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 the pages for each system.)
| Function | Control Master | System Related | Fail-safe Operation | Driver Detectable | DTC Detection (ECU that stored DTC) |
|---|---|---|---|---|---|
| Air Conditioning Control
|
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
|
Air conditioning amplifier assembly | ECM | Control is performed based on default engine speed of 0 rpm. | - | U0100 (Air conditioning amplifier assembly) |
| Simple Load Control
|
Air conditioning amplifier assembly | Power steering ECU assembly | Load control is not performed. | - | U0131 (Air conditioning amplifier assembly) |
| Panel Dimming Control
|
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
|
Air conditioning amplifier assembly | Main body ECU (multiplex network body ECU) | Maintains the latest state. | - | U0142 (Air conditioning amplifier assembly) |
| Insolation Correction Control
|
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
|
Air conditioning amplifier assembly | Combination meter assembly | Control is performed based on default vehicle speed of 0 km/h (0 mph). |
|
U0155 (Air conditioning amplifier assembly) |
| Air Conditioning Eco Mode Control
|
Air conditioning amplifier assembly | ECM | Maintains the latest state (Maintained in normal condition after reset). | - | U0100 (Air conditioning amplifier assembly) |
| Door Lock
|
Main body ECU (multiplex network body ECU) |
|
|
- | U0100 U0101 U0151 U0155 (Main body ECU (multiplex network body ECU)) |
| Display Automatic Dimming
|
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
|
Main body ECU (multiplex network body ECU) |
|
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) |
|
|
- | U0101 U0327 (Main body ECU (multiplex network body ECU)) |
| Seat and Mirror Control | Main body ECU (multiplex network body ECU) |
|
|
- | 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
|
ECM | Combination meter assembly |
|
- | - |
| Electric Load Control
|
ECM |
|
Idle up according to electric load is not performed. | - | - |
| Air Conditioning Cooperative Operation
|
ECM | Air conditioning amplifier assembly | Air conditioning system does not use cooperative controls. (Idle up is not performed.) | - | - |
| Charge Control
|
ECM | Air conditioning amplifier assembly | Idle up according to charging request is not performed. | Taillights flicker and blower airflow changes. | - |
| Eco Control
|
ECM | Combination meter assembly | Eco mode does not operate. | - | - |
| ECT System Indicator Display
|
ECM | Combination meter assembly | Indicator light does not illuminate. | - | - |
| Neutral Control
|
ECM |
|
Neutral control is not performed. | - | - |
| Coast Downshift Timing Change According to Air Conditioning Load
|
ECM | Air conditioning amplifier assembly |
|
- | - |
| Cruise Control
|
ECM |
|
Cruise control does not operate. | Displays messages on the multi-information display. | - |
| Stop and Start Control
|
ECM | Engine stop and start ECU | Stop and start control does not operate. | Displays messages on the multi-information display. | U110387 (ECM) |
| Stop and Start System
|
Engine stop and start ECU |
|
|
Displays messages on the multi-information display. | U0100 U0104 U0121 U0123 U0126 U0131 U0132 U0140 U0151 U0164 (Engine stop and start ECU) |
| Power Steering Control
|
Power steering ECU assembly |
|
Assist force restricted. | EPS warning light illuminates. | U0100 U0129 (Power steering ECU assembly) |
| VDIMα System
|
|
Skid control ECU (brake actuator assembly) | VDIMα control is stopped. | EPS warning light illuminates. | - |
| VDIMβ System
|
|
|
VDIMβ control is stopped. |
|
U0129 U0130 (Power steering ECU assembly) |
| Entry Function
|
|
|
Entry unlock is performed again. |
|
U0100 U0142 U0155 U1103 (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
|
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
|
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 |
|
U0129 (Combination meter assembly) |
| Tachometer Display | Combination meter assembly | ECM | None |
|
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
|
Combination meter assembly |
|
Lights do not illuminate or lights remain illuminated. | Abnormal light operation | U0100 U0129 U0130 U0131 U0142 U0151 U0182 U023A U1104 (Combination meter assembly) |
| Linking-up with Multi-information Display
|
Combination meter assembly | Radio receiver assembly | None | - | U0163 (Combination meter assembly) |
| Pedestrian Protection Function (Pop-up Hood)
|
Airbag sensor assembly |
|
Airbag sensor assembly prohibits pedestrian protection function and performs calculations accordingly. | - | U0125 U0126 U0129 U0130 (Airbag sensor assembly) |
| ABS Control | Skid control ECU (brake actuator assembly) | Yaw rate sensor | When control is being performed:
When control is not being performed:
|
|
U0073 U0124 (Skid control ECU (brake actuator assembly)) |
| VSC/TRC/VDIM Control | Skid control ECU (brake actuator assembly) |
|
When control is being performed:
When control is not being performed:
|
|
U0073 U0100 U0124 U0126 U0130 (Skid control ECU (brake actuator assembly)) |
| Hill-start Assist Control
|
Skid control ECU (brake actuator assembly) |
|
Control cannot be performed. |
|
U0073 U0100 U0124 U0126 (Skid control ECU (brake actuator assembly)) |
| Headlight Leveling Control (Headlight Control)
|
No. 1 headlight ECU sub-assembly LH |
|
Control cannot be performed. | Displays messages on the multi-information display. | U0129 U0142 (No. 1 headlight ECU sub-assembly LH) |
| Low Beam, High Beam
|
Main body ECU (multiplex network body ECU) | No. 1 headlight ECU sub-assembly LH | Forces the low beams to illuminate. | - | U0142 (No. 1 headlight ECU sub-assembly LH) |
