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Fail-Safe Chart

  1. Description 

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

  2. Fail-safe 
    1. Fail-safe control list
      FAIL-SAFE CONTROL LIST

      Malfunctioning Part Function
      Speed sensor NT
      • Prohibits shifting to 2nd and 8th
      • Lock up clutch control is prohibited
      • AI-SHIFT* control is prohibited
      • High response gear shifts are prohibited
      Speed sensor NC3
      • Lock up clutch control is prohibited
      • AI-SHIFT* control is prohibited
      • High response gear shifts are prohibited
      Speed sensor SP2
      • Prohibits shifting to 2nd and 8th
      • Lock up clutch control is prohibited
      • AI-SHIFT* control is prohibited
      • High response gear shifts are prohibited
      Shift solenoid valve SL1, 2, 3, 4, 5 and SR If the TCM detects a solenoid valve malfunction, it performs fail-safe control
      Transmission fluid temperature sensor
      • Shifting between 1st and 5th gear is allowed
      • Lock up clutch control is prohibited
      • AI-SHIFT* control is prohibited
      • High response gear shifts are prohibited
      Oil pressure switch Performs same control when there is a shift solenoid valve SL1 ON malfunction
      TCM power supply (voltage is low)
      • When driving in 1st to 7th, the transmission will be fixed in 7th
      • When driving in 8th, the transmission will be fixed in 8th
      Knock sensor
      • When driving in 1st to 5th, up-shift to 6th or above is prohibited
      • When driving in 6th or above, from the time the malfunction is detected, up-shift to higher gear is prohibited
      • Lock up clutch control is prohibited
      • High response gear shifts are prohibited
      CAN communication
      • Shifting to only either 1st or 3rd gear is allowed
      • Lock up clutch control is prohibited
      • High response gear shifts are prohibited
      Shift solenoid valve SLU and SL Lock up clutch control is prohibited
      Shift solenoid valve SLT
      • Engine output is limited
      • High response gear shifts are prohibited
      HINT
      *: In addition to the switching of the shift pattern through the pattern select switch, Artificial Intelligence Shift (AI-SHIFT) control enables the TCM to estimate the road conditions and driver intention in order to automatically select the optimal shift pattern.
    2. Shift Solenoid Valve Normal Operation Chart.
      SHIFT SOLENOID VALVE NORMAL OPERATION CHART

      Gear 1st 2nd 3rd 4th 5th 6th 7th 8th
      Shift Solenoid Valve SL1 ON ON ON ON ON OFF OFF OFF
      Shift Solenoid Valve SL2 OFF OFF OFF OFF ON ON ON ON
      Shift Solenoid Valve SL3 OFF OFF ON OFF OFF OFF ON OFF
      Shift Solenoid Valve SL4 OFF OFF OFF ON OFF ON OFF OFF
      Shift Solenoid Valve SL5 OFF ON OFF OFF OFF OFF OFF ON
    3. Fail-safe Control Chart
      Fig 1: Fail-Safe Control Chart
      G05750695Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

      HINT

      • *1: Operation of fail-safe is canceled the first time the vehicle stops.
      • *2. Operation of fail-safe is not canceled for subsequent vehicle stops. *3. Operation of fail-safe is canceled when a new trip is started.
      • *4. Operation of fail-safe is not canceled, as a vehicle stop was detected on the previous trip
      • *5: For the shift solenoid valve SL1 OFF malfunction, the 3rd trip is started with the failsafe ON
      • Fail-safe operation is performed when the TCM detects a malfunction.
      SHIFT SOLENOID VALVE OPERATION CHART

