FORD · 2019-11-01
Some 2017-2019 F-Super Duty 4x4 vehicles may exhibit an inoperative transfer case function with various diagnostic trouble codes (DTCs), including but not limited to P1839, P1867, P1861, P1891, P1841, U0102. If normal diagnosis leads to shift motor as the cause, first disconnect transfer case control module (TCCM) connector C2371A, and inline connectors C1010 (diesel) or C145 (gasoline) as well as transfer case connector C350. Inspect for loose pins, contamination and broken wires and repair as necessary. If nothing is found, reconnect and test 4x4 operation.