Automatic Headlight Sensor Circuit
2014-2016 Tesla Model S P85D Dual Motor AWD 🇩🇪
Description
Malfunction in the automatic headlight ambient light sensor circuit.
Symptoms
- Auto headlights not turning on in tunnels/darkness
- Headlights on in bright daylight
- Auto headlight feature disabled
- Dash light sensor not adjusting brightness
Common Causes
- Faulty ambient light sensor
- Sensor covered by dashboard object
- Wiring damage
- BCM auto-light module fault
- Sensor window dirty
Diagnostic Steps
- Check light sensor reading with scan tool
- Clean sensor lens on dashboard
- Inspect sensor wiring
- Test BCM auto headlight output
- Verify feature is enabled in settings
Repair Notes
Replace ambient light sensor or clean sensor window. Check that nothing is covering the sensor on the dash top.
Related Codes
Other Body Codes
- B0001Driver Frontal Stage 1 Deployment Control
- B0002Driver Frontal Stage 2 Deployment Control
- B0003Passenger Frontal Stage 1 Deployment Control
- B0004Passenger Frontal Stage 2 Deployment Control
- B0005Driver Knee Airbag Deployment Circuit
- B0006Passenger Knee Airbag Deployment Circuit
- B0007Rear Left Side Airbag Deployment Circuit
- B0008Rear Right Side Airbag Deployment Circuit
- B0009Rear Center Airbag Deployment Circuit
- B0010Driver Side Airbag Deployment
B2100 on Other Vehicles
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2024-2024 Cyberbeast Tri Motor AWD
Tesla Cybertruck
2024-2024 Dual Motor AWD
Tesla Cybertruck
2024-2024 Single Motor RWD
Tesla Model 3
2017-2020 Long Range Dual Motor AWD
Tesla Model 3
2017-2020 Performance Dual Motor AWD
Tesla Model 3
2017-2020 Standard Range Plus Single Motor RWD
Tesla Model 3
2021-2024 Long Range Dual Motor AWD
Tesla Model 3
2021-2024 Performance Dual Motor AWD
Common Questions
What does code B2100 mean on a 2014-2016 Tesla Model S?
B2100 stands for "Automatic Headlight Sensor Circuit". Malfunction in the automatic headlight ambient light sensor circuit.
What are the symptoms of B2100 on a Tesla Model S?
Common symptoms of B2100 include: Auto headlights not turning on in tunnels/darkness, Headlights on in bright daylight, Auto headlight feature disabled, Dash light sensor not adjusting brightness.
What causes B2100 on a 2014-2016 Tesla Model S?
Common causes of B2100 include: Faulty ambient light sensor, Sensor covered by dashboard object, Wiring damage, BCM auto-light module fault, Sensor window dirty.