Fail-Safe Chart [08/2015 - 10/2016]

FAIL-SAFE FUNCTION

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.

The following table shows the effects on each system when communication is impossible. (For further details, see Service Information 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	ECM	Control is performed based on default coolant temperature of 80°C (176°F).	-	U0100 (Air conditioning amplifier assembly)
Compressor Control Judges compressor lock according to engine speed.	Air conditioning amplifier assembly	ECM	Control is performed based on default engine speed of 0 rpm.	-	U0100 (Air conditioning amplifier assembly)
Simple Load Control Performs electric load control according to load control level signal.	Air conditioning amplifier assembly	Power steering ECU assembly	Load control is not performed.	-	U0131 (Air conditioning amplifier assembly)
Panel Dimming Control Outputs dimmer signal to LIN connected panels according to display dimmer signal.	Air conditioning amplifier assembly	Main body ECU (multiplex network body ECU)	Dimming mode and non-dimming mode cannot be switched.	-	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)
Insolation Correction Control Corrects air conditioning system control operation according to value of solar sensor.	Air conditioning amplifier assembly	Main body ECU (multiplex network body ECU)	Control is performed based on an insolation value of 0 after communication stop is confirmed.	-	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 Limits air conditioning system control.	Air conditioning amplifier assembly	ECM	Maintains the latest state (Maintained in normal condition after reset).	-	U0101 (Air conditioning amplifier assembly)
Door Lock Controls key linked and automatic door lock/unlock function, key confinement prevention function, etc.	Main body ECU (multiplex network body ECU)	ECM Combination meter assembly Airbag sensor assembly	Speed sensitive automatic lock control does not occur. Shift linked automatic lock 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))
Luggage Compartment Door Opener/Luggage Compartment Door Open Control Accepts luggage compartment door opener request.	Main body ECU (multiplex network body ECU)	ECM Combination meter assembly	Luggage compartment door does not open.	-	U0100 U0101 U0155 (Main body ECU (multiplex network body ECU))
Illumination Control	Main body ECU (multiplex network body ECU)	ECM Certification ECU (smart key ECU assembly)	Interior lights turn off. Mirror foot illumination is turned off. Footwell illumination is turned off. Interior lights do not turn off right after getting out of the vehicle.	-	U0101 U0327 (Main body ECU (multiplex network body ECU))
Seat and Mirror Control	Main body ECU (multiplex network body ECU)	Front power seat switch LH Outer mirror control ECU assembly (for driver side) Outer mirror control ECU assembly (for front passenger side) Multiplex tilt and telescopic ECU Combination meter assembly	Memory function does not operate. Mirrors cannot be adjusted.	-	U0155 U0199 U0200 U0208 U1115 (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))
Engine System Indicator Display Estimates whether injectors are clogged and requests that a message be displayed informing user that injectors need maintenance. Estimates whether oil has deteriorated and requests that a message be displayed informing user that oil needs to be replaced.	ECM	Combination meter assembly	System is unable to inform user that oil needs to be replaced or injectors need maintenance. Combination meter display cannot be cleared. System is unable to inform user of brake override system control status.	-	-
Electric Load Control Performs 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 electric load is not performed.	Not possible. (Idle speed changes.)	-
Air Conditioning Cooperative Operation Performs idle up according to compressor load. Performs air conditioning cut control.	ECM	Air conditioning amplifier assembly	Air conditioning system does not use cooperative controls. (Idle up is not performed.)	Air conditioning system does not operate.	-
Charge Control Performs idle up according to charging request.	ECM	Air conditioning amplifier assembly	Idle up according to charging request is not performed.	Taillights flicker and blower airflow changes.	-
