AUTOMATIC TRANSMISSION SYSTEM FAIL-SAFE CHART


  1. FAIL-SAFE CHART

    This function minimizes the loss of the ECT functions when any malfunction occurs in each sensor or solenoid.

    Malfunction Part Function

    DTC P0717:

    Input Speed Sensor NT

    During an input speed sensor malfunction, shift control is effected through the output speed sensor signal SP2.

    During an input speed sensor malfunction, up-shift to the 5th and 6th, AI-SHIFT*1and flex lock-up clutch control are prohibited.

    DTC P0722:

    Output Speed Sensor SP2

    During an output speed sensor malfunction, shift control is effected through the input speed sensor signal NT.

    During an output speed sensor malfunction, up-shift to the 5th and 6th, AI-SHIFT*1and flex lock-up clutch control are prohibited.

    DTC P0711, P0712, P0713:

    ATF Temperature Sensor

    		 During an ATF temperature sensor malfunction, up-shift to the 5th and 6th and flex lock-up clutch control are prohibited.
    Shift Solenoid Valve S1, S2, S3, S4 and SR If the solenoid valve system is open or shorted, the TCM cuts power to all solenoids, leaving just the mechanical hydraulic circuit, requiring manual shifting (fixed to 4th).

    DTC P0776, P0961, P0962, P0963, P0965, P0966, P0967:

    Shift Solenoid Valve SL1 and SL2

    		 During a solenoid valve SL1 or SL2 malfunction, up-shift to the 5th and 6th and flex lock-up clutch control are prohibited.

    DTC P2757, P2758, P2762, P2763, P2764:

    Shift Solenoid Valve SLU

    		 During a solenoid valve SLU malfunction, the current to the solenoid valve is stopped. This stops lock-up control and flex lock-up control, fuel economy decreases.

    DTC P2714, P2719, P2720, P2721:

    Shift Solenoid Valve SLT

    		 During a solenoid valve SLT malfunction, the current to the solenoid valve is stopped. This stops line pressure optimal control, the shift shock increases. However, shifting is effected through normal clutch pressure control.

    *: AI (Artificial Intelligence) -SHIFT control

    In addition to the switching of the shift pattern through the pattern select switch, the AI-SHIFT control enables the ECM to estimate the road conditions and the driver's intention in order to automatically select the optimal shift pattern. As a result, a comfortable ride has been realized.


    1. Fail-safe operation for electronically malfunctioning shift solenoid valve (S1, S2, S3, S4 and SR):

      Tech Tips

      Fail-safe operation in the event of an electric system malfunction.

      Fail safe function:

      If either of the shift solenoid valve circuits has an open or short failure, the ECM turns the other shift solenoid "ON" and "OFF" in order to shift into the gear positions shown in the table below.

      In case of a short circuit, the ECM stops sending current to the short circuited solenoid.

      Even if staring the engine again in the fail-safe mode, the gear position remains in the same position.

      Operating Condition of Shift Solenoid Valves
      Shift Lever Position or Shift Range Gear Position Shift Solenoid Valve
      S1 S2 S3 S4 SR SL1 SL2 SLU
      P Park Off On On On On Off On Off
      R* Reverse Off On On On On On On Off
      N Neutral Off On On On On On On Off
      D, M6 1st Off On On Off On Off On Off
      2nd On On On On On Off Off On
      3rd On Off On Off On Off Off On
      4th* On Off Off Off On Off On On
      5th* On Off Off On Off On Off On
      6th* On On Off On Off On Off On
      M5 1st Off On On Off On Off On Off
      2nd On On On On On Off Off On
      3rd On Off On Off On Off Off On
      4th* On Off Off Off On Off On On
      5th* On Off Off On Off On Off On
      M4 1st Off On On Off On Off On Off
      2nd On On On On On Off Off On
      3rd On Off On Off On Off Off On
      4th* On Off Off Off On Off On On
      M3 1st Off On On Off On Off On Off
      2nd On On On On On Off Off Off
      3rd* On Off On Off On Off Off Off
      M2 1st Off On On Off On Off On On
      2nd* On On On On On Off Off Off
      M1 1st* Off On On Off On Off Off Off

      Tech Tips

      *: Engine braking occurs

    2. Fail-safe operation for mechanically malfunction:

      Tech Tips

      Fail-safe operation in the event of a mechanical system malfunction.

      Fail safe function:

      The ECM controls the gear position as shown in the table below when malfunctions occur.

      Fail-safe chart for mechanical malfunction:
      DTC Condition

      Gear*1

      - Normal 1st 2nd 3rd 4th 5th 6th
      P0751

      Shift solenoid valve S1:

      Stuck OFF malfunction

      1st*2

      		2nd ↑ 3rd 3rd 3rd
      P0762

      Shift solenoid S3:

      Stuck ON malfunction

      		 1st 2nd ↑ 3rd 3rd 3rd
      P0766

      Shift solenoid valve S4, Shift solenoid valve SL2 or Valve body (Brake control valve):

      Malfunction

      		 1st 2nd ↑ 3rd 3rd 3rd
      P0781

      Valve body (1-2 shift valve):

      Malfunction

      1st*2

      		2nd ↑ 3rd 3rd 3rd
      P0729

      Valve body (Sequence valve):

      Malfunction

      		 1st 2nd ↑ 4th 5th 5th

      Tech Tips


      • *1: Actual gear shift (gear position) under fail-safe operation

      • *2: Under engine braking, downshifting to 1st or 2nd gear is prohibited.