CAN COMMUNICATION SYSTEM(w/o Toyota Safety Sense) 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)

      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 Power management control ECU Control is performed based on default coolant temperature of 80°C (176°F). -

      U0293

      (Air conditioning amplifier assembly)

      Panel dimming control


      • Outputs dimming information to LIN panel based on display dimming information

      		 Air conditioning amplifier assembly Main body ECU (Multiplex network body ECU) Maintains the previous state (After reset, set to dim). Cannot change between dim / not dim (After reset, fixed to dim mode).

      U0142

      (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 Control


      • Displays the set temperature, air outlet selection, etc.

      		 Radio and display receiver assembly Air conditioning amplifier assembly

      • Air conditioning system indicators turn off.

      • If set temperature is shown on multi-information display or multi-display, set temperature display turns off.

      		 Displays messages on the multi-information display.

      U0073

      U0164

      (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

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

      • ECM

      • Combination meter assembly

      • Power management control ECU

      • Update of the per-minute fuel consumption display (per minute fuel consumption calculation) on the navigation Eco screen (per-minute fuel consumption screen) is stopped.

      • When drivable mileage is displayed on the navigation Eco screen, the displayed drivable mileage turns off due to data communication stop.

      		 -

      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

      • Power management control ECU

      • ECM

      		 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. -

      U0100

      U0293

      (Radio and display receiver assembly)

      Destination identification


      • Identifies destination bases 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 information received before communication is interrupted. Time zone and language selection screen are different from actual destination.

      U0140

      (Radio and display receiver assembly)

      Vehicle Customization Function


      • Allows changing of operation and control conditions for vehicle functions via multi-display operation.

      		 Radio and display receiver assembly

      • Main body ECU (multiplex network body ECU)

      • Air conditioning amplifier assembly

      • Certification ECU (smart key ECU assembly)

      • Customization via multi-display is not possible, but customization via main body ECU is possible.

      • When an application that uses remote communication is activated (customization/remote diagnosis), the process will be performed regardless of meter ECU remote communication permit/prohibit state.

      		 Related customization items are not displayed or do not change to set values.

      U0073

      (Radio and display receiver assembly)

      Display automatic dimming


      • Display dimming control

      		 Main body ECU (Multiplex network body ECU) Combination meter assembly Performs automatic display dimming when not in tail cancel mode. When light sensor brightness signal value is less than display dimming value, interior display/indicator brightness is dimmed. -

      U0155

      (Main body ECU (Multiplex network body ECU))

      Illumination control


      • Turns on the interior lights when the smart key is brought near the vehicle

      		 Main body ECU (Multiplex network body ECU) Smart key ECU assembly (Certification ECU) Interior lights turn off. -

      U0327

      (Main body ECU (Multiplex network body ECU))
      Entry function/wireless control Smart key ECU assembly (Certification ECU) 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

      • Power management control ECU

      		 Daytime running light control is not possible. -

      U0100

      U0293

      (Main body ECU (Multiplex network body ECU))

      Drive torque control


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

      		 Power management control ECU ECM Vehicle drives using only the motor

      • Displays messages on the multi-information display

      • MIL illuminates.

      U0100

      (Power management control ECU (Hybrid control system))

      Regenerative operation


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

      		 Power management control ECU Brake booster with master cylinder assembly (Skid control ECU) Regeneration is prohibited.

      • Displays messages on the multi-information display

      • MIL illuminates.

      • Brake warning Light illuminates.

      U0129

      (Power management control ECU (Hybrid control system))

      High voltage shut off control when the vehicle is damaged


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

      		 Power management control ECU Airbag sensor assembly Normal driving Displays messages on the multi-information display

      U0151

      (Power management control ECU (Hybrid control system))

      HV system power processing


      • Monitors whether IG2 is stuck ON based on IG2 information from the power management control ECU

      		 Power management control ECU (Hybrid control system) Power management control ECU (Power management control CPU)

      • Normal driving

      • Ignition switch turns off 10 seconds after the vehicle is stopped and shift lever is moved to P

      		 Displays messages on the multi-information display

      U1107

      (Power management control ECU (Hybrid control system))

      Air conditioning control


      • Sends a signal from the air conditioning amplifier assembly to the power management control ECU (HV CPU) and from the power management control ECU (HV CPU) to the inverter for the air conditioning system.

      		 Air conditioning amplifier assembly Power management control ECU Air conditioning cooling operation is stopped. -

      U0164

      (Power management control ECU)

      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

      		 Power management control ECU (Power management control CPU)

      • Main body ECU (Multiplex network body ECU)

      • Combination meter assembly

      • Power management control ECU (Hybrid control system)

      		 None -

      U0140

      U0155

      U0293

      Power management control ECU (Power management control CPU)

      Cruise control


      • Calculates demand drive force to maintain vehicle speed

      		 Power management control ECU Brake booster with master cylinder assembly (Skid control ECU) Cruise control is canceled.

      • Displays messages on the multi-information display

      • Master warning light turns on.

      U0122

      (Power management control ECU)

      Charge control


      • Performs idle up according to charging request

      		 Power management control ECU Air conditioning amplifier assembly Idle up according to charging request is not performed. Taillights flicker and blower airflow changes. -

      Power steering control


      • Calculates assist current according to torque sensor value and vehicle speed and drives motor

      		 Power steering ECU assembly

      • Power management control ECU

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

      • Control is performed based on default assist current for a vehicle speed of 70 km/h (43 mph).

      • Drivability degrades (compensation control using steering angle is stopped).

      		 EPS warning light illuminates.

      U0129

      U0293

      (Power steering ECU assembly)

      Steering assist calculation


      • Changes assist force based on vehicle speed

      		 Power steering ECU assembly Brake booster with master cylinder assembly (Skid control ECU) Control continues based on a default speed of 70 km/h (43 mph) because vehicle speed is unrecognizable. EPS warning light illuminates.

