{"nhtsa_id":10200020,"type":"service_bulletin","type_name":"Service bulletin","date_added":"2021-08-06","date":"2021-07-29","document_id":"NTB21-067","mfr_campaign":null,"replaces":null,"component":"ELECTRICAL SYSTEM; EQUIPMENT ADAPTIVE/MOBILITY; EQUIPMENT","mfr_system":null,"summary":"HIGH FREQUENCY NOISE WITH AUDIO SYSTEM DISPLAY ON IF YOU CONFIRM There is a high frequency (17 kHz) noise with the audio system display screen turned ON, NOTE: • The 17kHz range may not be audible to some people. • Noise can be heard with the audio system ON or OFF. AND The high frequency noise is not heard with the audio system display screen turned OFF, AND Service Comm does not show PM991 applies to the vehicle you are working on. HINT: If Service Comm shows PM991 does apply to the vehicle you are working on, perform PM991 and do not apply this bulletin. ACTION 1. Confirm the current Audio Control Unit software version is 321 or 420. 2. Update the Audio Control Unit software version to 423.","document":{"url":"https://static.nhtsa.gov/odi/tsbs/2021/MC-10200020-0001.pdf","alternate_url":"https://static.nhtsa.gov/odi/tsbs/2021/MC-10200020-9999.pdf","confirmed":false},"url":"https://open.wenmarpro.com/bulletins/10200020","components":[{"id":"electrical","name":"Electrical system","parent":null},{"id":"equipment","name":"Equipment and accessories","parent":null}],"codes":[],"topics":[],"vehicles":[{"make":"NISSAN","model":"SENTRA","year_from":2021,"year_to":2021,"match":"exact","vehicle_ids":["2021_nissan_sentra"]}],"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":[]}