CAN COMMUNICATION SYSTEM(w/o Central Gateway ECU) FAIL-SAFE CHART


  1. FAIL-SAFE FUNCTION


    1. When communication fails in any of the CAN bus lines (communication lines), a fail-safe function(s) will operate. The fail-safe function that is specified for each system operates to prevent those systems from malfunctioning.

    2. The following table shows the effects on each system when communication is impossible. (For further details, see the pages for each system.)

      Function Control Master System Related Fail-safe Operation Driver Detectable

      DTC Detection

      (ECU that stored DTC)

      Anti-lock Brake System Control


      • Prevents the wheels from locking during sudden stops.

      		 Brake actuator assembly -

      • During control: When back-up control (stabilizing the vehicle) is complete, the system changes to normal braking and prohibits control.

      • Not during control: Control cannot be performed.

      • Brake warning light illuminates.

      • ABS warning light illuminates.

      U0073

      (Brake actuator assembly)

      Vehicle Stability Control / Traction Control


      • Suppresses vehicle instability, such as sliding sideways when cornering and wheel slippage when accelerating from rest.

      		 Brake actuator assembly

      • ECM

      • Airbag sensor assembly

      • Steering sensor (Spiral cable with sensor sub-assembly)

      • Power steering ECU assembly

      • During control: When back-up control (stabilizing the vehicle) is complete, the system changes to normal braking and prohibits control.

      • Not during control: Control cannot be performed.

      • Brake warning light illuminates.

      • ABS warning light illuminates.

      • SLIP warning light illuminates.

      U0073

      U0100

      U0123

      U0126

      (Brake actuator assembly)

      Hill-start Assist Contol


      • Maintains brake pressure for 2 seconds when the brake pedal has been depressed further after stopping the vehicle.

      		 Brake actuator assembly

      • ECM

      • Airbag sensor assembly

      • Steering sensor (Spiral cable with sensor sub-assembly)

      • During control: When back-up control (depressurization control) is complete, further control cannot be performed.

      • Not during control: Control cannot be performed.

      • Brake warning light illuminates.

      • ABS warning light illuminates.

      • SLIP warning light illuminates.

      U0073

      U0100

      U0123

      U0126

      (Brake actuator assembly)

      Eco Drive Hill Hold Control


      • Maintains brake fluid pressure when changing foot position from the brake pedal to accelerator pedal and starting the engine during eco drive hill hold control. Fluid pressure is held for a maximum of 2 seconds, and then released in 1 second.

      		 Brake actuator assembly

      • ECM

      • Airbag sensor assembly

      • Steering sensor (Spiral cable with sensor sub-assembly)

      • Engine stop and start ECU

      • During control: When back-up control (depressurization control) is complete, further control cannot be performed.

      • Not during control: Control cannot be performed.

      • Brake warning light illuminates.

      • ABS warning light illuminates.

      • SLIP warning light illuminates.

      U0073

      U0100

      U0123

      U0124

      U0126

      (Brake actuator assembly)

      Air Conditioning Control


      • Corrects engine speed, such as for idle up.

      • Controls outlet air temperature, outlet mode change and airflow volume based on engine coolant temperature signal.

      • Corrects engine coolant temperature map and changes compressor lock judgment value.

      		 Air conditioning amplifier assembly ECM

      • Control is performed based on default coolant temperature of 80°C (176°F).

      • Control is performed based on engine model (differs between vehicle models).

      		 -

      U0100

      (Air conditioning amplifier assembly)

      Compressor Control


      • Determines whether the compressor is locked using engine speed information.

      		 Air conditioning amplifier assembly ECM Control is performed based on default engine speed of 0 rpm. -

      U0100

      (Air conditioning amplifier assembly)

      Simple Load Control


      • Limits electrical load control according to the load control level.

      		 Air conditioning amplifier assembly Power steering ECU assembly Maintains the latest state (load control is not performed when the system is reset). -

      U0131

      (Air conditioning amplifier assembly)

      Panel Dimming Control


      • Controls air conditioning system operation state display and air conditioning control panel switch indicator output based on air conditioning control panel switch operation.

      • If automatic circulation control is available, changes the air inlet mode to fresh air or recirculate mode based on information from the smog ventilation sensor.