      U0129

      U0293

      (Power steering ECU assembly)
      Steering assist start judgment Power steering ECU assembly

      • Power management control ECU

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

      When a communication stop of power management control ECU communication occurs:


      • Assist starts when the vehicle speed is 0.1 km/h (0.06 mph) or more.

      When a communication stop of the power management control ECU or brake booster with master cylinder assembly (skid control ECU) occurs:


      • Control continues based on a default vehicle speed of 70 km/h (43 mph)

      		 EPS warning light illuminates.

      U0129

      U0293

      (Power steering ECU assembly)

      Assist map selection


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

      		 Power steering ECU assembly Power management control ECU Default map is used to assist because proper assist map cannot be selected. (Steering feel may be different.) EPS warning light illuminates.

      C1581

      (Power steering ECU assembly)

      Steering assist compensation control


      • Provides steering assist with compensation amount based on vehicle speed

      		 Power steering ECU assembly Brake booster with master cylinder assembly (Skid control ECU) Control is performed based on a default vehicle speed of approximately 70 km/h (43 mph). EPS warning light illuminates.

      U0129

      (Power steering ECU assembly)

      Steering/steering angle sensor initialization and zero point learning


      • Performs steering/ steering angle sensor initialization and zero point learning

      		 Power steering ECU assembly

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

      • Spiral cable with sensor subassembly (Steering angle sensor)

      • Airbag sensor assembly (built-in type yaw rate sensor)

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

      U0129

      (Power steering ECU assembly)

      Entry function


      • Entry lock/unlock, entry luggage compartment open

      • Warning

      • Performs entry illumination (Interior illumination etc)

      • Main body ECU (Multiplex network body ECU)

      • Smart key ECU assembly (Certification ECU)

      • Main body ECU (Multiplex network body ECU)

      • Combination meter assembly

      		 Entry unlock is performed again.

      • Entry lock/unlock or entry luggage compartment open does not operate.

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

      • Entry illumination does not operate.

      U0327

      (Main body ECU (Multiplex network body ECU))

      U0142

      U0155

      (Smart key ECU assembly (Certification ECU))

      Wireless function


      • Locks and unlocks doors etc. via remote operation

      		 Main body ECU (Multiplex network body ECU) Smart key ECU assembly (Certification ECU) Wireless lock, unlock and luggage compartment opener do not operate. -

      U0142

      (Smart key ECU assembly (Certification ECU))

      Power switch backlighting control


      • Turns on/off power switch illumination linked with interior lights etc.

      		 Smart key ECU assembly (Certification ECU) Main body ECU (Multiplex network body ECU) Power switch backlighting does not illuminate according to interior lights operation -

      U0142

      (Smart key ECU assembly (Certification ECU))
      Vehicle speed display Combination meter assembly Brake booster with master cylinder assembly (Skid control ECU) Speedometer is controlled based on a default vehicle speed of 0 km/h (0 mph).

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

      • Drive monitor calculation is stopped.

      U0129

      (Combination meter assembly)
      HV indicator display Combination meter assembly Power management control ECU HV indicator turns off -

      U0100

      (Combination meter assembly)

      Airbag

      (Airbag warning light control)

      		 Combination meter assembly Airbag sensor assembly None Airbag warning light illuminates.

      U0151

      (Combination meter assembly)

      EPS warning

      (EPS warning light control)

      		 Combination meter assembly Power steering ECU assembly None EPS warning light illuminates.

      U0131

      (Combination meter assembly)

      SLIP warning

      (SLIP warning light control)

      		 Combination meter assembly Brake booster with master cylinder assembly (Skid control ECU) None SLIP indicator illuminates.

      U0129

      (Combination meter assembly)

      HV drive guide display


      • Displays EV conditions

      		 Combination meter assembly ECM EV condition display turns off -

      U0100

      (Combination meter assembly)
      ABS/TRC/VSC control Brake booster with master cylinder assembly (Skid control ECU)

      • Power management control ECU

      • Airbag sensor assembly (built-in type yaw rate sensor)

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

      • When control is being performed: When back-up control (vehicle behavior stabilization) is complete, braking returns to normal operation and further control is prohibited.

      • When control is not being performed: Control will not be started.

      • Brake warning light (red) illuminates.

      • ABS warning light illuminates.

      • SLIP indicator illuminates.

      • Brake warning light (yellow) illuminates.

      U0073

      U0123

      U0124

      U0126

      U0293

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

      HAC3 control


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

      		 Brake booster with master cylinder assembly (Skid control ECU)

      • Power management control ECU

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

      • Airbag sensor assembly (built-in type yaw rate sensor)

      • When control is being performed: Once control (depressurization control) has completed, further hill-start assist control is prohibited.

      • When control is not being performed: Hill-start assist control does not start.

      • Brake warning light (red) illuminates.

      • ABS warning light illuminates.

      • SLIP indicator illuminates.

      • Brake warning light (yellow) illuminates.

      U0073

      U0123

      U0124

      U0126

      U0293

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

      Hybrid regenerative operation


      • Regenerative cooperative control with the HV system

      		 Brake booster with master cylinder assembly (Skid control ECU)

      • Power management control ECU

      • Airbag sensor assembly (built-in type yaw rate sensor)

      • When control is being performed: HV cooperative control is continued based on the latest value and gradually decreased. After this, HV cooperative control is prohibited.

      • When control is not being performed: HV cooperative control does not start.

      • Brake warning light (red) illuminates.

      • ABS warning light illuminates.

      • SLIP indicator illuminates.

      • Brake warning light (yellow) illuminates.

      U0073

      U0123

      U0124

      U0293

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