CAN COMMUNICATION SYSTEM 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.

      		 Skid control ECU (Brake booster with master cylinder assembly) Airbag sensor 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

      U0124

      (Brake booster with master cylinder assembly)

      Vehicle Stability Control / Traction Control


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

      		 Skid control ECU (Brake booster with master cylinder assembly)

      • Airbag sensor assembly

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

      • Hybrid vehicle control ECU assembly

      • During control: After ending backup control (stabilizing the vehicle), 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.

      • Master warning light illuminates.

      U0073

      U0124

      U0126

      U0293

      (Brake booster with master cylinder 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 Hybrid vehicle control ECU assembly

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

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

      		 -

      U0293

      (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)

      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 Hybrid vehicle control ECU assembly Maintains the latest state (Maintained in normal condition after reset) -

      U0293

      (Air conditioning amplifier assembly)

      Leveling Control


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

      		 Headlight swivel ECU assembly

      • Skid control ECU (Brake booster with master cylinder assembly)

      • Main body ECU (Multiplex network body ECU)

      • Hybrid vehicle control ECU assembly

      • 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

      U0129

      U0142

      U0293

      (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)

      Fuel Consumption display


      • Displays graph of fuel consumption per minute and history of total fuel consumption.

      		 Radio and display receiver assembly

      • Skid control ECU (Brake booster with master cylinder assembly)

      • ECM

      • Hybrid vehicle control ECU assembly

      • Combination meter assembly

      When communication with ECM or skid control ECU is interrupted:


      • Display is not updated.

      When communication with combination meter is interrupted:


      • Display is not updated.

      • Numeric part of driveable mileage is cleared.

      		 -

      U0100

      U0129

      U0155

      U0293

      (Radio and display receiver assembly)

      HV energy flow display


      • Creates energy flow screen which indicates regeneration status and drive force transmission status.

      		 Radio and display receiver assembly Hybrid vehicle control ECU assembly If communication stops while the energy flow screen is displayed, the energy flow display disappears and the latest value is maintained for the SOC (state of charge) level display. -

      U0293

      (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

      • 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

      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) Interior lights turn off. The dome light does not turn off immediately after the doors are opened and closed.

      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)

      • Skid control ECU (Brake booster with master cylinder assembly)

      • Hybrid vehicle control ECU assembly

      		 The daytime running light control does not operate. -

      U0293

      (Main body ECU (Multiplex network body ECU))

      Display Dimming Control


      • Dims the parking assist pre support switch assembly indicator.

      		 Clearance warning ECU assembly Main body ECU (Multiplex network body ECU)

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

      • When communication is interrupted while the power switch is on (IG), 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.

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

      U0101

      (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 (a message is displayed on the multi-information display and the buzzer sounds).

      U0164

      (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 Hybrid vehicle control ECU assembly When communication is interrupted, simple intelligent parking assist system operation is canceled. Simple intelligent parking assist system operation is canceled (a message is displayed on the multi-information display and the buzzer sounds).

      U0293

      (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 Skid control ECU (Brake booster with master cylinder assembly) When communication is interrupted, simple intelligent parking assist system operation is canceled. -

      U0129

      (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)

      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

      • Main body ECU (Multiplex network body ECU)

      • Hybrid vehicle control ECU assembly

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

      • When RHD/LHD cannot be judged, operation is performed based on EEPROM memory.

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

      • Clearance sonar cannot be operated.

      • Simple intelligent parking assist system operation is canceled (a message is displayed on the multi-information display and the buzzer sounds).

      U0142

      U0293

      (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 (a message is displayed on the multi-information display 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. - -

      Moving Backward Judgment


      • Detects that the vehicle is moving backward using the yaw rate and acceleration sensor signal.

      		 Clearance warning ECU assembly Airbag sensor assembly Simple intelligent parking assist system operation is canceled. Simple intelligent parking assist system operation is canceled (a message is displayed on the multi-information display and the buzzer sounds).

      U0151

      (Clearance warning ECU assembly)

      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

      • Skid control ECU (Brake booster with master cylinder assembly)

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

      • Hybrid vehicle control ECU assembly

      • Power steering does not operate.

      • Assist force restricted.

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

      		 EPS warning light illuminates.

      U0129

      U0293

      (Power steering ECU assembly)

      αB Control


      • Provides an assist to prevent the vehicle from skidding.

      		 Skid control ECU (Brake booster with master cylinder assembly) Power steering ECU assembly When CAN data of the skid control ECU (brake booster with master cylinder 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 Skid control ECU (Brake booster with master cylinder assembly) Assist force restricted. 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

      • Skid control ECU (Brake booster with master cylinder assembly)

      • Hybrid vehicle control ECU assembly

      • 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

      U0293

      (Power steering ECU assembly)

      Initialization and Zero Point Learning


      • Performs steering angle sensor initialization and zero point learning.

