Technical Service Bulletin SSM 53966 — 2023 FORD F-550 SD

Some 2021-2025 Ford/ Lincoln vehicles equipped with SYNC4 may not be able to perform an update to the accessory protocol interface module (APIM). This may be due to the software in the APIM. Ford Engineering has de-activated the ability to update these SYNC4 APIM modules as applicable, and the Ford Diagnosis and Repair System (FDRS) will not present an update for the APIM module. Some existing directed repairs may be impacted, check Professional Technician System (PTS) before attempting any specific technical service bulletin (TSB)/special service message (SSM) and check field service action (FSA) landing pages before attempting any FSA repairs. For any vehicle repairs requiring a software update that includes an APIM update in the programming sequence, if the 5-digit product code for the APIM software is equal to or lower than 23187, do not attempt to update affected modules at this time. To determine the 5-digit product code for the APIM software on the vehicle, while the vehicle center display screen is powered up with ignition in run or accessory, go to Settings > General > About SYNC.