      		 Air conditioning amplifier assembly Radio and display receiver assembly Control is performed based on default A/C switch state of off and emission existence information is maintained. -

      U0163

      (Air conditioning amplifier assembly)

      Destination Identification Control


      • Changes air conditioning control pattern according to destination.

      		 Air conditioning amplifier assembly Main body ECU (Multiplex network body ECU) Maintains the latest state. -

      U0142

      (Air conditioning amplifier assembly)

      Ambient Temperature Correction Control


      • Switches air conditioning system operation condition and corrects value of displayed ambient temperature according to vehicle speed signal.

      		 Air conditioning amplifier assembly Combination meter assembly Control is performed based on default vehicle speed of 0 km/h (0 mph).

      • Correction level for displayed ambient temperature declines.

      • Correction level for outlet airflow declines.

      U0155

      (Air conditioning amplifier assembly)

      Air Conditioning Eco Mode Control


      • Performs control in Eco mode using B_ECOMI

      		 Air conditioning amplifier assembly ECM Maintains the latest state (Maintained in normal condition after reset) -

      U0101

      (Air conditioning amplifier assembly)

      Leveling Control


      • Adjusts headlights vertical aiming according to wheel speed and vehicle pitch angle determined using vehicle height sensor.

      		 AFS ECU (Headlight swivel ECU assembly)

      • ECM

      • Brake actuator assembly

      • Main body ECU (Multiplex network body ECU)

      • Control is performed based on default vehicle speed of 0 km/h (0 mph).

      • Headlight swivel stops with the headlights facing forward.

      • AFS OFF indicator light flashes.

      • When an error occurs in the vehicle speed sensor waveform cycle during acceleration, the system will judge that the vehicle is being driven at a constant speed because the detected vehicle speed does not change. As a result, leveling control does not follow the changes in pitch angle. In this case, the headlights may dazzle oncoming vehicles.

      • When an error occurs in the vehicle speed sensor waveform cycle during deceleration, the system will judge that the vehicle is being driven at a constant speed because the detected vehicle speed does not change. As a result, leveling control does not follow the changes in pitch angle. In this case, visible distance shortens.

      • When an error occurs in the vehicle speed sensor waveform cycle during acceleration or deceleration, the headlights will not swivel smoothly because the detected vehicle speed changes suddenly.

      U0073

      U0100

      U0129

      U0142

      (AFS ECU (Headlight swivel ECU assembly))

      Swivel Control


      • Swings headlights left or right according to wheel speed and steering angle.

      		 AFS ECU (Headlight swivel ECU assembly)

      • ECM

      • Brake actuator assembly

      • Steering sensor (Spiral cable with sensor sub-assembly)

      • Main body ECU (Multiplex network body ECU)

      • Control is performed based on default vehicle speed of 0 km/h (0 mph).

      • Headlight swivel stops with the headlights facing forward.

      • AFS OFF indicator light flashes.

      • Headlights return to the front and then start swiveling when the correct position signal is received.

      • When an error occurs in the vehicle speed sensor waveform cycle during acceleration, the system will judge that the vehicle is being driven at a constant speed because the detected vehicle speed does not change. As a result, leveling control does not follow the changes in pitch angle. In this case, the headlights may dazzle oncoming vehicles.

      • When an error occurs in the vehicle speed sensor waveform cycle during deceleration, the system will judge that the vehicle is being driven at a constant speed because the detected vehicle speed does not change. As a result, leveling control does not follow the changes in pitch angle. In this case, visible distance shortens.

      • When an error occurs in the vehicle speed sensor waveform cycle during acceleration or deceleration, the headlights will not swivel smoothly because the detected vehicle speed changes suddenly.

      • When an error occurs in the vehicle speed sensor waveform cycle during turning, the headlights will not swivel smoothly because the detected steering angle changes suddenly.

      U0073

      U0100

      U0101

      U0126

      U0129

      U0142

      (AFS ECU (Headlight swivel ECU assembly))

      AFS OFF Indicator Light


      • Monitors for AFS (Adaptive Front-lighting System) malfunctions and blinks the indicator light in the combination meter assembly when a malfunction is detected.

      		 AFS ECU (Headlight swivel ECU assembly) Combination meter assembly Maintains the same condition. -

      U0073

      (AFS ECU (Headlight swivel ECU assembly))

      Destination Identification


      • Identifies destination based on destination and destination package information, and selects the time zone and language used for the display.

