CAN COMMUNICATION SYSTEM FAIL-SAFE CHART


  1. FAIL-SAFE FUNCTION


    1. When communication fails in any of the main wires (communication lines) 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 table below shows the effects on each system when communication is impossible. For further details, refer to each system.

      System

      Function

      (Function Description)

      		 Control Master System Related Fail-safe Operation

      DTC

      (Driver Detectable)
      Engine control

      Engine control system indication

      (Assesses engine oil degradation, and lights the oil maintenance indicator lamp on the combination meter assembly.)

      		 ECM (for 1ND-TV) Combination meter assembly Meter indication cannot be cleared.

      Nothing

      (Meter indication cannot be cleared.)
      Engine control

      Electrical load control

      (Increases idle speed according to electrical load.)

      		 ECM Power steering ECU assembly The idle speed increase for an electrical load is not performed.

      Nothing

      (The idle speed changes.)
      Engine control

      Air conditioner-linked control

      (Idle speed increased according to compressor load.)

      (Controls air conditioner cutoff.)

      		 ECM Air conditioning amplifier assembly Air conditioner-linked control does not operate. (cannot idle up)

      Nothing

      (Air conditioning inoperative.)
      Engine control

      PTC heater

      (Increases idle speed according to requests from the PTC heater or the heater system.)

      		 ECM Air conditioning amplifier assembly PTC heater does not operate. (does not permit operations)

      Nothing

      (The idle speed changes. The heater function worsens. PTC heater does not operate.)
      Engine control

      Charging control

      (Performs idle up according to charging requests.)

      		 ECM Air conditioning amplifier assembly, Main body ECU (multiplex network body ECU), Certification ECU (smart key ECU assembly) The idle speed increase for a charge request is not performed.

      Nothing

      (The idle speed increase for a charge request is not performed.)
      Charge control is not prohibited.

      Nothing

      (Tail lights flicker and blower airflow changes.)
      Engine control

      ECO driving indicator

      (Informs the driver about ECO-driving status.)

      		 ECM (for 1NR-FE and 1NZ-FE) Combination meter assembly Indicator is turned off.

      Nothing

      (Detected by the status that the indicator is turned off.)
      Engine control

      Integrated control

      (Estimates the required torque from the driver's accelerator pedal control, regulates torque characteristics depending on the vehicle state, provides constant-speed drivability and improved starting ability, re-acceleration and feeling of acceleration.)

      		 ECM Skid control ECU (brake actuator assembly), Power steering ECU assembly Following performances are not operative: Stable constant-speed drivability, starting ability, re-acceleration ability and improved feeling of acceleration by estimating the required torque from the driver's accelerator pedal control and performing torque control according to the driving situation.

      Nothing

      (Following performances are not operative: Stable constant-speed drivability, starting ability, re-acceleration ability and improved feeling of acceleration by estimating the required torque from the driver's accelerator pedal control and performing torque control according to the driving situation.)
      Engine control

      ECO Control

      (Performs electronic throttle control according to actual fuel consumption.)

      		 ECM Air conditioning amplifier assembly, Combination meter assembly ECO mode does not operate.

      Nothing

      (Detected by failure of ECO mode operation.)
      Engine control

      ECT system indicators

      (Displays the shift lever position, switch position, and driving mode, etc. in the combination meter assembly.)

      		 ECM (for 1NR-FE and 1NZ-FE) Main body ECU (multiplex network body ECU), Combination meter assembly Cannot shift to the power or snow mode driving control.

      Nothing

      (Cannot shift to the power or snow mode driving control. Indicator light does not come on.)
      Engine control

      Neutral Control

      (Reduces the engine load and performs idle up.)

      		 ECM (for 1NR-FE and 1NZ-FE) Skid control ECU (brake actuator assembly) Neutral control does not operate.

      U0129

      (Nothing)
      Engine control

      Cruise control

      (Throttle valve position is adjusted automatically to maintain the vehicle speed without depressing the accelerator pedal.)

      		 ECM (for 1NR-FE and 1NZ-FE) Skid control ECU (brake actuator assembly), Combination meter assembly Nothing

      Nothing

      (Indicator light blinks.)
      Engine control

      Stop and start control

      (Stops and starts the engine with the stop and start control.)

