAN communication system.

  • Any of the following conditions are met:


    • When the ECM commands the transaxle to shift to 1st, 2nd, 3rd or 4th gear, the engine overruns (neutral status).

    • When the ECM commands the transaxle to shift to 5th or 6th gear, the actual gear changes to 4th.

  • Solenoid (SL1) valve remains open or closed

  • Transmission valve body assembly is blocked

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

 Comes on DTC stored
DTC Detection Condition Patterns:
Vehicle Condition
Pattern 1 Pattern 2 Pattern 3 Pattern 4 Pattern 5 Pattern 6
Diagnostic Condition The engine coolant temperature is 40°C (104°F) or higher. ○ ○ ○ ○ ○ ○
The ATF temperature is -10°C (14°F) or higher. ○ ○ ○ ○ ○ ○
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 sensors (NT and NC), coolant temperature sensor, oil temperature sensor, knock sensor, electronic throttle or CAN communication system. ○ ○ ○ ○ ○ ○
Malfunction Condition When the ECM commands the transaxle to shift to 1st gear, the engine overruns (neutral status). ○ - - - - -
When the ECM commands the transaxle to shift to 2nd gear, the engine overruns (neutral status). - ○ - - - -
When the ECM commands the transaxle to shift to 3rd gear, the engine overruns (neutral status). - - ○ - - -
When the ECM commands the transaxle to shift to 4th gear, the engine overruns (neutral status). - - - ○ - -
When the ECM commands the transaxle to shift to 5th gear, the actual gear changes to 4th. - - - - ○ -
When the ECM commands the transaxle to shift to 6th gear, the actual gear changes to 4th. - - - - - ○
Duration 0.5 seconds or more 0.5 seconds or more 0.5 seconds or more 0.5 seconds or more 0.8 seconds or more 0.8 seconds or more
Detection Logic 2-trip detection logic 2-trip detection logic 2-trip detection logic 2-trip detection logic 2-trip detection logic 2-trip detection logic

Tech Tips

This DTC is stored when any of the above detection patterns are met.

MONITOR DESCRIPTION

The ECM commands gear shifts by turning the solenoid valves on and off. According to the input shaft revolution (speed) and intermediate (counter) 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.

CONFIRMATION DRIVING PATTERN

CAUTION:

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

Tech Tips

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.


  1. Connect the GTS to the DLC3.

  2. Turn the ignition switch to ON and turn the GTS on.

  3. Clear the DTCs (even if no DTCs are stored, perform the clear DTC procedure).

  4. Turn the ignition switch off and wait for 2 minutes or more.

  5. Turn the ignition switch to ON and turn the GTS on.

  6. Start the engine.

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

    Click here

  8. Stop the vehicle.

  9. Enter the following menus: Powertrain / Engine and ECT / Utility / All Readiness.

  10. Input the DTC: P0746.

  11. Check the DTC judgment result.

    GTS 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

    Tech Tips


    • 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 Confirmation Driving Pattern and check the DTC judgment result again.

CAUTION / NOTICE / HINT

CAUTION:


  • B0070MF

    Strictly obey all traffic rules and regulations.

  • Do not drive the vehicle with the GTS cable contacting the pedals, shift lever or steering wheel.

  • Driving the wheel with the GTS cable contacting these areas could impede vehicle control, resulting in a serious accident.


  • B0070WA

    Do not operate the GTS while driving the vehicle.

  • Operating the GTS while driving the vehicle will prevent you from paying sufficient attention to vehicle surroundings, and could result in a serious accident.

Note

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

Click here

PROCEDURE


  1. CHECK OTHER DTCS OUTPUT (IN ADDITION TO DTC P0746)


    1. Connect the GTS to the DLC3.

    2. Turn the ignition switch to ON.

    3. Turn the GTS on.

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


      Powertrain > Engine and ECT > Trouble Codes

    5. Read the DTCs using the GTS.

      Result
      Result Proceed to
      Only DTC P0746 is output A
      DTC P0746 and other DTCs are output B

      Tech Tips

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


    A

    GO TO STEP 3 Click here

    B

  2. 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 ignition switch off.

    3. Connect the GTS to the DLC3.

    4. Turn the ignition switch to ON.

    5. Turn the GTS on.

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

    7. Perform the Active Test according to the display on the GTS.

      Tech Tips

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

      Click here


      Powertrain > Engine and ECT > 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

      • Press "→" button: Upshift occurs

      • Press "←" button: Downshift occurs

      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 > Engine and ECT > 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 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.


    B

    GO TO DTC CHART (DTC P0776) Click here

    C

    GO TO DTC CHART (DTC P0796) Click here

    D

    GO TO DTC CHART (DTC P2808) Click here

    E

    GO TO DTC CHART (DTC P2714) Click here

    A

  3. INSPECT SOLENOID (SL1) VALVE


    1. B00713YC02
      *1 Solenoid (SL1) Valve

      Remove the solenoid (SL1) 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 from the battery with a 21 W bulb to terminal 2 and a negative (-) lead to terminal 1 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 (SL1) VALVE Click here

    OK

  4. 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 TRANSAXLE ASSEMBLY Click here

    NG

    REPAIR OR REPLACE TRANSMISSION VALVE BODY ASSEMBLY Click here