Code S031 - Speed-Sensitive Steering Short To Ground: Description

SSS short to ground errors are detected via a single error feedback signal which follows a high side switch. This switch is turned on and off at 125 Hz with a duty cycle that varies based on vehicle speed and feedback current between 5 and 95 percent duty cycle.

This PWM causes the driver to experience less steering assist as duty cycle increases with vehicle speed, resulting in more current flow to the SSS solenoid. The RSS module monitors this feedback through both possible PWM states. Duty cycles do not range from 0 to 100 percent to ensure some OFF (95 percent) or some ON (5 percent) is always present so all error conditions can be decoded.

Since a short to ground is potentially destructive to the high side circuitry in the RSS module, an error detection yields a 0 duty cycle very rapidly, and a cool-down time is allotted before another attempt is made to drive the SSS solenoid. Multiple attempts are required to supply filtering to avoid false errors from being detected.

If a specific number of consecutive errors occurs, the SSS PWM is set to 0 percent duty cycle for the remainder of the ignition cycle. The default mode for the SSS valve is full assist with 0 percent duty cycle which yields no current.