      		 ECM (for 1NR-FE and 1NZ-FE) Engine stop and start ECU Stop and start control does not operate.

      U1103

      (Stop and start control does not operate.)
      Airbag

      TC DTC output service

      (Sends a DTC in response to a DTC output request from the combination meter assembly when receiving a signal from the ECM that the DLC3 TC terminal is on.)

      		 Airbag sensor assembly ECM When receipt of the TC signal is interrupted while receiving a signal from the ECM that the DLC3 TC terminal is on, the TC terminal is assumed to be off, and TC service is halted.

      Nothing

      (Nothing)
      Airbag

      Event data recorder (EDR)

      (When the conditions for recording on the event data recorder are met, stores data on vehicle speed, accelerator position, shift position, etc.)

      		 Airbag sensor assembly ECM, Skid control ECU (brake actuator assembly) Data is not recorded.

      Nothing

      (Nothing)
      Airbag

      Time stamp

      (Stores a DTC and time stamp information received from the main body ECU (multiplex network body ECU).)

      		 Airbag sensor assembly Main body ECU (multiplex network body ECU) When receiving a fail value or when confirming that transmission has been interrupted, switching to a unique internal ECU count is done and unique count identification is set.

      Nothing

      (Nothing)
      Airbag

      Trigger signal / Independence signal

      (Yaw rate sensor and deceleration sensor signal output)

      		 Airbag sensor assembly Skid control ECU (brake actuator assembly) Regular transmission

      Nothing

      (Nothing)
      VSC

      ABS control

      (Vehicle anti-locking for sudden stops.)

      		 Skid control ECU (brake actuator assembly) Nothing

      • Under control: After backup control to stabilize the vehicle behavior is completed, the normal brake is switched to and control is prohibited.

      • Not under control: Cannot start control.

      U0073

      (Complied with FMVSS126: Brake warning light comes on. ABS warning light comes on. Slip indicator light comes on.)
      Airbag sensor assembly

      U0124

      (Complied with FMVSS126: ABS warning light comes on. Slip indicator light comes on.)
      VSC

      VSC / TRC control

      (Suppresses vehicle body instability when slipping while turning, or when the vehicle wheels slip during acceleration.)

      		 Skid control ECU (brake actuator assembly) Nothing

      • Under control: After backup control to stabilize the vehicle behavior is completed, the normal brake is switched to and control is prohibited.

      • Not under control: Cannot start control.

      U0073

      (Complied with FMVSS126: Brake warning light comes on. ABS warning light comes on. Slip indicator light comes on.)
      ECM, Steering angle sensor (spiral cable sub-assembly)

      U0100, U0126

      (Complied with FMVSS126: Slip indicator light comes on.)
      Airbag sensor assembly

      U0124

      (Complied with FMVSS126: ABS warning light comes on. Slip indicator light comes on.)
      VSC

      Stop and start hill hold control (w/ Engine Stop and Start System)

      (Maintains brake fluid pressure while changing from pressing the brake pedal to pressing the accelerator to restart the engine, when the engine has been stopped with the stop and start control.)

      		 Skid control ECU (brake actuator assembly) Nothing

      • Under control: Control is continued and after normal control is completed, control is prohibited.

      • Not under control: Cannot start control.

      U0073

      (Complied with FMVSS126: Brake warning light comes on. ABS warning light comes on. Slip indicator light comes on.)
      ECM

      U0100

      (Complied with FMVSS126: Slip indicator light comes on.)
      Airbag sensor assembly

      U0124

      (Complied with FMVSS126: ABS warning light comes on. Slip indicator light comes on.)
      Steering angle sensor (spiral cable sub-assembly) Control is continued

      U0126

      (Complied with FMVSS126: Slip indicator light comes on.)
      Engine stop and start ECU Nothing

      Nothing

      (Nothing)
      Air Conditioning

      Air conditioning control

      (Performs engine speed compensation such as idle up, regulates air conditioning outlet airflow temperature / outlet switching / outlet airflow volume based on engine coolant temperature, adjusts engine coolant temperature mapping based on engine model, and changes compressor lock assessment values.)

      		 Air conditioning amplifier assembly ECM

      • Coolant signal during the ignition switch ON: Controlled with default value of 80°C.