      		 Radio and display receiver assembly Main body ECU (Multiplex network body ECU) Destination is identified based on the latest value (based on the default value if data has never been received) and operation continues. Time zone and language selection screen are different from actual destination.

      U0140

      (Radio and display receiver assembly)

      Door Lock


      • Controls key linked and automatic door lock/unlock function, key confinement prevention function, etc.

      		 Main body ECU (Multiplex network body ECU)

      • Combination meter assembly

      • ECM

      • Brake actuator assembly

      • When the ignition switch is ON, control is performed based on the latest information.

      • When the ignition switch is off, key linked operation is permitted.

      • Speed sensitive automatic lock control does not occur.

      • Shift linked automatic lock control does not occur.

      • Shift linked automatic unlock control does not occur.

      • Automatic lock/unlock cannot be changed.

      		 -

      U0100

      U0101

      U0151

      U0155

      (Main body ECU (Multiplex network body ECU))

      Display Automatic Dimming


      • Display dimming control.

      		 Main body ECU (Multiplex network body ECU) Combination meter assembly Automatic dimming control for displays does not operate when taillights are turned on. -

      U0155

      (Main body ECU (Multiplex network body ECU))

      Illumination


      • Performs illumination control.

      		 Main body ECU (Multiplex network body ECU)

      • Certification ECU (Smart key ECU assembly)

      • ECM

      		 The dome light is turned off. The dome light does not turn off immediately after the doors are opened and closed.

      U0100

      U0327

      (Main body ECU (Multiplex network body ECU))
      Entry Function/Wireless Control Certification ECU (Smart key ECU assembly) Main body ECU (Multiplex network body ECU) Entry lock/unlock control is not possible. -

      U0327

      (Main body ECU (Multiplex network body ECU))

      Light Control


      • Daytime running light control.

      		 Main body ECU (Multiplex network body ECU)

      • ECM

      • Brake actuator assembly

      		 The daytime running light control does not operate. -

      U0100

      (Main body ECU (Multiplex network body ECU))

      Back Door Opener


      • Back door open control.

      		 Main body ECU (Multiplex network body ECU) Combination meter assembly The back door open control does not operate. -

      U0155

      (Main body ECU (Multiplex network body ECU))
      Display Dimming Control Clearance warning ECU assembly Main body ECU (Multiplex network body ECU)

      • When communication is interrupted when the ignition switch is turned to ON, control is performed based on default value (dimming).

      • When communication is interrupted while the ignition switch is ON, control is performed based on the latest information.

      		 -

      U0142

      (Clearance warning ECU assembly)

      Shift Position Judgment


      • Receives a shift position signal and uses it as a clearance sonar detection operation condition (for AT vehicles).

      		 Clearance warning ECU assembly ECM Operation continues at the default shift position of P. -

      U0101

      (Clearance warning ECU assembly)

      Vehicle Speed Judgment


      • Receives a vehicle speed signal and uses it as a clearance sonar detection operation condition.

      		 Clearance warning ECU assembly Combination meter assembly Operation continues at the default vehicle speed of 20 km/h (12 mph) or more. -

      U0129

      (Clearance warning ECU assembly)

      Distance Correction


      • Corrects distance measured using the ultra sonic sensors based on outside temperature signal.

      		 Clearance warning ECU assembly Air conditioning amplifier assembly

      • Operation continues at the default outside temperature of 25°C (77°F).

      • Simple intelligent parking assist system operation is canceled.

      		 Simple intelligent parking assist system operation is canceled (indicator is displayed on the combination meter assembly and the buzzer sounds).

      U0164

      (Clearance warning ECU assembly)

      Parking Brake Judgment


      • Receives a parking brake signal and uses it as a clearance sonar detection operation condition.

        (for MT vehicles)

      		 Clearance warning ECU assembly Main body ECU (Multiplex network body ECU) When communication is interrupted, the system judges the parking brake is ON. -

      U0142

      (Clearance warning ECU assembly)

      Engine Status Check


      • Checks engine status and uses it to judge if the simple intelligent parking assist system can be used.

      		 Clearance warning ECU assembly

      • Engine stop and start ECU

      • ECM

      (w/ Stop and start system)


      • When communication is interrupted when the ignition switch is turned to ON, the simple intelligent parking assist system cannot be operated.

