NHTSA Complaint #11628590 — 2017 FORD FOCUS

While changing a dead battery, the vehicle's transmission control module (TCM) malfunctioned and caused the shift drum to shear off a piece of the aluminum casing inside the gearbox. DTC codes P2837 and P287B were present indicating a shift fork failure. The dual-clutch transmission (DPS6) lost access to reverse, 2nd gear and 4th and 6th gear, but was still able to shift into 1st, 3rd and 5th. Under these conditions, there is the possibility that the sheared off piece of aluminum can enter the gear train and cause the transmission to seize, putting passengers life at risk. The problem is either that the aluminum casing is deficient, or, more likely, that the TCM software is flawed. The problem has been confirmed by the local Ford dealership, who took pictures of the damage, including the piece of aluminum. Judging from Internet search results for the DTCs, the problem is widespread and triggered by a low battery or weak (high impedance) ground condition in the TCM. No warning lights or low battery indications were shown prior to the incident.