Toyota Yaris: Can Communication System / Fail-safe Chart

Toyota Yaris XP210 (2020-2024) Reapir and Service Manual / Power Source & Network / Networking / Can Communication System / Fail-safe Chart

FAIL-SAFE CHART

FAIL-SAFE FUNCTION

(a) 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.

(b) 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 (Main ECU to determine controls)	System Related	Fail-safe Operation	Driver Detectable	DTC Detection (ECU that stored DTC)
Engine System Indicator Display Estimates whether injectors are clogged and requests that a message be displayed informing user that injectors need maintenance. Estimates oil deterioration, and displays oil replacement display on combination meter assembly.	ECM	Combination meter assembly	-	Combination meter assembly display cannot be cleared.	-
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)	Does not perform idle up according to the electrical load.	Engine 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-linked control does not operate. (Unable to idle up.)	Air conditioning system does not operate.	-
PTC Heater Performs idle up according to requests from the PTC heater (including coolant heater) or heater system	ECM	Air conditioning amplifier assembly	PTC heater does not operate (not permitted).	Engine idle speed changes. Heating performance deteriorates. PTC heater does not operate.	-
Charging Control Performs idle up according to charging requests.	ECM	Air conditioning amplifier assembly Main body ECU (multiplex network body ECU)	Idle up according to charging requests is not performed. Charging control is not prohibited.	Taillights flicker and blower airflow changes.	-
Eco Control Performs electronic throttle control optimal for fuel economy.	ECM	Air conditioning amplifier assembly Main body ECU (multiplex network body ECU) Combination meter assembly	Eco-mode does not operate.	Combination meter assembly display cannot be cleared.	-
AI-SHIFT Control Controls A/T to improve engine brake force and acceleration feel.	ECM	Brake actuator assembly	AI-SHIFT control does not operate	-	-
Cruise Control Adjusts engine throttle valve position automatically to maintain vehicle speed.	ECM	Forward recognition camera Combination meter assembly Brake actuator assembly	Cruise control does not operate.	-	-
Timestamp Memorizes the timestamp informationreceived from the central gateway ECU [networkgateway ECU] together with the DTC.	Airbag sensor assembly	Central gateway ECU (network gateway ECU)	-	-	-
	Airbag sensor assembly	Combination meter assembly	-	-	-
Event Data Recorder (EDR) Records conditions, such as the vehicle speed, the amount the accelerator is depressed, and the shift position when the event data recorder recording conditions are met.	Airbag sensor assembly	ECM Steering sensor Brake actuator assembly Main body ECU (multiplex network body ECU) Central gateway ECU (network gateway ECU) Forward recognition camera Millimeter wave radar sensor assembly Power steering ECU assembly Combination meter assembly	-	-	-
Drive Data Recorder (DDR) Records conditions such as the vehicle speed, the amount the accelerator is depressed, and the shift position when the drive data recorder recording conditions are met.	Airbag sensor assembly	Central gateway ECU (network gateway ECU) Forward recognition camera Millimeter wave radar sensor assembly ECM Power steering ECU assembly Combination meter assembly Steering sensor Brake actuator assembly	-	-	-
AACN Sends data stored by the event data recorder to the emergency call service.	Airbag sensor assembly	Main body ECU (multiplex network body ECU) Combination meter assembly Brake actuator assembly	-	-	-
Prevention-linked Obtains information from the PCS and uses it for side airbag eployment control.	Airbag sensor assembly	Forward recognition camera Millimeter wave radar sensor assembly	-	SRS warning light illuminates.	U023587 U023A87 U110487 (Airbag sensor assembly)
Electric Power Steering 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	Brake actuator assembly ECM Steering sensor	Assist force restricted. The steering feel becomes worse (compensation control using the steering angle is stopped).	Master warning light illuminates. Displays messages on the multi-information display.	U010087 U012987 (Power steering ECU assembly)
VDIMα System Calculates the current to be used for the steering assist according to the command value from the brake actuator assembly, and then operates the motor.	Brake actuator assembly	Power steering ECU assembly	Control stops.	-	-
Lane Tracing Assist System Calculates the current to be used for assist according to the commanded torque value from the forward recognition camera and then operates the motor.	Forward recognition camera	Power steering ECU assembly	Control stops.	-	U023A87 (Power steering ECU assembly)
