Fail-Safe Chart
- FAIL-SAFE FUNCTION
- 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.
- The following chart shows the relationships between components, system functions, and effects of communication failure on these functions.
Function
(Function Description)Control Master System Related Fail-safe Operation DTC
(Driver Detectable)VSC control
(Controls driving force while VSC is operating)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
(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 is operating)Skid Control ECU Yaw Rate Sensor Control inoperative
(gradually stops controlling during ABS control)U0073, U0123, U0124
(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 starts])Meter display (Displays operation condition and DTCs) Combination Meter - ECM
- Skid Control ECU
- Center Airbag Sensor Assembly
- Main Body ECU
- 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
- Accessory gateway
Air conditioning function and PTC heater function stop B1499
(Air Conditioning inoperative)Event data recorder Center Airbag Sensor - ECM
- Combination Meter
Records invalid values in the event data recorder. None
(Impossible)Buzzer control (sounds the buzzer in the combination meter according to a buzzer sounding request from each ECU) Combination Meter - ECM
- Skid Control ECU
- Power Steering ECU
- Main Body ECU
Buzzer function stops None
(Abnormal light illumination)4WD control*1
(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: for 4WD