      Gear under normal conditions 1st 2nd 3rd 4th 5th 6th 7th 8th
      Shift Solenoid Valve SL1 ON malfunction (without fail-safe control) 1st 2nd 3rd 4th 5th 6th 7th 8th
      Fail-safe control during ON malfunction 1st 2nd 3rd 4th 5th 5th 5th 5th
      OFF malfunction (without fail-safe control) N N N N N 6th 7th 8th
      Fail-safe control during OFF malfunction 6th 6th 6th 6th 6th 6th 7th 8th
      Fail-safe control during OFF malfunction (from 3rd trip) Fixed in 3rd
      Shift Solenoid Valve SL2 ON malfunction (without fail-safe control) 5th 8th 7th 6th 5th 6th 7th 8th
      Fail-safe control during ON malfunction 5th 5th 5th 5th 5th 6th 7th 8th
      OFF malfunction (without fail-safe control) 1st 2nd 3rd 4th 1st N N N
      Fail-safe control during OFF malfunction (until vehicle stops) Fixed in 7th
      Fail-safe control during OFF malfunction*1 1st 2nd 3rd 4th 4th 4th 4th 4th
      Shift Solenoid Valve SL3 ON malfunction (without fail-safe control) 3rd 3rd 3rd 3rd 7th 7th 7th 7th
      Fail-safe control during ON malfunction (when malfunction is detected in 4th or below) Fixed in 3rd
      Fail-safe control during ON malfunction (when malfunction is detected in 5th or above) Fixed in 7th
      (If vehicle stops once, fixed in 3rd)
      OFF malfunction (without fail-safe control) 1st 2nd 1st 4th 5th 6th N 8th
      Fail-safe control during OFF malfunction (when malfunction is detected in 7th, gear is as shown in chart If down-shifted to 6th or below once, up-shift to 7th or above is prohibited) 1st 2nd 4th 4th 5th 6th 8th 8th
      Fail-safe control during OFF malfunction (when malfunction is detected in 6th or below) 1st 2nd 4th 4th 5th 6th 6th 6th
      Shift Solenoid Valve SL4 ON malfunction (without fail-safe control) 4th 4th 3rd 4th 6th 6th 7th 6th
      Fail-safe control during ON malfunction (when malfunction is detected in 4th or below) Fixed in 3rd
      Fail-safe control during ON malfunction (when malfunction is detected in 5th or above) Fixed in 7th
      (If vehicle stops once, fixed in 3rd)
      OFF malfunction (without fail-safe control) 1st 2nd 3rd 1st 5th N 7th 8th
      Fail-safe control during OFF malfunction (when malfunction is detected in 6th, gear is position as shown in chart If down-shifted to 5th or below once, upshift to 4th, 6th, 7th, and 8th is prohibited) 1st 2nd 3rd 5th 5th 7th 7th 7th
      Fail-safe control during OFF malfunction (when malfunction is detected in 4th) 1st 2nd 3rd 5th 5th 5th 5th 5th
      Shift Solenoid Valve SL5 ON malfunction (without fail-safe control) 2nd 2nd 3rd 4th 8th 6th 7th 8th
      Fail-safe control during ON malfunction (when malfunction is detected in 4th or below) Fixed in 3rd
      Fail-safe control during ON malfunction (when malfunction is detected in 5th or above) Fixed in 7th
      (If vehicle stops once, fixed in 3rd)
      OFF malfunction (without fail-safe control) 1st 1st 3rd 4th 5th 6th 7th N
      Fail-safe control during OFF malfunction 1st 3rd 3rd 4th 5th 6th 7th 7th
      Shift Solenoid Valve SR OFF malfunction (when malfunction occurs in 5th or below) 1st 2nd 3rd 4th 1st 7th 7th 7th
      OFF malfunction (when malfunction occurs in 6th or above, or after vehicle shifts to 7th) 7th 7th 7th 7th 7th 7th 7th 7th
      Fail-safe control during OFF malfunction (when malfunction is detected in 5th or above) Fixed in 7th
      OFF malfunction (trip is started in malfunctioning state) 3rd 3rd 3rd 3rd 7th 7th 7th 7th
      Fail-safe control during OFF malfunction (when malfunction is detected in 4th or below) Fixed in 3rd
      Fail-safe control during OFF malfunction (when malfunction is detected in 5th or above*2) Fixed in 7th
      (If vehicle stops once, fixed in 3rd)
      HINT
      • *1. When vehicle is driven after fail-safe detection.
      • *2. After trip is started in malfunctioning state
      • In case of an open or short circuit, the TCM stops sending current to the open or short circuited solenoid
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