Eco Control Adjusts throttle response in consideration of actual fuel economy.	ECM	Combination meter assembly	Eco mode does not operate.	-	-
ECT System Indicator Display Meter display. (Displays shift position, states of switches, system modes, etc.)	ECM	Combination meter assembly	Indicator light does not illuminate.	-	-
Neutral Control Reduces engine load and performs idle up.	ECM	Skid control ECU (brake actuator assembly) Yaw rate sensor	Neutral control is not performed.	-	-
Coast Downshift Timing Change According to Air Conditioning Load Delays upshifts according to warm-up request.	ECM	Air conditioning amplifier assembly	Coast downshift does not occur. Coast downshift shock reduction performance deteriorates.	-	-
Cruise Control Controls vehicle speed by adjusting throttle valve angle automatically.	ECM	Skid control ECU (brake actuator assembly) Driving support ECU assembly Combination meter assembly	Cruise control does not operate.	Displays messages on the multi-information display.	-
Power Steering Control Calculates assist current according to torque sensor value and vehicle speed and drives motor.	Power steering ECU assembly	ECM Skid control ECU (brake actuator assembly) Yaw rate sensor Steering sensor	Assist force restricted.	EPS warning light illuminates.	U0100 U0129 (Power steering ECU assembly)
VDIMα System Calculates current to be used for steering assist according to commanded value from VSC, and then operates motor.	Skid control ECU (brake actuator assembly) Power steering ECU assembly	Skid control ECU (brake actuator assembly)	VDIMα control is stopped.	-	-
VDIMβ System Calculates current to be used for steering assist according to commanded values from VSC and VGRS, and then operates motor.	Skid control ECU (brake actuator assembly) Front steering control ECU Power steering ECU assembly	ECM Skid control ECU (brake actuator assembly) Front steering control ECU Steering sensor	VDIMβ control is stopped.	EPS warning light illuminates. Displays messages on the multi-information display.	U0129 U0130 (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) Certification ECU (smart key ECU assembly)	Main body ECU (multiplex network body ECU) Combination meter assembly ECM	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.	U0100 U0142 U0155 (Certification ECU (smart key ECU assembly))
Entry Function/Wireless Control	Main body ECU (multiplex network body ECU)	Main body ECU (multiplex network body ECU)	Entry lock/unlock control is not possible.	-	-
Engine Switch Backlighting Control Turns on/off engine switch illumination linked with interior lights etc.	Certification ECU (smart key ECU assembly)	Main body ECU (multiplex network body ECU)	Engine switch backlighting does not illuminate according to interior lights operation.	-	U0142 (Certification ECU (smart key ECU assembly))
Security Indicator Display Function Displays immobiliser and security status.	Certification ECU (smart key ECU assembly)	Main body ECU (multiplex network body ECU)	Security indicator cannot display security status correctly. (Security indicator blinks or illuminates when in armed state or alarm sounding state.)	-	U0142 (Certification ECU (smart key ECU assembly))
Vehicle Speed Display	Combination meter assembly	Skid control ECU (brake actuator assembly)	None	Needle of speedometer remains at 0 km/h (0 mph). Drive monitor calculation is stopped.	U0129 (Combination meter assembly)
Tachometer Display	Combination meter assembly	ECM	None	Needle of tachometer remains at 0 rpm. Drive monitor calculation is stopped.	U0100 (Combination meter assembly)
Engine Coolant Temperature Receiver Gauge Control	Combination meter assembly	ECM	None	Needle of engine coolant temperature receiver gauge is at the middle or below.	-
Meter Display Displays vehicle condition and controls indicator lights.	Combination meter assembly	ECM Skid control ECU (brake actuator assembly) Airbag sensor assembly Main body ECU (multiplex network body ECU) Power steering ECU assembly Front steering control ECU Headlight leveling ECU assembly Driving support ECU assembly Lane departure warning camera 4WD ECU assembly	Lights do not illuminate or lights remain illuminated.	Abnormal light operation.	U0100 U0129 U0130 U0131 U0142 U0151 U0182 U023A U1104 (Combination meter assembly)