      • Engine model during the ignition switch ON: Controlled with default value which differs according to vehicle models.

      • Not controlled without the ignition switch ON.

      U0100

      (Nothing)
      Air Conditioning

      Simple load control

      (Limits the simple electrical load control status according to the load control level.)

      		 Air conditioning amplifier assembly Power steering ECU assembly

      • Previous status held during the ignition switch ON. (when resetting: no load control.)

      • Not controlled without the ignition switch ON.

      U0131

      (Nothing)
      Air Conditioning

      Panel dimming control

      (Outputs dimming information to the LIN panel based on dimming information.)

      		 Air conditioning amplifier assembly Main body ECU (multiplex network body ECU)

      • Previous status held during the ignition switch ON. (when resetting: no load control.)

      • Not controlled without the ignition switch ON.

      U0142

      (Cannot switch between dimming and not dimming (after resetting, dimming status remains), Not IG-ON: Nothing.)
      Air Conditioning

      Destination determinate control

      (Changes A/C control patterns based on destination information.)

      		 Air conditioning amplifier assembly Main body ECU (multiplex network body ECU)

      • Previous status held during the ignition switch ON.

      • Not controlled without the ignition switch ON.

      U0142

      (Nothing)
      Air Conditioning

      External temperature compensation control

      (Switches the air conditioning system operation status and compensates the external temperature display output value according to the vehicle speed.)

      		 Air conditioning amplifier assembly Combination meter assembly

      • Speed signal input during the ignition switch ON : Controlled with the default value of 0 km/h.

      • Not controlled without the ignition switch ON.

      U0155

      (The matching reliability of the displayed external temperature to the actual external temperature is deteriorated. The suitability level of air conditioner outlet airflow compensation is reduced. Not IG-ON: Nothing.)
      Radio and Display

      Eco drive information

      (A function that displays fuel consumption per minute on a graph, and displays the history of total fuel consumption.)

      		 Radio and display receiver assembly ECM, Skid control ECU (brake actuator assembly) Stops the display update of fuel consumption per minute (fuel consumption per minute calculation) for the Eco drive screen (fuel consumption per minute screen). (Does not erase the history of fuel consumption per minute graph displayed up to that point.)

      U0100, U0129

      (The fuel consumption per minute graph on the Eco drive screen has not been updated for 1 minute or more.)
      Combination meter assembly Stops the update of the total fuel consumption display on the Eco drive screen (fuel consumption per defined distance).

      Nothing

      (The latest value on the fuel consumption per defined distance graph on the Eco drive screen is erased.)
      If the potential cruising distance is displayed on the Eco drive screen (fuel consumption per defined distance screen), erases the numerical section of the potential cruising distance due to transmission halting of the potential cruising distance data.

      U0155

      (The numerical section of the potential cruising distance on the fuel consumption per defined distance graph on the Eco drive screen is erased.)
      Radio and Display

      Destination determinate control

      (A function that assesses the destination based on destination symbols and package information, and selects the language and Time Zone for use in displays.)

      		 Radio and display receiver assembly Main body ECU (multiplex network body ECU) Determines the destination from the last value received (initial value if unable to receive any value thus far).

      U0140

      (The Time Zone and language selection screens are different from the destination.)
      Main body

      Door lock (w/ Rear Fog Light)

      (Lock / Unlock control (Key-linked, lock-in prevention, auto-locking, etc.))

      		 Main body ECU (multiplex network body ECU) Airbag sensor assembly When the ignition switch is ON, follows the last information prior to interruption. Additionally, key-linked operation is also permitted when the ignition switch is off.

      U0151

      (Nothing)
      Combination meter assembly The speed-sensitive automatic door lock operation is prohibited.

      U0155

      (Nothing)
      ECM

      • The speed-sensitive automatic door lock operation is prohibited.

      • The shift-linked automatic door lock operation is prohibited.

      U0100

      (Nothing)

      • The shift-linked automatic door lock operation is prohibited.

      • The shift-linked automatic door unlock operation is prohibited.

      • Automatic lock switching is prohibited.