      • When communication is interrupted while the ignition switch is ON, operation is performed based on the latest value.

      		 When the latest value is zero or communication is interrupted just after the ignition switch is turned to ON, simple intelligent parking assist system operation is canceled (indicator is displayed on the combination meter assembly and the buzzer sounds). -
      ECM

      (w/o Stop and start system)

      When communication is interrupted, simple intelligent parking assist system operation is canceled.

      		 Simple intelligent parking assist system operation is canceled (indicator is displayed on the combination meter assembly and the buzzer sounds).

      U0100

      (Clearance warning ECU assembly)

      Brake Status Judgment


      • Checks brake status and uses it to judge if the simple intelligent parking assist system can be used.

      		 Clearance warning ECU assembly Brake actuator assembly When communication is interrupted, simple intelligent parking assist system operation is canceled. -

      U0129

      (Clearance warning ECU assembly)

      Vehicle Information Judgment


      • Judges whether the vehicle is AT or MT, RHD or LHD and equipped with the stop and start system, and changes control.

      		 Clearance warning ECU assembly

      • ECM

      • Main body ECU (Multiplex network body ECU)

      • When AT/MT cannot be judged, operation is performed based on the latest value. When communication is interrupted when the ignition switch is turned to ON, the simple intelligent parking assist system cannot be operated.

      • When RHD/LHD cannot be judged, the simple intelligent parking assist system cannot be operated.

      • Availability of the stop and start system cannot be judged.

      • Clearance sonar cannot be operated.

      • Simple intelligent parking assist system operation is canceled (indicator is displayed on the combination meter assembly and the buzzer sounds).

      U0100

      U0142

      (Clearance warning ECU assembly)

      Steering Wheel Control


      • Checks the status of the steering sensor (spiral cable with sensor sub-assembly) and power steering ECU assembly and judges start/cancel of simple intelligent parking assist control. Also checks steering sensor (spiral cable with sensor sub-assembly) status and sends the steering angle signal to the power steering ECU assembly.

      		 Clearance warning ECU assembly Power steering ECU assembly Simple intelligent parking assist system operation is canceled. Simple intelligent parking assist system operation is canceled (indicator is displayed on the combination meter assembly and the buzzer sounds).

      U0126

      U0131

      (Clearance warning ECU assembly)

      Side Turn Signal Check


      • Checks side turn signal status and decides detection direction.

      		 Clearance warning ECU assembly Combination meter assembly Simple intelligent parking assist system operation is canceled. - -

      Stop and Start System


      • Stops the engine when the vehicle is stationary.

      		 Engine stop and start ECU

      • Air conditioning amplifier assembly

      • Brake actuator assembly

      • ECM

      • Power steering ECU assembly

      • Main body ECU (Multiplex network body ECU)

      • Airbag sensor assembly

      • Combination meter assembly

      • Clearance warning ECU assembly

      • When driving in eco drive mode, the engine starts.

      • When not driving in eco drive mode, eco drive cannot be performed.

      		 Stop and start cancel indicator light blinks.

      U0100

      U0121

      U0131

      U0140

      U0151

      U0155

      U0164

      U1110

      (Engine stop and start ECU)

      Engine Related Indicator Display


      • Estimates engine oil deterioration and displays a message etc., indicating replacement of the oil on the combination meter assembly.

      		 ECM Combination meter assembly Engine oil maintenance related items displayed on the combination meter assembly cannot be cleared.

      • Replacement warning is not displayed.

      • The message on the combination meter assembly remains displayed.

      		 -

      Electrical Load Control


      • Perform idle up according to electric load.

      		 ECM

      • Air conditioning amplifier assembly

      • Power steering ECU assembly

      • Main body ECU (Multiplex network body ECU)

      		 Idle up according to the electrical load is not performed. Engine idle speed changes. -

      Air Conditioning Cooperative Operation


      • Performs idle up according to compressor load.

      		 ECM Air conditioning amplifier assembly Air conditioning system does not use cooperative controls. Air conditioning system does not operate. -

      PTC Heater


      • Performs idle up when there is a heat demand signal that requires operation of the PTC heater.

      		 ECM Air conditioning amplifier assembly PTC heater does not operate.

      • Engine idle speed changes.

      • Heating performance deteriorates.