| VGRS Control
|
Front steering control ECU |
|
VGRS control is stopped. | Displays messages on the multi-information display. | U0100 U0101 U0125 U0126 U0129 U0131 (Front steering control ECU) |
| AVS Control
|
Absorber control ECU |
|
|
- | U0100 U0101 U0122 U0124 U0126 U0130 U1103 (Absorber control ECU) |
| Air Conditioning Control
|
Radio receiver assembly | Air conditioning amplifier assembly |
|
Displays messages on the multi-display. | U0073 U0164 (Radio receiver assembly) |
| LEXUS Parking Assist-sensor System Setting/Notification
|
Radio receiver assembly |
|
|
Clearance sonar icon is not displayed. | U0073 U0100 U1110 (Radio receiver assembly) |
| Fuel Consumption Display
|
Radio receiver assembly |
|
When communication with ECM or skid control ECU is interrupted:
When communication with combination meter is interrupted:
|
- | U0100 U0129 U0155 (Radio receiver assembly) |
| Destination Identification
|
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) |
| Tire Pressure Monitoring System
|
Radio receiver assembly | Main body ECU (multiplex network body ECU) |
|
- | U0073 (Radio receiver assembly) |
| Power Tilt and Power Telescopic Steering Column Control
|
Multiplex tilt and telescopic ECU |
|
|
- | U0142 U0208 (Multiplex tilt and telescopic ECU) |
| Seat Position Memory System
|
|
|
Controls the seat position based on operation conditions. | - | - |
| Illumination Control
|
|
Main body ECU (multiplex network body ECU) | Mirror foot illumination is turned off. | - | U0142 (Outer mirror control ECU assembly (for driver side)) (Outer mirror control ECU assembly (for front passenger side)) |
| Mirror Surface Adjustment |
|
Main body ECU (multiplex network body ECU) | Mirror surface position cannot be memorized or recalled. | - | U0142 (Outer mirror control ECU assembly (for driver side)) (Outer mirror control ECU assembly (for front passenger side)) |
| Mirror Heaters |
|
|
Mirror heaters do not operate. | - | U0142 (Outer mirror control ECU assembly (for driver side)) (Outer mirror control ECU assembly (for front passenger side)) |
| Mirror Retract/Return Operation
|
|
Main body ECU (multiplex network body ECU) | Mirrors cannot be retracted or returned. | - | - |
| Reverse-shift Linked Door Mirror Operation |
|
Main body ECU (multiplex network body ECU) | Reverse-shift linked door mirror function does not operate. | - | U0142 (Outer mirror control ECU assembly (for driver side)) (Outer mirror control ECU assembly (for front passenger side)) |
| Mirror Surface Position Memory and Recall |
|
Main body ECU (multiplex network body ECU) | Mirror surface position cannot be memorized or recalled. | - | U0142 (Outer mirror control ECU assembly (for driver side)) (Outer mirror control ECU assembly (for front passenger side)) |
| Seat Memory Switch Signal Forwarding
|
Main body ECU (multiplex network body ECU) |
|
Seat position memory settings cannot be memorized or recalled. | - | - |
| Dynamic Radar Cruise Control System
|
Driving support ECU assembly |
|
Control stops. | Displays messages on the multi-information display. | U0100 U0125 U0126 U0129 U0235 U1104 (Driving support ECU assembly) |
| Pre-collision System
|
Driving support ECU assembly |
|
Control stops. |
|
U0100 U0125 U0126 U0129 U0235 U023A U1002 U1104 (Driving support ECU assembly) |
| LEXUS Parking Assist-sensor System Control
|
Clearance warning ECU assembly | Combination meter assembly | Clearance sonar detection will be operated based on a vehicle speed of 20 km/h (12 mph) or more. | - | U0155 (Clearance warning ECU assembly) |
| Shift position judgment
|
Clearance warning ECU assembly | ECM | Control operates with the default shift position (P). | - | U0101 (Clearance warning ECU assembly) |
| Voice Warning Availability Confirmation
|
Clearance warning ECU assembly | Main body ECU (multiplex network body ECU) | Assumes that there is no voice warning. | - | - |
| LKA/LDA/SWS System (Recognizes the lane markers of the lane the vehicle is in using the forward recognition camera and performs the following operations based on the vehicle condition and information captured by the forward recognition camera.)
|
Forward recognition camera |
|
Lane departure alert system control stops. |
|
U0100 U0101 U0123 U0126 U0129 U0130 U0131 U0142 U0155 U0235 U023A U1104 (Forward recognition camera) |
| Automatic High Beam System
|
Forward recognition camera |
|
Maintains the same condition. | Automatic high beam indicator light blinks. | U0100 U0101 U0123 U0129 U0235 (Forward recognition camera) |
| Road Sign Assist Function
|
Forward recognition camera |
|
Road sign assist function is canceled. | Displays messages on the multi-information display. | U0100 U0101 U0123 U0129 U0142 U0155 (Forward recognition camera) |
| Blind Spot Monitor Control
|
Blind spot monitor sensor LH |
|
None | Displays messages on the multi-information display. | U0100 U0125 U0126 U0129 U0142 (Blind spot monitor sensor LH) |
| Parking Assist Monitor without Parallel Parking Assist Function
|
Rear television camera assembly |
|
Parking assist monitor function is prohibited. |
|
U0100 U0126 U0129 U0130 U0131 U0140 U0163 U0233 U1110 (Rear television camera assembly) |
| ERA-GLONASS
|
Telematics transceiver | ECM | When communication with the ECM is lost or there is a communication error, the manual (SOS) switch indicator (red) illuminates. | - | U0100 (Telematics transceiver) |
| ASC System
|
Stereo component equalizer assembly |
|
Simulated engine sound output is stopped. | - | U0100 U0122 U0142 (Stereo component equalizer assembly) |