Assist Map Selection Selects proper assist map according to destination, engine type, etc.	Power steering ECU assembly	Brake actuator assembly ECM Main body ECU (multiplex network body ECU)	Default map is used to assist because proper assist map cannot be selected. (Steering feel may be different.)	EPS warning light (red) illuminates.	C158151 (Power steering ECU assembly)
ABS Control Prevents the wheels from locking during sudden stops.	Brake actuator assembly	-	ABS control is continued.	-	-
Brake Assist Control Estimates the driver's intentions based on the speed and force that the brake pedal is depressed and assists the braking force.	Brake actuator assembly	Airbag sensor assembly	Brake assist control is stopped.	ABS warning light illuminates. Slip indicator light illuminates.	U012587 (Brake actuator assembly)
TRC/VSC/VDIM Control Suppresses vehicle instability, such as sliding sideways when cornering and wheel slippage when starting off.	Brake actuator assembly	ECM Airbag sensor assembly Steering sensor	TRC/VSC/VDIM control is stopped.	ABS warning light illuminates. Slip indicator light illuminates.	U010087 U012587 U012687 U115C87 (Brake actuator assembly)
Hill start assist control Maintains the brake oil pressure for 2 seconds when the brake pedal is released when starting off the vehicle from a stop on a slope.	Brake actuator assembly	ECM Airbag sensor assembly Steering sensor	Hill start assist control is stopped.	ABS warning light illuminates. Slip indicator light illuminates.	U010087 U012587 U012687 U115C87 (Brake actuator assembly)
Brake Hold Control Maintains the brake oil pressure when the vehicle is stopped.	Brake actuator assembly	ECM Airbag sensor assembly Steering sensor	Brake hold control is stopped.	ABS warning light illuminates. Slip indicator light illuminates.	U010087 U012587 U012687 U115C87 (Brake actuator assembly)
SCB Applies control to avoid a secondary collision after collision is detected.	Brake actuator assembly	ECM Airbag sensor assembly	Control is continued.	ABS warning light illuminates. Slip indicator light illuminates.	U010087 U012587 U015187 U115C87 (Brake actuator assembly)
Meter Displays advice or warning.	Combination meter assembly	ECM Brake Actuator Assembly Power Steering ECU Assembly Main body ECU (multiplex network body ECU) Air conditioning amplifier assembly Certification ECU (smart key ECU assembly) Airbag sensor assembly Engine stop and start ECU Forward recognition camera Steering sensor	Vehicle information is not displayed.	Abnormal light operation.	U010087 U012687 U012987 U013187 U014087 U015187 U016487 U016887 U023587 U023A87 U110387 (Combination meter assembly)
Speedometer Displays the current vehicle speed on the meter mirror sub-assembly using the current vehicle speed signal sent from the combination meter assembly.	Meter mirror sub-assembly	Combination meter assembly	Vehicle speed displayed value: Displays 0. Vehicle speed unit: Does not display.	-	U015587 (Meter mirror sub-assembly)
Brightness Adjustment Adjusts the meter mirror sub-assembly display brightness by customization through the multi-information display.	Meter mirror sub-assembly	Combination meter assembly	Control is performed as though there are no brightness up/down inputs (= the last brightness condition is maintained). The last headlight illumination condition is maintained.	-	U015587 (Meter mirror sub-assembly)
Display Position Adjustment Adjusts the meter mirror sub-assembly display position by customization through the multi-information display.	Meter mirror sub-assembly	Combination meter assembly	Control is performed as though there are no position up/down inputs (The last position condition is maintained).	-	U015587 (Meter mirror sub-assembly)
Switching Adjustment Adjusts switching of the meter mirror sub-assembly display in the customization through the multi-information display.	Meter mirror sub-assembly	Combination meter assembly	Control is performed as though there are no display switching inputs (= the display is not switched).	-	U015587 (Meter mirror sub-assembly)
Tachometer Displays the current engine speed on the meter mirror sub-assembly using the engine speed signal sent from the engine.	Meter mirror sub-assembly	ECM	Engine speed: Displays 0 rpm.	-	U010087 (Meter mirror sub-assembly)
Tachometer (Variable Red Zone) Variably displays the red zone using the red zone engine speed signal sent from the engine.)	Meter mirror sub-assembly	ECM	Red zone engine speed: Displays 3700 rpm.	-	U010087 (Meter mirror sub-assembly)