Buzzer Controls sounding of buzzer for various functions.	Combination meter assembly	Main body ECU (multiplex network body ECU) Airbag sensor assembly Skid control ECU (brake actuator assembly) Power steering ECU assembly ECM	Buzzer stops sounding or does not sound.	None	U0100 U0129 U0131 U0151 (Combination meter assembly)
Destination Identification Identifies destination based on destination and destination package information, and selects the time zone and language used for the display.	Combination meter assembly	Main body ECU (multiplex network body ECU)	None	-	U0142 (Combination meter assembly)
Linking-up with Multi-information Display Displays navigation, audio, telephone, etc.	Combination meter assembly	Radio receiver assembly	None	-	U0163 (Combination meter assembly)
AWD Control Controls torque distribution to the front and rear wheels.	4WD ECU assembly	ECM Steering sensor Skid control ECU (brake actuator assembly)	Front to rear torque split is fixed at 3:7 and drivability changes. AWD control is prohibited. Control continues by maintaining previous values. Control continues, but feedback of speed difference between front and rear wheels is prohibited.	4WD warning light illuminates.	U0073 U0100 U0126 U0129 (4WD ECU assembly)
ABS Control	Skid control ECU (brake actuator assembly)	Yaw rate 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 illuminates. ABS warning light illuminates. SLIP indicator illuminates.	U0073 U0124 (Skid control ECU (brake actuator assembly))
VSC/TRAC/VDIM Control	Skid control ECU (brake actuator assembly)	ECM Yaw rate sensor Steering sensor Front steering control ECU	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 illuminates. ABS warning light illuminates. SLIP indicator illuminates.	U0073 U0100 U0124 U0126 U0130 (Skid control ECU (brake actuator assembly))
Hill-start Assist Control Maintains brake pressure for 2 seconds when the brake pedal has been depressed further after stopping the vehicle.	Skid control ECU (brake actuator assembly)	ECM Yaw rate sensor Steering sensor	When control is being performed: 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 illuminates. ABS warning light illuminates. SLIP indicator illuminates.	U0073 U0100 U0124 U0126 (Skid control ECU (brake actuator assembly))
Headlight Leveling Control (Headlight Control) Adjusts headlights vertical aiming according to wheel speed and vehicle pitch angle determined using vehicle height sensor.	Headlight leveling ECU assembly	Skid control ECU (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.	Displays messages on the multi-information display.	U0129 U0142 (Headlight leveling ECU assembly)
VGRS Control Changes the steering gear ratio according to the vehicle speed information and steering angle.	Front steering control ECU	ECM Yaw rate sensor Steering sensor Power steering ECU assembly Skid control ECU (brake actuator assembly) Combination meter assembly	VGRS control is stopped.	Displays messages on the multi-information display.	U0100 U0101 U0126 U0129 U0131 (Front steering control ECU)
AVS Control Controls the variable damping force according to road and driving conditions.	Absorber control ECU	ECM Yaw rate sensor Front steering control ECU Radio receiver assembly Skid control ECU (brake actuator assembly)	Continues to control the damping force. Interrupts damping force control after moving front absorber control actuators and rear absorber control actuators to the 9th step. Controls continue except roll control.	-	U0100 U0101 U0122 U0124 U0126 U0130 (Absorber control ECU)
Air Conditioning Control Controls air conditioning functions such as set temperature adjustment, air outlet selection, etc. by operating LEXUS display audio controller or Remote Touch.	Radio 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. Air conditioning functions are prohibited.	Displays messages on the multi-information display.	U0073 U0164 (Radio receiver assembly)
Intuitive Parking Assist System Setting/Notification Controls settings for clearance sonar screen notifications which are set by operating Remote Touch, displays sonar status and plays voice warnings.	Radio receiver assembly	ECM Clearance warning ECU assembly	Display updating is stopped.	-	U0073 U0100 U1110 (Radio receiver assembly)
