{"nhtsa_id":11021897,"type":"service_bulletin","type_name":"Service bulletin","date_added":"2025-08-15","date":"2025-08-04","document_id":"LI54.21-P-078926","mfr_campaign":null,"replaces":null,"component":"ENGINE","mfr_system":null,"summary":"Complaint: Check engine light comes on when driving/starting the vehicle. No drivability concerns. Cause: Communication error in G1/3 - 48 V on-board electrical system battery (48 V LIB) or N127 - 'Drivetrain' control unit (PTCU)saved and/or current Remedy: Update the software for the control unit G1/3 - 48 V on-board electrical system battery (48 V LIB) : --> Remedy-SW A001902042425/12 If the fault profile still occurs with the installed software, check the wiring and the plug contacts: UG1/3 - 48 V on-board electrical system battery (48 V LIB) N83/1 - DC/DC converter (DDW) N127 - 'Drivetrain' (PTCU) control unit NOTE: Replacing parts does not remedy the problem.","document":{"url":"https://static.nhtsa.gov/odi/tsbs/2025/MC-11021897-0001.pdf","alternate_url":"https://static.nhtsa.gov/odi/tsbs/2025/MC-11021897-9999.pdf","confirmed":false},"url":"https://open.wenmarpro.com/bulletins/11021897","components":[{"id":"engine","name":"Engine","parent":null}],"codes":[],"topics":[],"vehicles":[{"make":"MERCEDES-BENZ","model":"AMG CLA35","year_from":2020,"year_to":2024,"match":null,"vehicle_ids":[]},{"make":"MERCEDES-BENZ","model":"AMG CLA45","year_from":2020,"year_to":2024,"match":null,"vehicle_ids":[]},{"make":"MERCEDES-BENZ","model":"AMG GLA45","year_from":2021,"year_to":2023,"match":null,"vehicle_ids":[]},{"make":"MERCEDES-BENZ","model":"AMG GLB35","year_from":2021,"year_to":2025,"match":null,"vehicle_ids":[]},{"make":"MERCEDES-BENZ","model":"CLA 250","year_from":2020,"year_to":2025,"match":null,"vehicle_ids":[]},{"make":"MERCEDES-BENZ","model":"GLA 250","year_from":2021,"year_to":2025,"match":null,"vehicle_ids":[]},{"make":"MERCEDES-BENZ","model":"GLA 250 4MATIC","year_from":2024,"year_to":2024,"match":null,"vehicle_ids":[]},{"make":"MERCEDES-BENZ","model":"GLB 250","year_from":2020,"year_to":2025,"match":null,"vehicle_ids":[]}],"as_of":"2026-10-19","note":"A bulletin is a manufacturer's communication to its dealers, as NHTSA indexes it. The summary is NHTSA's. The document is the manufacturer's: read it at NHTSA. A bulletin is not a recall, and listing a model year does not mean every vehicle of it is concerned.","attribution":[]}