      U0101

      (Nothing)
      Main body

      Alarm

      (Warning buzzer)

      		 Main body ECU (multiplex network body ECU) ECM, Certification ECU (smart key ECU assembly) Nothing

      U0100, U0120

      (Nothing)
      Main body

      Automatic Dimming of Display

      (Control of display illumination dimness)

      		 Main body ECU (multiplex network body ECU) Combination meter assembly

      • Conduct the display auto dimming control without the tail cancel status.

      • If the light sensor illumination signal value is less than the display dimming value, the in-room displays and indicators are dimmed.

      U0155

      (Nothing)
      Main body

      Illumination

      (Lighting control)

      		 Main body ECU (multiplex network body ECU) ECM, Certification ECU (smart key ECU assembly)

      • The dome light is turned off.

      • The interior foot light illumination is turned off.

      U0100, U0327

      (The dome light is not turned off immediately after the vehicle is left.)
      Main body

      Entry and start/Wireless

      (Smart / wireless control)

      		 Main body ECU (multiplex network body ECU) Certification ECU (smart key ECU assembly) Entry and start/wireless control does not operate.

      U0327

      (Detected by failure of entry lock/unlock operation.)
      Main body

      DRL control (w/ Rear Fog Light)

      (DRL control)

      		 Main body ECU (multiplex network body ECU) ECM DRL control operation fails.

      U0100

      (Detected by failure of DRL control.)
      EPS

      Electronic power steering system

      (Calculates the steering assist current from the torque sensor value and vehicle speed, and drives the motor.)

      		 Power steering ECU assembly ECM The power steering does not operate.

      U0100

      (EPS warning light comes on.)
      Skid control ECU (brake actuator assembly) Control is performed temporarily with the steering assist amount set to that used when the vehicle speed is 70 km/h.

      U0129

      (EPS warning light comes on.)
      Steering angle sensor (spiral cable sub-assembly) Feeling deteriorates (cancels compensation that uses information from the steering angle sensor).

      Nothing

      (Nothing)
      EPS

      αB control

      (Assists in preventing sideways skidding.)

      		 Power steering ECU assembly Skid control ECU (brake actuator assembly) αB control finishes when data becomes invalid while αB is being controlled.

      U0129

      (EPS warning light comes on.)
      EPS

      Assist calculation

      (Changes the amount of assist to steering operation based on vehicle speed.)

      		 Power steering ECU assembly Skid control ECU (brake actuator assembly)

      • Since vehicle speed recognition is not possible, control continues temporarily with the vehicle speed assumed to be 70 km/h.

      • When vehicle speed is less than 70 km/h, the steering feels heavy, and light when speed is in excess of 70 km/h.

      U0129

      (EPS warning light comes on.)
      EPS

      Assist map selection

      (Selects assist map based on destination, drive system (2WD, 4WD), engine variation, etc.)

      		 Power steering ECU assembly ECM, Skid control ECU (brake actuator assembly)

      • Since the assist map according to the vehicle model cannot be selected, steering assist is provided using a temporary map.

      • Steering feeling may not be normal.

      U0100, U0129

      (EPS warning light comes on.)
      EPS

      Center position learning

      (Learns the steering wheel angle center position.)

      		 Power steering ECU assembly ECM, Skid control ECU (brake actuator assembly) Does not learn the center position if the CAN system has malfunctions.

      U0129

      (EPS warning light comes on.)
      EPS

      Compensation control

      (Provides assist compensation based on vehicle speed.)

      		 Power steering ECU assembly ECM, Skid control ECU (brake actuator assembly) If CAN system has a malfunction (vehicle speed malfunction), the amount of control is regulated based on a temporary assumption that vehicle speed is 70 km/h.

      U0129

      (EPS warning light comes on.)
      Certification ECU

      Entry function

      (Performs smart locking / smart unlocking / smart back door unlatching / smart warning / smart illumination (dome lamp lighting, etc).)

      		 Certification ECU (smart key ECU assembly) Nothing Nothing

      Nothing

      (Smart locking, smart unlocking, smart back door unlatching failures / smart alarm failures (key lock-in, taking key out of vehicle, key reminder, etc.) / key lock-in prevention control failure / smart illumination failure.)
      Main body ECU (multiplex network body ECU) Retries smart unlocking.