      • PTC heater does not operate.

      		 -

      Charge Control


      • Performs idle up according to charging request.

      		 ECM

      • Air conditioning amplifier assembly

      • Main body ECU (Multiplex network body ECU)

      • Idle up according to charging request is not performed.

      • Charging control is not prohibited.

      • Idle up according to charging request is not performed.

      • Tail lights flicker and blower airflow changes.

      		 -

      Neutral Control


      • Reduces engine load and performs idle up.

      		 ECM

      • Brake actuator assembly

      • Airbag sensor assembly

      		 Neutral control is not performed. -

      U0129

      (ECM)

      Coast Downshift


      • Changes coast downshift timing according to air conditioning load.

      		 ECM Air conditioning amplifier assembly Coast downshift does not occur. Coast downshift shock reduction performance deteriorates. -

      Eco Driving Indicator


      • Displays information to the driver to encourage eco-driving.

      		 ECM Combination meter assembly - No information is displayed. -

      Stop and Start Control


      • Starts and stops the engine using the stop and start control.

      		 ECM Engine stop and start ECU Stop and start control is not performed. Stop and start control does not operate.

      U1103

      (ECM)

      Eco Control

      (for Gasoline engine)


      • Adjusts throttle response in consideration of actual fuel economy.

      		 ECM

      • Air conditioning amplifier assembly

      • Main body ECU (Multiplex network body ECU)

      • Combination meter assembly

      		 Eco mode does not operate.

      • Indicator does not illuminate.

      • Eco mode does not operate.

      		 -

      Electronic Power Steering System


      • Calculates the current to be used for the steering assist according to the torque sensor value and vehicle speed, and then operates the motor.

      		 Power steering ECU assembly

      • ECM

      • Brake actuator assembly

      • Steering sensor (Spiral cable with sensor sub-assembly)

      • Power steering does not operate.

      • Control is performed temporarily with the steering assist amount set to that used when the vehicle speed is 100 km/h (62 mph).

      • The steering feel becomes worse (compensation control using the steering angle is stopped).

      		 EPS warning light illuminates.

      U0100

      U0129

      (Power steering ECU assembly)

      αB Control


      • Provides an assist to prevent the vehicle from skidding.

      		 Brake actuator assembly Power steering ECU assembly When CAN data of the brake actuator assembly becomes invalid during αB control, the control is stopped. EPS warning light illuminates.

      U0129

      (Power steering ECU assembly)

      Steering Assist Calculation


      • Changes the assist force according to the vehicle speed.

      		 Power steering ECU assembly Brake actuator assembly

      • Control continues temporarily with a set speed of 100 km/h (62 mph) as the system is unable to recognize the actual vehicle speed.

      • The steering wheel feels heavy below vehicle speeds of 100 km/h (62 mph) and feels light at vehicle speeds exceeding 100 km/h (62 mph).

      		 EPS warning light illuminates.

      U0129

      (Power steering ECU assembly)

      Assist Map Selection


      • Selects the assist map according to the destination information, engine type, etc.

      		 Power steering ECU assembly

      • Brake actuator assembly

      • ECM

      • Main body ECU (Multiplex network body ECU)

      • A temporary map is used to perform assist as an assist map cannot be selected according to vehicle specifications.

      • Steering feel may be unusual.

      • The frame used to select the assist map may change depending on the vehicle.

      		 EPS warning light illuminates.

      C1581

      (Power steering ECU assembly)

      Initialization and Zero Point Learning


      • Performs steering angle sensor initialization and zero point learning.

      		 Power steering ECU assembly

      • Brake actuator assembly

      • Airbag sensor assembly

      • Steering sensor (Spiral cable with sensor sub-assembly)

      		 Steering sensor initialization and zero point learning are not performed. EPS warning light illuminates.

      U0129

      (Power steering ECU assembly)

      Steering Assist Compensation Control


      • Provides steering assist with compensation amount based on vehicle speed.

      		 Power steering ECU assembly Brake actuator assembly Control is performed based on a default vehicle speed of approximately 100 km/h (62 mph). EPS warning light illuminates.

      U0129

      (Power steering ECU assembly)

      Entry Function


      • Entry lock/unlock

      • Performs entry illumination (interior illumination etc).

