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U3003 on the 2020 Ford F-550

The bulletins listed name this code in NHTSA's summary, or are about the same components. A bulletin or a recall listed here may apply to the model year. None of it is a diagnosis.

Nobody has written a description of this code yet.

Bulletins for this model year that name U3003
TSB 23-21332023-05-04. Service bulletin. Some 2020-2022 F-Super Duty vehicles may exhibit a condition where the engine will not turn off and/or have various electrical symptoms including a dead battery, horn stays on and no crank/no start. The vehicle may also have an illuminated anti-lock braking system (ABS) indicator with diagnostic trouble codes (DTCs) C0020 and U3003 in the ABS module. This may be a result of water/moisture intrusion into the battery junction box (BJB). The BJB is located under the hood of the vehicle. This water/moisture intrusion may be related to the BJB cover not installed completely or broken cover tabs/locking fingers allowing water/moisture into the BJB. To correct the condition, follow the Service Procedure to inspect for water/moisture intrusion into the BJB and replace the BJB and cover if water/moisture intrusion is found.
TSB 22-24432022-12-02. Service bulletin. This article supersedes TSB 22-2313 to update the Parts List, Service Procedure, and vehicle production fix dates. Some 2020-2022 F-Super Duty vehicles may exhibit a condition where the engine will not turn off and/or have various electrical symptoms including a dead battery, horn stays on and no crank/no start. The vehicle may also have an illuminated anti-lock braking system (ABS) indicator with diagnostic trouble codes (DTCs) C0020 and U3003 in the ABS module. This may be a result of water/moisture intrusion into the battery junction box (BJB). The BJB is located under the hood of the vehicle. This water/moisture intrusion may be related to the BJB cover not installed completely or broken cover tabs/locking fingers allowing water/moisture into the BJB. To correct the condition, follow the Service Procedure to inspect for water/moisture intrusion into the BJB and replace the BJB and cover if water/moisture intrusion is found.
TSB 22-20442022-02-23. Service bulletin. Some 2020-2022 F-Super Duty vehicles may exhibit a condition where the engine will not turn off and/or have various electrical symptoms including a dead battery, horn stays on and no crank/no start. The vehicle may also have an illuminated anti-lock braking system (ABS) indicator with diagnostic trouble codes (DTCs) C0020 and U3003 in the ABS module. The vehicle may not shift out of park (P) and/or have continuously illuminated brake lamps with DTCs P0504 and/or C0040. This may be a result of water/moisture intrusion into the battery junction box (BJB). The BJB is located under the hood of the vehicle. This water/moisture intrusion may be related to the BJB cover not installed completely or broken cover tabs/locking fingers allowing water/moisture into the BJB. To correct the condition, follow the Service Procedure steps to inspect for water/moisture intrusion into the BJB and replace the BJB if water/moisture intrusion is found.
TSB 22-20042022-02-04. Service bulletin. Some 2020-2022 F-Super Duty vehicles may exhibit a condition where the engine will not turn off and/or have various electrical symptoms including a dead battery, horn stays on and no crank/no start. The vehicle may also have an illuminated anti-lock braking system (ABS) Indicator with DTCs C0020 and U3003 in the ABS module. This may be a result of water/moisture intrusion into the battery junction box (BJB). The BJB is located under the hood of the vehicle. This water/moisture intrusion may be related to the BJB cover not installed completely or broken cover tabs/locking fingers allowing water/moisture into the BJB. To correct the condition, follow the Service Procedure steps to inspect for water/moisture intrusion into the BJB and replace the BJB if water/moisture intrusion is found.
SSM 501542021-09-28. Service bulletin. Some 2018-2020 Expedition/Navigator, 2015-2020 F150 and 2017-2020 F-Super Duty vehicles equipped with power running boards (PRB) may exhibit a condition where the PRBs are disabled, changing the feature menu setting from Auto to Off mode in the instrumental panel cluster (IPC), DTC U3003:16 stored in the running board control module (RBM) and with or without an illuminated charging system indicator lamp. This may be due to a low battery voltage event or a fully discharged battery. To correct this condition, inspect the charging system and correct the low battery voltage event. Refer to Workshop Manual (WSM), Section 501-08 > Diagnosis and Testing. Configure the PRB system mode from Off to Auto mode in the Advance Settings of the IPC. Refer to the Owner's Manual > Power Running Boards.
TSB 21-21762021-09-02. Service bulletin. Some 2020-2021 F-Super Duty vehicles may exhibit a condition where the engine will not turn off and/or have various electrical symptoms including a dead battery, horn stays on and no crank/no start. The vehicle may also have an illuminated anti-lock braking system (ABS) Indicator with DTCs C0020 and U3003 in the ABS module. This may be a result of water/moisture intrusion into the battery junction box (BJB). The BJB is located under the hood of the vehicle. This water/moisture intrusion may be related to the BJB cover not installed completely or broken cover tabs/locking fingers allowing water/moisture into the BJB. To correct the condition, follow the Service Procedure steps to inspect for water/moisture intrusion into the BJB and replace the BJB if water/moisture intrusion is found.

6 on file from NHTSA, as of 2026-10-19. See them in the bulletin list. A bulletin lists model years: read the document for which vehicles it concerns.