SSM 51316

Some 2020-2022 F-Super Duty vehicles equipped with a 6.7L engine may exhibit an illuminated malfunction indicator lamp (MIL) with diagnostic trouble code (DTC) P1674 stored in the transmission control module (TCM). This may be due to a discharged battery and/or low battery state of charge. Before performing normal diagnostics in Workshop Manual (WSM), Section 307-01, charge and test the battery/batteries using the Ford approved battery test equipment listed in the Ford Warranty and Policy Manual. Replace the battery/batteries if directed by the test equipment. Clear DTCs and perform the self test again. If P1674 returns, refer to WSM, Section 307-01 for normal diagnostics. If P1674 does not return, use the Report a Vehicle Concern link at the bottom of OASIS to submit a report that will assist with the engineering investigation.