What causes a P0635 code?

P0635 can be triggered by several issues — see the verified probable causes and step-by-step diagnostics shared by mechanics and owners on OBDIY.

Can I drive with a P0635 code?

Drivability depends on the severity. Check the severity rating and verified driver reports on this page before continuing to drive with P0635 active.

Follow the step-by-step diagnostic on this page, then read the verified fixes contributed by other Heavy Truck owners — the answer marked "Verified Cause" worked for the original poster.

OBDIY

OBD-II

P0635

Power Steering Control Circuit Malfunction

What it means

The Engine Control Module (ECM) has detected an abnormal voltage or current reading in the power steering control circuit, typically affecting trucks equipped with electronic variable orifice or assist sensors.