Toyota Venza: Fail-safe Chart

Toyota Venza Service Manual / Lighting (ext) / Lighting System / Fail-safe Chart

FAIL-SAFE CHART

1. HID Headlight System

(a) Light Control ECU

(1) The light control ECU stops illuminating the HID headlights when any of the following abnormalities are detected.

Condition	Content
Open in output side circuit	Stops illuminating the headlights. Keeps the headlights off until the power is reinstated (by turning the light control switch from off to the head position).
Short between output terminals	Stops illuminating the headlights. Keeps the headlights off until the power is reinstated (by turning the light control switch from off to the head position).
Leak between output terminal and ground point	Stops illuminating the headlights. Keeps the headlights off until the power is reinstated (by turning the light control switch from off to the head position).
Excessively low output voltage	Stops illuminating the headlights when the output voltage becomes too low (31 +/- 3 V or less). Keeps the headlights off until the power is reinstated (by turning the light control switch from off to the head position).
Excessively high output voltage	Stops illuminating the headlights when the output voltage becomes too high (69 +/- 4 V or more). Keeps the headlights off until the power is reinstated (by turning the light control switch from off to the head position).
Excessively high input voltage	Stops illuminating the headlights when the input voltage becomes too high (20 +/- 3 V or more). Illuminates the headlights again when the voltage returns to the operating voltage range (10 to 16 V).
Low input voltage	Stops illuminating the headlights when the input voltage becomes too low (below 6 V). Illuminates the headlights again when the voltage returns to the operating voltage range (10 to 16 V).

2. Automatic Headlight Beam Level Control System

(a) The headlight leveling ECU assembly operates in fail-safe mode if an abnormal condition such as those listed below has been detected, and keep the last high beam status.

Item	Abnormality Detection Condition	Return Condition	Warning Indicator
Height control sensor power source voltage	Abnormal height control sensor power source voltage (4.6 V or less, or 6.25 or more) is detected.	Abnormal voltage is not detected for 5 seconds consecutively	Illuminated
Height control sensor signal voltage	Abnormal height control sensor signal voltage (0.25 V or less, or 4.75 V or more) is detected.		Illuminated
High power source voltage	Abnormal high ignition voltage (18.5 V or more) is detected.	Voltage of 17.5 V or less is detected	Not illuminated
Low power source voltage	Abnormal low ignition voltage (9.0 V or less) is detected.	Voltage of 9.3 V or more is detected for 0.1 seconds consecutively	Not illuminated
Reset while running	Reset by a temporary blackout etc. while running.	Vehicle is stopped	Not illuminated

3. Automatic Light Control System

If the main body ECU (driver side junction block assembly) detects a malfunction in the automatic light control sensor, the main body ECU (driver side junction block assembly) effects fail-safe control to prohibit the automatic light control. If the low beam headlights and taillights are on, the lights will remain on until the light control switch is turned off.

4. Automatic High Beam System

(a) The main body ECU (driver side junction block assembly) operates in the fail-safe mode if an abnormal condition such as those listed below has been detected.

Item	Abnormality Detection Condition	Return Condition	Warning indicator
Steering Angle Sensor Signal Malfunction	Steering angle sensor Malfunction is detected.	Steering angle sensor malfunction is not detected, and ignition switch is turned to ON again.	Flash
	Steering angle sensor zero point memory invalid is detected.	Steering angle sensor zero point memory valid is detected.	Not illuminated
	Steering angle sensor data continuity invalid is detected.	Steering angle sensor data continuity invalid flag is detected.	Not illuminated
Speed Sensor Signal Malfunction	Abnormal speed sensor signal is detected.	Normal speed sensor signal is detected.	Flash
CAN Communication Signal Malfunction	Normal CAN communication signal is not detected for more than 10 seconds consecutively.	Normal CAN communication signal is detected.	Flash
Automatic High Beam Sensor	Communication stopped for 10 seconds consecutively.	Normal communication signal is detected.	Flash

Dtc Check / Clear

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FREEZE FRAME DATA 1. FREEZE FRAME DATA (a) Whenever a DTC is detected, the AFS ECU (headlight swivel ECU assembly) stores the current vehicle (sensor) state as Freeze Frame Data. 2. CHECK FREEZE ...

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