Fuel Consumption Display Displays graph of fuel consumption per minute and history of total fuel consumption.	Radio receiver assembly	ECM Skid control ECU (brake actuator 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 (Radio receiver assembly)
Destination Identification Identifies destination based on destination and destination package information, and selects the time zone and language used for the display.	Radio 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 receiver assembly)
Time Stamp Function Matches the relative time from the main body ECU with the absolute time acquired from the GPS.	Radio receiver assembly	Main body ECU (multiplex network body ECU)	None	-	U0073 U0140 (Radio receiver assembly)
Tire Pressure Monitoring System Receives information from TPMS ECU to display air pressure, tire location and system status.	Radio receiver assembly	Main body ECU (multiplex network body ECU)	None	-	U0073 (Radio receiver assembly)
Power Tilt and Power Telescopic Steering Column Control Starts steering wheel auto return or auto away based on an engine switch on/off signal or equivalent. Memorizes and recalls selected driving position according to memory switch operation. Moves steering wheel to selected position according to manual switch operation on steering column cover.	Multiplex tilt and telescopic ECU	Main body ECU (multiplex network body ECU) Front power seat switch LH	Driving position memory function is prohibited. Auto away/return function is prohibited.	-	U0142 U0208 (Multiplex tilt and telescopic ECU)
Seat Position Memory System Controls the seat position based on operation conditions.	Front power seat switch LH	Main body ECU (multiplex network body ECU) ECM Combination meter assembly Multiplex tilt and telescopic ECU	Controls the seat position based on operation conditions.	-	-
Illumination Control Controls illumination of lights based on courtesy switch information and interior light information.	Outer mirror control ECU assembly (for driver side) Outer mirror control ECU assembly (for front passenger side)	Main body ECU (multiplex network body ECU)	Mirror foot illumination is turned off.	-	U0142 (Outer mirror control ECU assembly)
Mirror Surface Adjustment	Outer mirror control ECU assembly (for driver side) Outer mirror control ECU assembly (for front passenger side)	Main body ECU (multiplex network body ECU)	Mirror surface position cannot be memorized or recalled.	-	U0142 (Outer mirror control ECU assembly)
Mirror Heaters	Outer mirror control ECU assembly (for driver side) Outer mirror control ECU assembly (for front passenger side)	Main body ECU (multiplex network body ECU) Air conditioning amplifier assembly	Mirror heaters do not operate.	-	U0142 (Outer mirror control ECU assembly)
Mirror Retract/Return Operation Controls retract/return operation of the outer mirrors based on signals such as mirror switch signal from main body ECU (multiplex network body ECU).	Outer mirror control ECU assembly (for driver side) Outer mirror control ECU assembly (for front passenger side)	Main body ECU (multiplex network body ECU)	Mirrors cannot be retracted or returned.	-	-
Reverse-shift Linked Door Mirror Operation	Outer mirror control ECU assembly (for driver side) Outer mirror control ECU assembly (for front passenger side)	Main body ECU (multiplex network body ECU)	Reverse-shift linked door mirror operation.	-	U0142 (Outer mirror control ECU assembly)
Mirror Surface Position Memory and Recall	Outer mirror control ECU assembly (for driver side) Outer mirror control ECU assembly (for front passenger side)	Main body ECU (multiplex network body ECU)	Mirror surface position cannot be memorized or recalled.	-	U0142 (Outer mirror control ECU assembly)
Seat Memory Switch Signal Forwarding Transmits memory switch signal via the CAN bus.	Main body ECU (multiplex network body ECU)	Outer mirror control ECU assembly (for driver side) Outer mirror control ECU assembly (for front passenger side)	Seat position memory settings cannot be memorized or recalled.	-	-
Dynamic Radar Cruise Control System Accelerates or decelerates the vehicle to maintain the distance to the vehicle ahead.	Driving support ECU assembly	ECM Yaw rate sensor Steering sensor Skid control ECU (brake actuator assembly)	Active cruise control is canceled. Fail-safe function operates only during active cruise control.	Warning message is displayed or cruise control indicator illuminates in yellow (when cruise control main switch is on). Buzzer sounds (cycle: 0.2 sec., number of times buzzer sounds: 2).	U0100 U0125 U0126 U0129 (Driving support ECU assembly)
