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Home >> Scion >> 2009 >> xB Automatic >> Repair and Diagnosis >> Transmission >> U241E Automatic Transaxle >> Automatic Transaxle System >> Fail-Safe Chart

Fail-Safe Chart

  1. FAIL-SAFE CHART 

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

    1. Automatic Transmission Fluid (ATF) temperature sensor:

      When the ATF temperature sensor has a malfunction, 4 up-shift is prohibited.

    2. Counter gear speed sensor NC (Speed sensor NC): When the counter gear speed sensor has a malfunction, 4 up-shift is prohibited.
    3. Shift solenoid valve DSL:

      When the solenoid valve DSL has a malfunction, the current to the solenoid valve is stopped. This stops lock-up control, then fuel economy decreases.

    4. Shift solenoid valve SL1, SL2 and S4:

      If any of the shift solenoid valve circuits develops an open or short, the ECM turns the other shift solenoid "ON" and "OFF" in order to shift into the gear positions shown in the table below. Manual shifting as shown in the following table must be done. In case of a short circuit, the ECM stops sending the current to the short circuited solenoid. Even if starting the engine in the fail-safe mode, the gear position remains in the same position.

      SHIFT SOLENOID VALVE SL1 AND SL2 SPECIFICATIONS

      Normal Shift Solenoid Valve SL1 Shift Solenoid Valve SL2 Shift Solenoid Valve S4
      Gear Solenoid Valve Gear Solenoid Valve Gear Solenoid Valve Gear Solenoid Valve
      SL1 SL2 S4 SL1 SL2 S4 SL1 SL2 S4 SL1 SL2 S4
      1st ON ON OFF 2nd X ON OFF 3rd ON
      ↓
      OFF      		 X OFF 1st ON ON X
      2nd OFF ON OFF 2nd X ON OFF 3rd OFF X OFF 2nd OFF ON X
      3rd OFF OFF OFF 3rd X OFF
      ↓
      ON      		 OFF
      ↓
      ON      		 3rd OFF X OFF 3rd OFF OFF X
      4th OFF OFF ON 3rd X OFF
      ↓
      ON      		 ON 4th OFF X ON 3rd OFF OFF X
      HINT:
      • ↓: Condition in the normal operation is shown above the "↓".
      • ↓: Condition in the fail-safe mode is shown beneath the "↓".
      • E/B: Engine brake.
      SHIFT SOLENOID VALVE SL1 & S4 AND SL2 & S4 SPECIFICATIONS

      Shift Solenoid Valve SL1 and SL2 Shift Solenoid Valve SL1 and S4 Shift Solenoid Valve SL2 and S4 Shift Solenoid Valve SL1, SL2 and S4
      Gear Solenoid Valve Gear Solenoid Valve Gear Solenoid Valve Gear Solenoid Valve
      SL1 SL2 S4 SL1 SL2 S4 SL1 SL2 S4 SL1 SL2 S4
      3rd X X OFF 2nd X ON X 3rd ON
      ↓
      OFF      		 X X 3rd X X X
      3rd X X OFF 2nd X ON X 3rd OFF X X 3rd X X X
      3rd X X OFF 2nd X OFF
      ↓
      ON      		 X 3rd OFF X X 3rd X X X
      4th X X ON 2nd X OFF
      ↓
      ON      		 X 3rd OFF X X 3rd X X X
      HINT:
      • ↓: Condition in the normal operation is shown above the "↓".
      • ↓: Condition in the fail-safe mode is shown beneath the "↓".
      • E/B: Engine brake.
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