      U0142

      (Answerback operation for unlocking doors continues (maximum 3 sets) (only when the main body ECU (multiplex network body ECU) was able to receive a request from the certification ECU (smart key ECU assembly).)
      Main body ECU (multiplex network body ECU), Combination meter assembly Nothing

      U0142, U0155

      (Smart alarm failures (key lock-in, taking key out of vehicle, key reminder, etc.), key lock-in prevention control failure.)
      Engine stop and start ECU Nothing

      U1103

      (An erroneous smart alarm is output.)
      ECM Maintain previous value.

      U0100

      (An erroneous smart alarm is output.)
      Certification ECU

      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)

      • The engine switch illumination is lit accompanying the dome light: It turns off.

      • The engine switch illumination is lit accompanying the panel illumination while D.C.C fuse is removed: It turns off.

      U0142

      (When the engine switch letter illumination is off: It does not light. When the engine switch letter illumination is lit by the panel lighting: It does not turn off. When the engine switch illumination is lit due to the dome light: It turns off. When the engine switch illumination is lit due to the panel illumination with D.C.C fuse removed: It turns off.)
      Certification ECU

      Push start

      (Switching power source)

      		 Certification ECU (smart key ECU assembly) Main body ECU (multiplex network body ECU) Nothing

      Nothing

      (The start operation is not displayed when necessary.)
      ECM Nothing

      U0100

      (Nothing)
      Skid control ECU (brake actuator assembly) Nothing

      U0129

      (Engine switch light blinks.)
      Certification ECU

      Starting control

      (A control that allows the engine to be started with a single push of the push start switch (cranking hold).)

      		 Certification ECU (smart key ECU assembly) ECM When CAN system has malfunctions, complete combustion signal NE is output using a direct line, and engine cranking hold operation is ended.

      U0100

      (Nothing)
      Engine Stop and Start ECU

      Stop and start system

      (Stops the engine when the vehicle is halted.)

      		 Engine stop and start ECU ECM (for 1NR-FE and 1NZ-FE), Airbag sensor assembly, Skid control ECU (brake actuator assembly), Air conditioning amplifier assembly, Main body ECU (multiplex network body ECU), Power steering ECU assembly, Combination meter assembly, Steering angle sensor (spiral cable sub-assembly)

      • Under operation: Restarting.

      • Not under operation: Stop and start operation prohibited.

      U0100, U0121,U0126,U0131, U0140, U0151, U0155, U0164

      (Stop and start light blinks.)
      Engine Stop and Start ECU

      Charging control

      (Performs idle up in response to a charging request.)

      		 Engine stop and start ECU ECM (for 1NR-FE), Air conditioning amplifier assembly, Main body ECU (multiplex network body ECU), Certification ECU (smart key ECU assembly) Does not perform idle up in response to a charging request.

      Nothing

      (Does not perform idle up in response to a charging request.)
      Does not prohibit charging control.

      Nothing

      (Tail light flickering, blower air flow volume changes.)
      Combination meter

      Vehicle speed indication

      (Speedometer display for vehicle speed signal from skid control ECU (brake actuator assembly)

      		 Combination meter assembly Skid control ECU (brake actuator assembly) Signal is treated as 0.

      U0129

      (Vehicle speed on the meter is indicated as 0 km/h. Drive monitor calculation stops.)
      Combination meter

      Tachometer

      (Tachometer display)

      		 Combination meter assembly ECM Signal is treated as 0.

      U0100

      (Tachometer rpm displayed as 0 rpm. Drive monitor calculation stops.)
      Combination meter

      Airbag warning

      (Airbag warning ON/OFF)

      		 Combination meter assembly Airbag sensor assembly Signal is treated as active.

      U0151

      (Airbag warning light comes on.)
      Combination meter

      EPS warning

      (EPS warning ON/OFF)

      		 Combination meter assembly Power steering ECU assembly Signal is treated as active.

      U0131

      (EPS warning light comes on.)
      Combination meter

      Slip indicator

      (Slip indicator ON/OFF)

      		 Combination meter assembly Skid control ECU (brake actuator assembly) Signal is treated as active.

      Nothing

      (Slip indicator light comes on.)
      Steering

      Steering angle sensor

      (Detects steering angle.)

      		 Steering angle sensor (spiral cable sub-assembly) Skid control ECU (brake actuator assembly) Transmits regularly.

      Nothing

      (Nothing)