Fail-Safe Chart [10/2016 - 09/2020]
WARNING: This page does not describe the selected car, but rather 9 other vehicles, including the 2020 Lexus IS 350, 2020 Lexus IS 300, 2019 Lexus IS 350, 2019 Lexus IS 300, and 2018 Lexus IS 350. However, it is still accessible from the selected car via links, so may be relevant.
- FAIL-SAFE FUNCTION
If the headlight swivel ECU assembly detects a malfunction in the AFS (adaptive front-lighting system), it will take the actions indicated in the table below.
Item Abnormality Detection Condition Return Leveling Fail-safe Control Swivel Fail-safe Control Return Condition Warning Indicator Multi-information Display Headlight swivel motor (swivel function) Communication stop Lowers the headlight swivel motor 1.0° and continues control. Returns both headlights to the front position. Signals are received normally. Flashes Message displayed - Open circuit
- Short circuit
- Overheat
- Gear malfunction
- Returns the normal headlight swivel motor to the front position.
- Stops the abnormal headlight swivel motor at the current position.
Engine switch is turned on (IG) again. Flashes Message displayed Abnormal voltage Normal value is detected. Does not illuminate Message not displayed Headlight swivel motor (leveling function) Communication stop - If the position is higher than the initial position, the headlight swivel motor is returned to the initial position.
- If the position is lower than the initial position, the headlight swivel motor is stopped at the current position.
Returns both headlight swivel motors to the initial position. Signals are received normally. Flashes Message displayed - Open circuit
- Short circuit
- Overheat
- Stops the abnormal headlight swivel motor at the current position.
- If the position of the normal motor is higher than the initial position, it is returned to the initial position. If the position of the normal motor is lower than the initial position, it is stopped at the current position.
Engine switch is turned on (IG) again. Abnormal voltage Normal value is detected. Does not illuminate Message not displayed Steering sensor Abnormal steering sensor None. Returns both headlights to the front position. Engine switch is turned on (IG) again. Flashes Message displayed Wheel speed Abnormal wheel speed sensor - If either of the wheel speed signals is abnormal, control continues using the normal signal.
- If both of the wheel speed signals are abnormal, judgment is performed as though the vehicle is stationary and control continues.
Continues control using the same speed as before the sensor malfunction detection, the headlight swivel motors are returned to the initial position. When the sensor(s) return to normal. Flashes Message displayed Rear height control sensor sub-assembly LH Abnormal vehicle angle (front to rear inclination) - If the headlight swivel motor position is higher than the initial position, the headlight swivel motors are returned to the initial position.
- If the headlight swivel motor position is lower than the initial position, the headlight swivel motors are stopped at the current position.
Returns both headlight swivel motors to the initial position. Normal value is detected. Flashes Message displayed Power source malfunction Engine switch is turned on (IG) again. Abnormal rear height control sensor sub-assembly LH signal Normal value is detected. CAN communication Main body ECU (multiplex network body ECU) communication error (headlight signal) None. Returns both headlight swivel motors to the initial position. Signals are received normally. Flashes Message displayed Main body ECU (multiplex network body ECU) communication error (destination information) None. Main body ECU (multiplex network body ECU) communication error (VAST request) Main body ECU (multiplex network body ECU) communication error (time stamp) Does not illuminate Message not displayed ECM communication error (power source mode on IG signal) Flashes Message displayed ECT ECU communication error (gear signal) Returns both headlight swivel motors to the initial position. Steering sensor communication error (steering angle signal) Brake actuator assembly (skid control ECU) communication error (vehicle speed signal) Control is performed as though the vehicle is stationary. Combination meter assembly communication error (AFS On/Off switch signal) None. None. Does not illuminate Message not displayed Headlight swivel ECU assembly Abnormal headlight swivel ECU assembly None. None. Engine switch is turned on (IG) again. Flashes Message displayed Initialization of rear height control sensor sub-assembly LH Initialization of rear height control sensor sub-assembly LH not completed Adjusts the headlight swivel motor position to a step value so that the height will be as same as that of an unloaded vehicle. Returns both headlight swivel motors to the initial position. Initialization is completed Flashes (6 times) Message displayed Abnormal rear height control sensor sub-assembly LH data at initialization Flashes Message displayed Synchronization of vehicle information Vehicle specifications have not been stored Adjusts the headlight swivel motor position to a step value so that the height will be as same as that of an unloaded vehicle. Returns both headlight swivel motors to the initial position. Synchronization is completed Flashes (0.5 Hz) Message displayed Headlight swivel ECU assembly for another vehicle specification is installed - If the position is higher than the initial position, the headlight swivel motor is returned to the initial position.
- If the position is lower than the initial position, the headlight swivel motor is stopped at the current position.
Headlight swivel ECU assembly for current vehicle specification is installed Flashes Message displayed