TROUBLESHOOTING <Vehicles with discharge headlamp>

DISCHARGE HEADLAMP TROUBLESHOOTING STRATEGY

WARNING

Do not touch the socket and the connector while the headlamps are on. High voltage current is flowing in the socket and the connector while the headlamps are on. If you fail to handle them correctly, a serious injury or damage may be caused.

WARNING

Do not attempt to use a tester to check them. If a tester is used, a serious injury or damage may be caused by high-voltage current.

WARNING

Do not turn on the headlamps while the controller or the bulb is removed. If the headlamps are turned on while the controller or the bulb is removed, serious injury or damage may be caused.

WARNING

Before service work, ensure that the battery terminal and the controller connector is disconnected. Do not touch the components with wet hands. If you work on the components with wet hands or in wet conditions, serious injury may be caused.

CAUTION

Do not illuminate the bare headlamp bulb. If the headlamp bulb illuminates without fitting it in the headlamp unit, it may burst due to rise in its internal pressure.

CAUTION

If the discharge headlamp is damaged, strictly observe "How to check discharge headlamp components." If you fail to observe "How to check discharge headlamp components," the vehicle may be damaged.

How to check discharge headlamp components.

Visual check of the controller (case)

If any of the defects below are found, replace the controller.

Items to be checked	Why the controller should be replaced
Obvious deformation (warping, twisting, dents, nicks, cracks, chipped edges) of the controller case	Because the printed circuit board or the element(s) may be cracked
Damaged connector (chipped or cracked plastics, or deformed terminal)	Because the damaged part(s) may cause poor connection

Check the wiring harness between the controller and the bulb.

If any of the defects below are found, replace the wiring harness between the controller and the bulb.

CAUTION

If the wiring harness between the controller and the bulb is defective, always replace it. Attempting to repair the wiring harness may cause a melted harness wire.

Items to be checked	Why the controller should be replaced
Wiring harness shield damaged (breakage)	Causing abnormal noise
Damaged connector (chipped or cracked plastics, or deformed terminal)	Because the damaged part(s) may cause poor connection

Checking while the headlamps are on

If any of the defects below are found, replace the controller.

CAUTION

While the headlamps are on, do not touch the headlamp bulbs. There is a high risk of scalding, as the headlamp bulb will become extremely hot.

NOTE: Ensure that the headlamp control system and its circuit (power supply control at engine start and during steady illumination, high-voltage generating circuit, etc.) are working normally. Then check whether internal breakage has occurred in the controller. However, some internal breakage may not be able to be found.

Check how the lamps illuminate.
Turn on and off the headlamps several times when they are cold and warm. Observe how the headlamps illuminate.
Observe the headlamps until they illuminate steadily (approximately five minutes after switching on them). Check that the headlamps do not flash or flicker.
Turn on the headlamps for thirty minutes. Check that the brightness is the same between right and left lamps.
Turn on the headlamps for thirty minutes. Check that the headlamps do not flash or flicker.

How to diagnose the discharge headlamps

Check that the connectors are connected securely and the fuse has not been blown.

Before starting the diagnosis, read through the "Symptom chart" to understand what and how you should do. Follow all the procedures carefully.

The components should be checked with their connectors disconnected.

Symptom chart

Item to be checked	Symptom
Item to be checked	The headlamps do not illuminate.	The headlamps flicker.	The headlamps are dim.
Fuse	1	-	-
Wiring harness and connector	2	1	-
Column switch	3	-	-
Bulb	4	2	1
Controller	5	3	2

NOTE:

The numbers indicate the sequence in which the component is checked.

Refer to GROUP 54C or 54D for the troubleshooting other than above.

For using SWS monitor: GROUP 54C, SWS Troubleshooting .

For not using SWS monitor: GROUP 54D, SWS Troubleshooting .

If the ETACS-ECU failed, only the low-beam headlamps will illuminate as a fail-safe measure.