      		 Power steering ECU assembly

      • Skid control ECU (Brake booster with master cylinder 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 Skid control ECU (Brake booster with master cylinder assembly) Assist force restricted. 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)

      • 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.

      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, unlock do not operate. -

      Power Switch Illumination Control


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

      		 Certification ECU (Smart key ECU assembly)

      • Main body ECU (Multiplex network body ECU)

      • Combination meter assembly

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

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

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

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

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

      • When the DC cut fuse is disconnected and the power 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 the skid control ECU (brake booster with master cylinder assembly).

      		 Combination meter assembly Skid control ECU (Brake booster with master cylinder 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)
      Hybrid System Indicator Display Combination meter assembly Hybrid vehicle control ECU assembly Control is performed based on signal value of 0. Needle of hybrid system indicator remains at the bottom.

      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 Skid control ECU (Brake booster with master cylinder 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. -

      Air Conditioning Control


      • Sends a signal from the air conditioning amplifier assembly to the hybrid vehicle control ECU assembly and from the hybrid vehicle control ECU assembly to the inverter for the air conditioning system.

      		 Air conditioning amplifier assembly Hybrid vehicle control ECU assembly Normal driving Air conditioning cooling operation is stopped.

      U0164

      (Hybrid vehicle control ECU assembly)

      Drive Torque Control


      • Controls the engine, MG1 and MG2 based on engine information received.

      		 Hybrid vehicle control ECU assembly ECM Vehicle drives using only the motor.

      • Master warning light illuminates.

      • MIL illuminates.

      U0100

      (Hybrid vehicle control ECU assembly)

      Regenerative Operation


      • Provides maximum amount of regeneration based on cooperative control with the ECB system.

      		 Hybrid vehicle control ECU assembly Skid control ECU (Brake booster with master cylinder assembly)

      • Regeneration is prohibited.

      • TRC operation is prohibited.

      		 Master warning light illuminates.

      U0129

      (Hybrid vehicle control ECU assembly)

      High voltage shut off control when the vehicle is damaged.


      • Receives the SRS collision detection signal and shuts off the system main relays.

      		 Hybrid vehicle control ECU assembly Airbag sensor assembly Normal driving Master warning light illuminates.

      U0151

      (Hybrid vehicle control ECU assembly)

      Cruise Control


      • Calculates demand drive force to maintain vehicle speed.

      		 Hybrid vehicle control ECU assembly

      • Skid control ECU (Brake booster with master cylinder assembly)

      		 Cruise control is canceled.

      • Displays messages on the multi-information display.

      • Master warning light illuminates.

      U0122

      (Hybrid vehicle control ECU assembly)

      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)

      • Hybrid vehicle control ECU assembly

      • Main body ECU (Multiplex network body ECU)

      • Combination meter assembly

      • Skid control ECU (Brake booster with master cylinder assembly)

      		 None A message is displayed on the multi-information display for 15 seconds when the power switch is turned from on (IG) to off.

      U0293

      (Certification ECU (Smart key ECU assembly))

      Pre-crash safety system


      • When the system determines that there is a high possibility of a collision with an obstacle in front of the vehicle, the system activates warnings and performs brake control.

      		 Pre-crash safety city sensor

      • Airbag sensor assembly

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

      • Skid control ECU (Brake booster with master cylinder assembly)

      • Combination meter assembly

      • Hybrid vehicle control ECU assembly

      		 Pre-crash safety system operation is canceled.

      • Buzzer sounds.

      • PCS warning light flashes.

      • Displays messages on the multi-information display.

      U0123

      U0126

      U0129

      U0293

      U023A

      Pre-crash safety city sensor

      Lane Departure Alert System


      • Warns when vehicle is deviating from its lane.

      		 Pre-crash safety city sensor

      • Airbag sensor assembly

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

      • Skid control ECU (Brake booster with master cylinder assembly)

      • Combination meter assembly

      • Hybrid vehicle control ECU assembly

      		 Lane departure and buzzer warning are canceled.

      • Buzzer sounds.

      • LDA indicator light turns off.

      • Displays messages on the multi-information display.

      U0123

      U0126

      U0129

      U0155

      U0293

      Pre-crash safety city sensor

      Road sign assist function


      • Identifies road signs while driving and displays them on the multi-information display.

      		 Pre-crash safety city sensor

      • Airbag sensor assembly

      • Skid control ECU (Brake booster with master cylinder assembly)

      • Hybrid vehicle control ECU assembly

      		 Road sign assist function is canceled. Displays messages on the multi-information display.

      U0123

      U0129

      U0293

      Pre-crash safety city sensor