Reference meaning
What does this code mean?
The wording below belongs to the named make and communication. Match the complete code, reporting module, model year and engine before applying it.
A code identifies a detected condition, not a part that must automatically be replaced.
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A listed vehicle is a research lead. Confirm the engine, production range and software in the manufacturer's information.
Before replacing a part
Record codes and freeze-frame data. Check battery condition, related codes and visible wiring or hose damage. Follow the vehicle's diagnostic procedure and test results before replacing parts.
Scan worksheet →Manufacturer wording
Source wording can vary by vehicle and suffix. It is shown as written, not as a universal diagnosis.
B123Fautomatic lighting control unit/sunlight sensor error
Manufacturer communications
1Original wording in English
HONDA
ServiceNews Article - The 2020 CR-V comes with two backup fuses: No. 18 BACK UP (10A) and No. 27 BACK UP 2 (30A). If you pull the No. 27 fuse (or it's blown), and turn the ignition to ON while leaving the No. 18 fuse intact, it will set DTC B123F (automatic lighting control unit/sunlight sensor error).
Check vehicle applicability
1A listed vehicle is a research lead. Confirm the engine, production range and software in the manufacturer's information.
| Make | Model | Model year |
|---|---|---|
| Honda | CR-V ↗ | 2020 |
Can I keep driving?
A code alone cannot establish whether driving is safe. A flashing malfunction light, severe shaking, overheating, oil-pressure warning or loss of braking or steering needs prompt attention. Stop in a safe place and seek assistance when control or engine safety is affected. Follow the vehicle handbook.