Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
DTC B1085
DTC B1085 : Head Light Low Beam Power Source Abnormality
NOTE: If you are troubleshooting multiple DTCs, be sure to follow the instructions in B-CAN System Diagnosis Test Mode A .
| DTC Description | DTC |
|---|---|
| B1085 Head Light Low Beam Power Source Abnormality |
DTC (Relay Control Module)
- Problem verification
-1. Clear the DTCs with the HDS.
-2. Turn the combination light switch to the ON position.
-3. Wait for at least 6 seconds.
-4. Check for DTCs with the HDS.
DTC Description DTC B1085 Head Light Low Beam Power Source Abnormality Is DTC B1085 indicated?
YES
Go to step 2.
NO
Intermittent failure, the system is OK at this time.
- Headlight operation check
-1. Turn the combination light switch ON position then check the status of the headlights.
Does one side of headlight go off?
YES
Go to step 3.
NO
Go to step 4.
- Headlight check
-1. Swap the left headlight and the right headlight .
Are the symptoms swapped left and right?
YES
Replace the failure headlight .
NO
- Shorted wire check (H/L_LO_SIG line)
-1. Turn the vehicle to the OFF (LOCK) mode.
-2. Disconnect the following connectors.
Relay control module connector B (10P)
Left headlight 8P connector
Right headlight 8P connector-3. Measure the resistance between test points 1 and 2.
Test condition Vehicle OFF (LOCK) mode
Relay control module connector B (10P): disconnected
Left headlight 8P connector: disconnected
Right headlight 8P connector: disconnectedTest point 1 Relay control module connector B (10P) No. 9 Test point 2 Body ground Is there 1.0 MΩ or more?
YES
Replace the relay control module .
NO
Repair a short to ground in the wire.
NO RELATED
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When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- • You smell fuel, burning insulation, or see smoke.
- • Brakes feel soft, pull hard to one side, or make grinding noises.
- • The engine overheats, stalls repeatedly, or misfires under load.
- • You are missing required tools, torque specs, or safe lifting equipment.
- • You are not confident in the next step or safety outcome.