P0635 indicates that the power steering control module has detected an abnormal voltage or signal in the power steering control circuit. This circuit supplies power and communication to the electric power steering motor or hydraulic pump solenoid, and a fault can result in reduced or lost steering assist.
Internal circuitry or driver transistors in the module can fail, causing an open or short in the control circuit.
Chafed, corroded, or disconnected wires and pins between the module, pump/motor, and power supply are common sources of the code.
A loss of supply voltage will trigger the module to set P0635.
An internal short or open in the actuator can feed back an abnormal signal to the control module.
High resistance or intermittent ground paths can cause voltage irregularities detected by the module.
Rare; a loss of CAN communication or erroneous data from the PCM can cause the power steering module to set the code.
No. The PCM is rarely the root cause; most often the fault lies in the power steering control module, its wiring, fuses, relays, or the steering actuator itself.
Yes. Insufficient system voltage can cause the power steering control module to detect a circuit fault and set the code.
Clearing the code only removes the stored fault; the underlying circuit issue will cause the code to return until the root cause is repaired.
Steering assist may be reduced or lost, making the vehicle harder to control, especially at low speeds. The vehicle should be diagnosed and repaired promptly.