Mercedes-Benz B17D149
The "Adaptive interior lighting" control unit for the rear left roof has malfunctioned. There is an internal electrical fault. • E48/4 (Adaptive rear interior lamp, roof, center) /
Quick answer
B17D149 indicates an internal electrical fault in the adaptive interior-lighting control unit associated with the rear-left roof lamp. Verified applicability: 2022–2023 Mercedes-Benz EQS, US.
This page separates verified manufacturer/regulator evidence from supporting material. Unsupported causes, repairs or safety conclusions are not guessed.
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1. What does B17D149 mean?
B17D149 indicates an internal electrical fault in the adaptive interior-lighting control unit associated with the rear-left roof lamp. Verified applicability: 2022–2023 Mercedes-Benz EQS, US.
2. Technical explanation
Mercedes-Benz DTC B17D149 is defined as: “The ‘Adaptive interior lighting’ control unit for the rear left roof has malfunctioned. There is an internal electrical fault.” The supplied official NHTSA manufacturer communication identifies this as involving E48/3, the adaptive rear interior lamp, roof, left. The diagnostic title also references E48/4; however, the supplied bulletin evidence specifically associates B17D149 with E48/3 and associates B17D349 with E48/4.
3. What system is affected?
Adaptive rear-compartment interior lighting; specifically the rear-left roof lamp/control-unit location (E48/3) according to the supplied official manufacturer communication.
4. How serious is this code?
Not yet established by verified evidence.
5. Symptoms you may notice
- Adaptive rear-compartment lighting may be sporadically inoperative.
- One or more rear interior lamps may be affected, according to the supplied manufacturer communication.
6. Possible causes
- An internal electrical fault in the adaptive interior-lighting control unit for the rear-left roof lamp is established by the DTC definition.
7. Can I still drive the vehicle?
Not yet established by verified evidence.
8. Can I charge the vehicle?
Not yet established by verified evidence.
9. What you can safely do
- Arrange diagnosis by an authorized Mercedes-Benz service provider if the rear adaptive interior lighting is intermittently inoperative or B17D149 is stored.
- Do not attempt high-voltage-system repairs. The verified evidence does not identify the high-voltage system as involved.
10. Step-by-step troubleshooting
- A qualified technician can confirm whether B17D149 is stored and evaluate the adaptive rear interior-lighting concern. Further diagnostic steps are not provided in the supplied verified evidence.
11. When to contact service
Contact a Mercedes-Benz authorized service provider for diagnosis of stored B17D149 or sporadically inoperative rear adaptive interior lighting.
12. What the service center may check
- Check for stored B17D149 in connection with the adaptive rear-left roof interior lamp/control unit (E48/3).
- Evaluate the reported sporadic operation of rear-compartment adaptive interior lighting. Additional service checks are not established by the supplied evidence.
13. Possible repair or resolution
- Not yet established by verified evidence.
14. Affected vehicles
- Mercedes-Benz EQS · 2022–2023 · US
15. Related TSBs / service bulletins
- NHTSA Manufacturer Communication 11018613, Mercedes-Benz LI82.20-P-079313, published May 22, 2025. It describes sporadically inoperative adaptive rear-compartment lighting and lists B17D149 for E48/3, the adaptive rear interior lamp, roof, left.
16. Recall information
- Not yet established by verified evidence.
17. Official manufacturer information
Verified official source: NHTSA Manufacturer Communication 11018613, Mercedes-Benz LI82.20-P-079313: https://static.nhtsa.gov/odi/ffdd/tsbs/TSBS_RECEIVED_2025-2026.zip#nhtsa_id=11018613
19. Frequently asked questions
What does Mercedes-Benz code B17D149 mean?
It means the adaptive interior-lighting control unit for the rear-left roof has malfunctioned due to an internal electrical fault.
Which vehicles are verified as applicable?
The supplied database evidence lists US-market 2022–2023 Mercedes-Benz EQS vehicles.
What symptom is documented?
The official manufacturer communication documents adaptive rear-compartment lighting that is sporadically inoperative.
Is this a recall?
Not yet established by verified evidence.