NHTSA Preliminary Evaluation PE14030

The Office of Defects Investigation (ODI) opened a preliminary evaluation to investigate complaints of the loss of power steering while driving. The subject vehicles are equipped with a rack mounted Electric Power Assisted Steering (EPAS) unit.Some of the complaints alleged that the steering assist failed and resulted in increased steering efforts that contributed to a loss of control and in some cases a crash.The EPAS system was manufactured by TRW Automotive for Ford and was designated as Generation I.These units were first produced and put into vehicle production in July 2008 beginning with the model year (MY) 2010 Ford Fusion and Mercury Milan.The system is comprised of a mechanical steering rack-and-pinion gear with torque sensor, electric assist motor, motor position sensor and a power steering control module (PSCM). The PSCM is self-monitoring and designed to detect faults within the system and can store diagnostic trouble codes (DTCs) if a problem is detected.There are 29 potential DTCs the system can detect.Many of these allow the system to go into reduced-assist steering mode by using the default vehicle speed signal should the live speed signal be lost, if voltage to EPAS system falls below 10.7 or goes above 17 volts, the temperature at the PSCM goes above 105C (221F), or if high friction is detected.Some DTCs will cause the system to go into manual steering mode (no assist). On July 1, 2015, Ford filed a Defect Information Report (DIR) identifying a safety related defect in TRW GEN I EPAS systems installed in some of the subject vehicles (NHTSA Recall 15V-340, Ford No. 15S18).The DIR indicated that intermittent electrical connections caused by quality issues associated with conformal coat contamination and ribbon cable pin misalignment within the steering gear motor may lead to a loss of the motor position sensor signal, resulting in a sudden loss of power assist while driving.The recall covers approximately 393,623 vehicles built from September 2010 th