Eco Driving Indicator Displays the eco driving indicator on the meter mirror sub-assembly using the eco zone display condition amount signal sent from the engine.)	Meter mirror sub-assembly	ECM	Performs control as though Eco zone display condition amount inputs are in the initial condition.	-	U010087 (Meter mirror sub-assembly)
Road Sign Assist Display Displays traffic signs (such as speed limit signs) using the traffic sign signal sent from the forward recognition camera or object recognition camera.	Meter mirror sub-assembly	Forward recognition camera	Traffic signs: Do not display.	-	U023A87 (Meter mirror sub-assembly)
Ambient Temperature/Road Surface Ice Display (Displays the road surface ice display mark and ambient temperature on the meter mirror sub-assembly using the ambient temperature signal sent from the air conditioning amplifier assembly.	Meter mirror sub-assembly	Air conditioning amplifier assembly	Ambient temperature: Displays error.	-	U016487 (Meter mirror sub-assembly)
Pre-collision System Display Displays "BRAKE!" on the meter mirror sub-assembly using the Pre-collision System warning display signal sent from the millimeter wave radar sensor assembly.	Meter mirror sub-assembly	Forward recognition camera	Pre-collision System warning: Does not display.	-	U110487 (Meter mirror sub-assembly)
Dynamic Radar Cruise Control System Display Displays the radar cruise control preceding vehicle, set vehicle distance and set vehicle speed on the meter mirror sub-assembly using the radar cruise control display signal sent from the engine.	Meter mirror sub-assembly	ECM	Radar cruise control display (preceding vehicle, merging vehicle, inter-vehicle time): Does not display.	-	U010087 (Meter mirror sub-assembly)
LDA/LKA Displays the left and right white line marks, steering mark and rest encouragement mark on the meter mirror sub-assembly using the LDA display signal sent from the forward recognition camera.	Meter mirror sub-assembly	Forward recognition camera	LDA display (white lines, steering mark and rest encouragement mark): Does not display.	-	U023A87 (Meter mirror sub-assembly)
Master Caution Displays the master caution icon and messages on the meter mirror sub-assembly using the master caution display signal sent from the combination meter assembly.	Meter mirror sub-assembly	Combination meter assembly	Does not display.	-	U015587 (Meter mirror sub-assembly)
Information Does not display the information icon and messages on the meter mirror sub-assembly using the information display signal sent from the combination meter assembly.	Meter mirror sub-assembly	Combination meter assembly	Does not display.	-	U015587 (Meter mirror sub-assembly)
Display Customization Does not display the information icon and messages on the meter mirror sub-assembly using the information display signal sent from the combination meter assembly.	Meter mirror sub-assembly	Combination meter assembly	Control is performed as though the customize switch is off.	-	U015587 (Meter mirror sub-assembly)
Pedestrian Warning Alert Displays the pedestrian warning alert using the target direction signal sent from the forward recognition camera.	Meter mirror sub-assembly	Forward recognition camera	Pedestrian warning alert: Does not display.	-	U110487 (Meter mirror sub-assembly)
FCTA Displays the FCTA using the CTA detection signals sent from the forward recognition camera.	Meter mirror sub-assembly	Forward recognition camera	FCTA: Does not display.	-	U110487 (Meter mirror sub-assembly)
Lane Trace Control System Displays the advanced driving support display matched with the shape of the actual curve (LDA white lines, LTC self-confident wall, ACC preceding vehicle, set vehicle distance. etc.) using the curve number signals sent from the forward recognition camera.	Meter mirror sub-assembly	Forward recognition camera	Does not display.	-	U110487 (Meter mirror sub-assembly)
LCS Displays the LCS operation condition on the meter mirror sub-assembly using the LCS planned lane signals sent from the forward recognition camera.	Meter mirror sub-assembly	Forward recognition camera	Does not display.	-	U110487 (Meter mirror sub-assembly)
Stop Support System Displays the stop support system operation condition on the meter mirror sub-assembly using the stop support system display request signals sent from the forward recognition camera.	Meter mirror sub-assembly	Forward recognition camera	Does not display.	-	U110487 (Meter mirror sub-assembly)
Speed Management Displays the speed management icon on the meter mirror sub-assembly using the speed management display request signals sent from the engine.	Meter mirror sub-assembly	ECM	Does not display.	-	U010087 (Meter mirror sub-assembly)
Brake Override System Displays the Brake Override System operation condition on the meter mirror sub-assembly using the Brake Override System display signal sent from the engine.	Meter mirror sub-assembly	ECM	Does not display.	-	U010087 (Meter mirror sub-assembly)
