Normal Operation

WARNING: This page is about a different car, the 2010 Mercury Mariner and 2010 Ford Escape. However, it is still accessible from the selected car via links, so may be relevant.

The voltage required for correct Electronic Power Assist Steering (EPAS) system operation is 11-16 volts. The power steering motor, torque sensor and steering shaft/wheel position sensor are all integrated into the Power Steering Control Module (PSCM) and the PSCM is integrated into the steering column. If any new components need to be installed, a new steering column must be installed.

Fused ignition voltage is supplied to the PSCM by Smart Junction Box (SJB) fuse 35 (10A) along circuit CBP35 (YE/GY). Fused battery voltage for the power steering motor is supplied to the PSCM by Battery Junction Box (BJB) 80A MIDI (WH) fuse along circuit SBB01 (RD). Ground for the PSCM is provided along circuit GD116 (BK/VT). The PSCM communicates with the other vehicle control modules along the High Speed Controller Area Network (HS-CAN) bus, circuits VDB04 (WH/BU) and VDB05 (WH).

DTC B2277 (Electric Power Steering Motor Malfunction) - An open or short in the PSCM power or HS-CAN bus circuits will cause the appropriate DTC to set. Also, an internal failure of the steering shaft torque sensor, shaft position sensor or motor will cause the DTC to set.
DTC B2278 (Steering Shaft Torque Sensor Malfunction) - An open or short in the PSCM power or HS-CAN bus circuits will cause the appropriate DTC to set. Also, an internal failure of the steering shaft torque sensor, shaft position sensor or motor will cause the DTC to set.
DTC B227B (Steering Shaft Position Sensor Malfunction) - An open or short in the PSCM power or HS-CAN bus circuits will cause the appropriate DTC to set. Also, an internal failure of the steering shaft torque sensor, shaft position sensor or motor will cause the DTC to set.
This pinpoint test is intended to diagnose the following:
Wiring, terminals or connectors
PSCM