Can Communication System Fail-Safe Chart

Power Source Network. Corolla. Zre142 Aze141
Networking. Corolla. Zre142 Aze141

  1. FAIL-SAFE FUNCTION

Can Communication System -- Fail-Safe Chart



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.)

    Function
    (Function Description)
    		Control Master
    		System Related
    		Fail-safe Operation
    		DTC
    (Driver Detectable)
    Neutral control
    		ECM
    		Skid control ECU
    		Neutral control stops
    		U0129*3
    (Impossible)
    Air conditioning control
    		Air Conditioning Amplifier
    1. ECM
    2. Combination Meter
    3. Main Body ECU
    4. Accessory Gateway
    		Air conditioning function and PTC heater function stop
    		B1499
    (Air Conditioning inoperative)
    VSC control*1
    (Controls driving force while VSC in operation)
    		Skid Control ECU
    1. ECM
    2. Steering Angle Sensor
    3. 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
    1. ECM
    2. Steering Angle Sensor
    3. Yaw Rate Sensor
    		VSC control is inoperative
    (VSC control gradually stops)
    		U0073, U0100, U0123, U0124, U0126
    (Warning light comes on)
    ABS control*1
    (Controls driving force while ABS in operation)
    		Skid Control ECU
    		Yaw Rate Sensor
    		Control inoperative
    (gradually stops controlling during ABS control)
    		U0073, U0123, U0124
    (Warning light comes on)
    ABS control*2
    (Controls driving force while ABS in operation)
    		Skid Control ECU
    		ECM
    		Control inoperative
    (gradually stops controlling during ABS control)
    		U0073
    (Warning light comes on)
    Electric power steering
    (Speed of vehicle induction type torque control)
    		Power Steering ECU
    1. ECM
    2. Skid Control ECU
    3. Steering Angle Sensor
    4. Combination Meter
    5. Accessory Gateway
    		VSC Malfunction: 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 begins])
    ECM Malfunction (before assist begins): stop the assist operation
    ECM Malfunction (after assist begins): continue the assist operation
    Entry function/Power door lock control*3
    		Main Body ECU
    1. ECM
    2. Accessory Gateway
    3. Center Airbag Sensor Assembly
    4. Combination Meter
    5. Certification ECU
    		The door lock cannot be released for smart entry
    		U0327, U1002
    (Wireless door lock cannot operate)
    Immobiliser control*3
    (Alarm control and remote engine start control)
    		Certification ECU
    1. ECM
    2. Accessory Gateway
    3. Air Conditioning Amplifier
    4. Combination Meter
    5. Main Body ECU
    		The engine starting is not possible by smart entry
    		U0327, U1002
    (Possible)
    Meter display (Displays operation condition and DTCs)
    		Combination Meter
    1. ECM
    2. Skid Control ECU
    3. Power Steering ECU
    4. Center Airbag Sensor Assembly
    5. Certification ECU
    6. Main Body ECU
    		Light does not come on, illuminates abnormally, or blinks abnormally
    		U0100, U0129
    (Abnormal light illumination)
    Buzzer control (sounds the buzzer in the combination meter according to a buzzer sounding request from each ECU)
    		Combination Meter
    1. ECM
    2. Skid Control ECU
    3. Power Steering ECU
    4. Main Body ECU
    5. Certification ECU
    		Buzzer function stops
    		None
    (Abnormal light illumination)
    *1: w/ VSC
    *2: w/o VSC
    *3: w/ Smart key system