      • Main body ECU (Multiplex network body ECU)

      • Certification ECU (Smart key ECU assembly)

      • Main body ECU (Multiplex network body ECU)

      • Certification ECU (Smart key ECU assembly)

      • ECM

      • Combination meter assembly

      		 Entry unlock is performed again.

      • Entry lock/unlock or entry back door unlatch does not operate.

      • Warning functions (key confinement, key not in vehicle, key reminder, etc.) do not operate and key confinement prevention control does not operate.

      • Entry illumination does not operate.

      • Answer-back continues (maximum of 3 sets) when the doors are unlocked. (Only when the main body ECU (multiplex network body ECU) can receive a request signal from the certification ECU (smart key ECU assembly).)

      • Wrong entry warning is output.

      U0100

      U0142

      U0155

      (Certification ECU (Smart key ECU assembly))

      Wireless Function


      • Locks and unlocks doors etc. via remote operation.

      		 Main body ECU (Multiplex network body ECU)

      • Main body ECU (Multiplex network body ECU)

      • Certification ECU (Smart key ECU assembly)

      		 - Wireless lock and unlock do not operate. -

      Engine Switch Illumination Control


      • Operates the engine switch illumination in conjunction with the dome light illumination, etc.

      		 Certification ECU (Smart key ECU assembly)

      • Main body ECU (Multiplex network body ECU)

      • Certification ECU (Smart key ECU assembly)

      • Combination meter assembly

      • If the engine switch is not illuminated, it does not illuminate.

      • When the engine switch is illuminated due to the dome light, the illumination does not turn off.

      • When the DC cut fuse is disconnected and the engine switch illuminated due to the dome light, the illumination does not turn off.

      • If the engine switch is not illuminated, it does not illuminate.

      • When the engine switch is illuminated due to the dome light, the illumination does not turn off.

      • When the DC cut fuse is disconnected and the engine switch illuminated due to the dome light, the illumination does not turn off.

      U0142

      (Certification ECU (Smart key ECU assembly))

      Vehicle Speed Display


      • Displays the vehicle speed on the speedometer according to the vehicle speed signal from brake actuator assembly.

      		 Combination meter assembly Brake actuator assembly Control is performed based on signal value of 0.

      • The needle points at 0 km/h (0 mph).

      • Drive monitor calculation is stopped.

      U0129

      (Combination meter assembly)

      Tachometer


      • Displays information on the tachometer.

      		 Combination meter assembly ECM Control is performed based on signal value of 0.

      • The tachometer displays 0 rpm.

      • The drive monitor stops calculating.

      U0100

      (Combination meter assembly)

      Airbag Warning


      • Airbag warning light control.

      		 Combination meter assembly Airbag sensor assembly Control is performed based on signal value of "Active". Airbag warning light illuminates.

      U0151

      (Combination meter assembly)

      EPS Warning


      • EPS warning light control.

      		 Combination meter assembly Power steering ECU assembly Control is performed based on signal value of "Active". EPS warning light illuminates.

      U0131

      (Combination meter assembly)

      SLIP Warning


      • SLIP warning light control.

      		 Combination meter assembly Brake actuator assembly Control is performed based on signal value of "Active". SLIP warning light illuminates. -
      Engine Coolant Temperature Receiver Gauge Control Combination meter assembly ECM Control is performed based on signal value of 0. Needle of engine coolant temperature receiver gauge is at the middle or below. -

      Engine Start/Stop Switch (Power Source Mode Change)


      • Using start/stop switch signal as trigger, changes power source mode automatically and requests starter operation when conditions are met.

      		 Certification ECU (Smart key ECU assembly)

      • Main body ECU (Multiplex network body ECU)

      • ECM

      • Brake actuator assembly

      • Combination meter assembly

      • Engine stop and start ECU

      		 After the ignition switch operation, it always takes 1.2 seconds before power source mode changes to off.

      • A message urging engine start operation is not displayed when required.

      • Engine switch indicator blinks in amber.

      U0100

      U0129

      (Certification ECU (Smart key ECU assembly))

      Engine Start Control


      • Allows the engine to start by pressing the engine switch once. (Cranking hold)

      		 Certification ECU (Smart key ECU assembly) ECM Cranking is stopped when engine starting is judged based on an engine speed signal received via direct line. -

      U0100

      (Certification ECU (Smart key ECU assembly))