Pre-collision System Controls the brakes immediately before a crash.	Driving support ECU assembly	ECM Yaw rate sensor Steering sensor Skid control ECU (brake actuator assembly) Main body ECU (multiplex network body ECU)	Control stops.	Displays messages on the multi-information display. PCS indicator light flashes.	U0100 U0125 U0129 U0142 (Driving support ECU assembly)
Intuitive Parking Assist System Control Judges vehicle speed.	Clearance warning ECU assembly	Combination meter assembly	Obstacle detection is stopped.	-	U0155 (Clearance warning ECU assembly)
Shift Position Judgment Uses received shift position signal as a clearance sonar detection operation condition.	Clearance warning ECU assembly	ECM	Control operates with the default shift position (P).	-	U0101 (ECM)
Voice Warning Availability Confirmation Uses destination code and steering wheel information for determining availability of voice warning for clearance sonar.	Clearance warning ECU assembly	Main body ECU (multiplex network body ECU)	Assumes that there is no voice warning.	-	-
Lane Departure Alert System Warns when vehicle is deviating from its lane.	Lane departure warning camera	Main body ECU (multiplex network body ECU) ECM Combination meter assembly Skid control ECU (brake actuator assembly) Yaw rate sensor Driving support ECU assembly	Lane departure and buzzer warning are canceled.	Displays messages on the multi-information display.	U0101 U0104 U0123 U0129 U0142 U0155 (Lane departure warning camera)
Automatic High Beam System Controls high beam on/off.	Lane departure warning camera	ECM Main body ECU (multiplex network body ECU) Skid control ECU (brake actuator assembly) Yaw rate sensor	Maintains the same condition.	Displays messages on the multi-information display.	U0101 U0123 U0129 U0142 (Lane departure warning camera)
Blind Spot Monitor Control Detects vehicle in blind spot of adjacent lane and informs driver.	Blind spot monitor sensor LH	ECM Skid control ECU (brake actuator assembly) Steering sensor Main body ECU (multiplex network body ECU)	None	Displays messages on the multi-information display.	U0100 U0126 U0129 U0142 (Blind spot monitor sensor LH)
Parking Assist Monitor Monitors the shift position signal, steering angle signal and vehicle speed, and displays the predicted path guide lines on the screen based on the steering angle when reversing.	Rear television camera assembly	ECM Steering sensor Skid control ECU (brake actuator assembly) Main body ECU (multiplex network body ECU) Front steering control ECU Clearance warning ECU assembly Radio receiver assembly Power steering ECU assembly	Parking assist monitor function is prohibited.	Predicted path guide lines are not displayed. All guide lines and the clearance sonar icon are not displayed.	U0100 U0126 U0129 U0130 U0131 U0140 U0163 U1110 (Rear television camera assembly)
Lexus Enform Remote Vehicle Status Report	Telematics transceiver	Combination meter assembly Main body ECU (multiplex network body ECU)	Function is disabled.	Notification displayedon smartphone via the application.	U0142 U0155 (Telematics transceiver)
Lexus Enform Remote Guest Driver Monitor	Telematics transceiver	Combination meter assembly	Function is disabled.	Notification displayedon smartphone via the application.	U0155 (Telematics transceiver)
Lexus Enform Remote Vehicle Status Alerts	Telematics transceiver	Main body ECU (multiplex network body ECU)	Function is disabled.	Notification displayedon smartphone via the application.	U0142 (Telematics transceiver)
Lexus Enform Remote Remote Engine Start and Stop	Telematics transceiver	Combination meter assembly Main body ECU (multiplex network body ECU) Certification ECU (smart key ECU assembly)	Function is disabled.	Notification displayedon smartphone via the application.	U0142 (Telematics transceiver)
Lexus Enform Remote Remote Door Lock and Unlock	Telematics transceiver	Combination meter assembly Main body ECU (multiplex network body ECU) Certification ECU (smart key ECU assembly)	Function is disabled.	Notification displayedon smartphone via the application.	U0142 (Telematics transceiver)