Ford recalls 550k 2014 F-150s for uncommanded downshifts

Ford is recalling 552,188 examples of the 2014 F-150 to address a transmission defect that can lead to random downshifts into first gear at any vehicle speed. A sudden downshift to first gear at high speed can lead to a loss of control and/or potentially immobilizing the vehicle. Ford says a misbehaving driveline sensor is the culprit.

"Some vehicles may experience an intermittent loss of the transmission Output Shaft Speed (OSS) sensor signal to the Powertrain Control Module (PCM), potentially resulting in a temporary, unintended downshift into first gear," Ford's recall report said. "Depending on the vehicle speed at the time of an intermittent OSS failure, an abrupt transmission downshift to first gear could occur. A downshift to first gear without warning could result in a loss of vehicle control, increasing the risk of a crash."

Complicating the issue is the fact that Ford has identified multiple causes for OSS signal issues (contamination, power short to ground, connector corrosion, connector pin swaging, and incorrect outputs from the OSS sensor), so there's no single way to directly remedy the problem. Instead, Ford is updating the shift logic to include a "plausibility check" that will make sure the speed being indicated by the OSS actually makes sense before commanding an automatic shift into first gear. If this all rings a bell, previous model years of the F-150 were subject to a recall for the same issue.