Drive Start Control Displays the Drive Start Control operation condition on the meter mirror sub-assembly using the Drive Start Control display signal sent from the engine.	Meter mirror sub-assembly	ECM	Does not display.	-	U010087 (Meter mirror sub-assembly)
Road Sign Assist System - Dynamic Radar Cruise Control System Displays a box around the target sign on the meter mirror sub-assembly and an arrow next to the set vehicle speed using the Road Sign Assist System - Dynamic Radar Cruise Control System display signals sent from the engine.	Meter mirror sub-assembly	ECM	Road Sign Assist System - Dynamic Radar Cruise Control System target sign box: Does not display. Road Sign Assist System - Dynamic Radar Cruise Control System arrow: Does not display.	-	U010087 (Meter mirror sub-assembly)
Language-linked (Combination meter assembly) Switches the language displayed on the meter mirror sub-assembly (combination meter assembly text) to match the language set by the combination meter assembly.	Meter mirror sub-assembly	Combination meter assembly	Control is performed using the last signal received.	-	U115587 (Meter mirror sub-assembly)
Destination Switching Switches the tachometer units and ambient temperature units according to the destination.	Meter mirror sub-assembly	Main body ECU (multiplex network body ECU)	Control is performed using the last signal received.	-	U014287 (Meter mirror sub-assembly)
Air Conditioning Control Corrects the engine speed by performing idle up, etc. Adjusts the air temperature, airflow mode and airflow volume according to the engine coolant temperature. Performs the engine coolant temperature map calibration and switches compressor lock judgment value based on engine type.	ECM	Air conditioning amplifier assembly	While the ignition switch is ON, control is performed using the default engine coolant temperature value 80°C (176°F). While the ignition switch is ON, control is performed using the default value for the engine type. There is no default behavior for power source modes other than ON.	MIL illuminates.	U010087 (Air conditioning amplifier assembly)
Compressor Control Determines whether the compressor is locked according to NE.	ECM	Air conditioning amplifier assembly	While the ignition switch is ON, control is performed using the default NE value (0 rpm). There is no default behavior for power source modes other than ON.	MIL illuminates.	U010087 (Air conditioning amplifier assembly)
Simple Load Control Limits electrical load control according to the load control level.	Power steering ECU assembly	Air conditioning amplifier assembly	While the ignition switch is ON, the current state is maintained (during a reset, there is no load control). There is no default behavior for power source modes other than ON.	-	U013187 (Air conditioning amplifier assembly)
Destination Determination Control Switches air conditioning system control pattern according to destination information.	Main body ECU (multiplex network body ECU)	Air conditioning amplifier assembly	While the ignition switch is ON, the previous state is maintained (during a reset, dimming control is performed). There is no default behavior for power source modes other than ON.	-	U014087 (Air conditioning amplifier assembly)
Remote Start Control Controls the air conditioning system operation state according to remote start information.	Main body ECU (multiplex network body ECU) (Option connector (bus buffer ECU))	Air conditioning amplifier assembly	While the ignition switch is ON, remote start control is not performed. There is no default behavior for power source modes other than ON.	-	-
Ambient Temperature Adjustment Control Switches the air conditioning system operation condition and adjusts the ambient temperature display output value according to the vehicle speed information.	Combination meter assembly	Air conditioning amplifier assembly	While the ignition switch is ON, control is performed using the default vehicle speed. There is no default behavior for power source modes other than ON.	-	U015587 (Air conditioning amplifier assembly)
Stop and Start System Stops the engine when the vehicle is stopped.	Engine stop and start ECU	Air conditioning amplifier assembly Brake actuator assembly ECM Steering sensor Airbag sensor assembly Main body ECU (multiplex network body ECU) Power steering ECU assembly Combination meter assembly	During Eco-run: It is restarted. Not during Eco-run: Eco-run is prohibited.	Stop and start cancel indicator light blinks.	U010087 U012687 U012987 U013187 U014087 U015187 U016487 (Engine stop and start ECU)

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