The electronic variable orifice (EVO) on DOHC engines varies the power steering pressure flow from the power steering pump. The PCM controls the steering assist solenoid by pulse width modulating (PWM) ignition voltage to the solenoid. The low side of the steering assist solenoid is tied directly to a low resistance resistor, which is tied directly to ground in the PCM. The PCM monitors the steering assist solenoid circuit for low and high voltage faults at all times (Off, On and PWM). DTC P0636 sets when the steering assist solenoid is commanded On or commanded to PWM (On-time only) and the feedback voltage at the PCM is low.

DTC P0636 will set if the steering assist solenoid voltage is less than 3 volts when steering assist solenoid is commanded On.

DTC P0636 diagnostic runs continuously with ignition On and steering assist solenoid commanded On.

DTC P0636 is a type D DTC.

To locate an intermittent problem, use Scan tool to command STEERING ASSIST SOLENOID On (No Assist), while monitoring the STEERING SOL. - LOW VOLT test. When a fault (short to ground or shorted solenoid) exists, the Scan tool will display TEST FAIL.

The test will fail only when the device is being commanded On and the voltage at the PCM is low. The test updates every 100 ms whenever the ignition is turned On and the device is being commanded On via the scan tool or PCM.

Steering assist solenoid resistance: 8-12 ohms.