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.
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HOMESERVICE MANUALSTOYOTA2025HIGHLANDER HYBRID XLEREPAIR AND DIAGNOSIS (SINGLE PAGE)ACCESSORIES & EQUIPMENTHEADLIGHTSLIGHTING SYSTEM (W/ AFS) - DIAGNOSTIC CODES (1 OF 2)LIGHTING SYSTEM (W/ AFS)DTC B242C-04: HEADLIGHT CONTROL MODULE (SUB) SYSTEM INTERNAL FAILURE; DTC B242D-04: HEADLIGHT CONTROL MODULE (MAIN) SYSTEM INTERNAL FAILURE [11/2023 - ]DESCRIPTION
2025 Toyota Highlander Hybrid XLE
DTC B242C-04: Headlight Control Module (Sub) System Internal Failure; DTC B242D-04: Headlight Control Module (Main) System Internal Failure [11/2023 - ]: Description
2025 Toyota Highlander Hybrid XLESECTION Description
The headlight ECU sub-assembly LH or headlight ECU sub-assembly RH stores a DTC if it detects an internal malfunction.
| DTC No. | Detection Item | DTC Detection Condition | Trouble Area | DTC Output from |
|---|---|---|---|---|
| B242C-04 | Headlight Control Module (Sub) System Internal Failure | Detection condition:
Malfunction status:
Malfunction duration:
|
Headlight ECU sub-assembly RH | Headlight Control (Sub) |
| B242D-04 | Headlight Control Module (Main) System Internal Failure | Detection condition:
Malfunction status:
Malfunction duration:
|
Headlight ECU sub-assembly LH | Headlight Control |
RENDER: 1.0x
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.