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Fail-Safe Chart

  1. FAIL-SAFE FUNCTION 
    1. When communication fails in any of the CAN bus wires (communication wires) due to a short circuit or other causes, the fail-safe function which is specified for each system, operates to prevent the system from malfunctioning.
    2. The following chart shows the relationships between components, system functions, and effects of communication failure on these functions. (For further details, see the pages for each system.)
      FAIL-SAFE CHART

      Function (Function Description) Control Master System Related Fail-safe Operation DTC (Driver Detectable)
      VSC control*1 (Controls driving force while VSC in operation) Skid Control ECU
      • ECM
      • Steering Angle Sensor
      • Yaw Rate Sensor
      		 VSC control is inoperative (VSC control gradually stops) U0073, U0100, U0123, U0124, U0126 (Warning light comes on)
      VSC control*1 (Engine power control by VSC/TRC) Skid Control ECU
      • ECM
      • Steering Angle Sensor
      • Yaw Rate Sensor
      		 VSC control is inoperative (VSC control gradually stops) U0073, U0100, U0123, U0124, U0126 (Warning light comes on)
      ABS control (Controls driving force while ABS in operation) Skid Control ECU Yaw Rate Sensor*1 Control inoperative (gradually stops controlling during ABS control) U0073, U0123, U0124*1 (Warning light comes on)
      Electric power steering (Speed of vehicle induction type torque control) Power Steering ECU
      • ECM
      • Skid Control ECU
      • Steering Angle Sensor
      • Combination Meter
      		 Depression of EPS assist (Deterioration of steering) U0100, U0129 (VSC failure: warning light comes on, and decrease of assistance power at vehicle speed 70 km/h) (ECM failure: Warning light comes on [only before assist beginning])
      Meter display (Displays operation condition and DTCs) Combination Meter
      • ECM
      • Skid Control ECU
      • Center Airbag Sensor Assembly
      • Main Body ECU
      • Air Conditioning amplifier
      • 4WD Control ECU
      • Power Steering ECU
      		 Light does not come on, illuminates abnormally, or blinks abnormally Abnormal light illumination
      Air conditioning control Air Conditioning Amplifier
      • ECM
      • Combination Meter
      • Main Body ECU
      		 Air conditioning function and PTC heater function stop B1499 (Air Conditioning inoperative)
      CAN No. 2 bus monitoring function Network Gateway ECU 4WD Control ECU Communication error is detected U0114, U1002 (Not detectable)
      4WD control*2 (Distribution of the driving force in the rear and front wheel is controlled by running state of the vehicle) 4WD Control ECU
      • ECM
      • Skid Control ECU
      • Steering Angle Sensor
      		 4WD function stops (the same as 2WD) U0073, U0100, U0126, U0129 (Warning light comes on)
      HINT:
      *1: w/VSC
      *2: for 4WD
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