Headlamp (LO) Circuit

HEADLAMP (LO) CIRCUIT





Description
The IPDM E/R (intelligent power distribution module engine room) controls the headlamp low relay based on inputs from the BCM via the CAN communication lines. When the headlamp low relay is energized, power flows through fuses 40 and 41, located in the IPDM E/R. Power then flows to the front combination lamps to the headlamp low beam.




Component Function Check
1.CHECK HEADLAMP (LO) OPERATION
WITHOUT CONSULT-III
1. Start IPDM E/R auto active test. Diagnosis Description.
2. Check that the headlamp is turned ON.

NOTE:
HI/LO is repeated 1 second each when using the IPDM E/R auto active test.
CONSULT-III
1. Select "EXTERNAL LAMPS" of IPDM E/R active test item.
2. With the test items operating, check that the headlamp is turned ON.





Is the headlamp turned ON?
YES - Headlamp (LO) is normal.
NO - SEE Diagnosis Procedure.




Diagnosis Procedure
Regarding Wiring Diagram information, [1][2]Electrical Diagrams (without DTRL) or [1][2]Daytime Running Lamp (with DTRL).
1.CHECK HEADLAMP (LO) FUSES
1. Turn the ignition switch OFF.
2. Check that the following fuses are not open.





Is the fuse open?
YES - Replace the fuse after repairing the affected circuit.
NO - GO TO 2
2.CHECK HEADLAMP (LO) OUTPUT VOLTAGE





1. Turn the ignition switch OFF.
2. Disconnect the front combination lamp connector.
3. Turn the ignition switch ON.
4. Turn the low beam headlamps ON.
5. With the low beam headlamps ON, check the voltage between the combination lamp connector and ground.






Is battery voltage present?
YES - GO TO 8
NO (Except LH with DTRL)-CHECK HEADLAMP (LO) CIRCUIT FOR OPEN GO TO 3
NO (LH with DTRL)-CHECK HEADLAMP (LO) CIRCUIT FOR OPEN GO TO 4
3.CHECK HEADLAMP (LO) CIRCUIT FOR OPEN (EXCEPT LH WITH DTRL)





1. Turn the ignition switch OFF.
2. Disconnect IPDM E/R connector E123.
3. Check continuity between the IPDM E/R harness connector (A) and the front headlamp harness connector (B).





Does continuity exist?
YES - Replace IPDM E/R. Service and Repair.
NO - Repair the harnesses or connectors.
4.CHECK HEADLAMP (LO) CIRCUIT FOR OPEN (LH WITH DTRL)
1. Turn the ignition switch OFF.
2. Disconnect IPDM E/R connector E123 and daytime light relay 2 connector.
3. Check continuity between the IPDM E/R harness connector and the daytime light relay 2 harness connector.





Does continuity exist?
YES - GO TO 5
NO - Repair the harnesses or connectors.
5.CHECK DAYTIME LIGHT RELAY 2 CIRCUIT
1. Check continuity between the daytime light relay 2 harness connector and the front headlamp LH harness connector.





2. Check continuity between the daytime light relay 2 harness connector and ground.





Is the measurement value normal?
YES - GO TO 6
NO - Repair the harnesses or connectors.
6.CHECK DAYTIME LIGHT RELAY 2 GROUND CIRCUIT
Check continuity between daytime light relay 2 harness connector and ground.





Does continuity exist?
YES - GO TO 7
NO - Repair the harness or connector.
7.CHECK DAYTIME LIGHT RELAY 2
Check daytime light relay 2. SEE Component Inspection.
Is the inspection result normal?
YES - Replace IPDM E/R. Service and Repair.
NO - Replace daytime light relay 2.
8.CHECK FRONT HEADLAMP (LO) GROUND CIRCUIT





Check continuity between the front headlamp harness connector terminal 2 and ground.





Does continuity exist?
YES - Inspect the headlamp bulb.
NO (Except LH with DTRL)- Repair the harness.
NO (LH with DTRL)- GO TO 9
9.CHECK CONTINUITY BETWEEN FRONT HEADLAMP LH (HI) AND DAYTIME LIGHT RELAY 1
1. Disconnect daytime light relay 1 connector.
2. Check continuity between front headlamp LH harness connector and daytime light relay 1 harness connector.





Does continuity exist?
YES - GO TO 10
NO - Repair the harness or connector.
10.CHECK DAYTIME LIGHT RELAY 1 GROUND CIRCUIT
Check continuity between daytime light relay 1 harness connector and ground.





Does continuity exist?
YES - GO TO 11
NO - Repair the harness or connector.
11.CHECK DAYTIME LIGHT RELAY 1
Check daytime light relay 1. Daytime Light Relay Circuit
Is the inspection result normal?
YES - Replace IPDM E/R. Service and Repair.
NO - Replace daytime light relay 1.




Component Inspection
1. CHECK DAYTIME LIGHT RELAY 2
1. Turn ignition switch OFF.
2. Remove daytime light relay 2.
3. Check the continuity between daytime light relay 2 terminals under the following conditions.





Is the inspection result normal?
YES - Inspection End.
NO - Replace daytime light relay 2.