S032

CODE S032 SSS SOLENOID SHORT ACROSS LOAD









TEST CONDITIONS:
The RSS control module monitors the amount of current through the SSS solenoid via a low-side feedback and monitors the PWM signal through a high-side feedback during both the on and off portions of the PWM drive signal. The module expects to see the high-side low and a normal current reading during the off portion of the PWM mode. Additionally, the module expects to see the high-side high and a normal current reading during the on portion of the PWM mode.

FAULT CONDITIONS:
If the RSS control module sees the high-side high during an off state and one of the following conditions for three consecutive samples (samples taken at five second intervals), a code is set.
1. The high-side high and a low current reading during an "ON" state.
2. The high-side high and a high current reading during an "ON" state.

ACTION TAKEN:
The RSS control module will de-energize the solenoid within the first 1 mS of the sample in which a fault is detected. The system will attempt to drive the solenoid again once the vehicle speed equals 0 and 5 seconds have passed since the last retry. During the retry the feedback signals are resensed, and if the feedback signals are correct, normal operation is resumed. Otherwise, the "stop-wait-retry-sense" sequence is repeated. A software counter is incremented each time a fault is detected or decremented for each time a fault is not detected. If the counter reaches the count of three at any time, a code is set, the message "SERVICE RIDE CONTROL" is displayed, and the solenoid is de-energized for the remainder of the ignition cycle.

DESCRIPTION:
The RSS control module adjusts the steering effort to a desired level as a function of vehicle speed by controlling the amount of current to the steering control solenoid. Current is controlled by switching the solenoid's high-side to battery through solid-state circuitry. This circuitry is operated at 125 Hz and with a PWM that varies based upon vehicle speed and feedback current between 5% and 95%. Thus, as vehicle speed increases, so does the duty cycle ofthe switching circuit resulting in more current flow to the SSS solenoid and therefore less steering assist. Faults are detected by a high-side (discrete) and a low-side (analog) feedback signal connected to the solenoid drive and solenoid return line, respectively. The RSS module monitors these feedback lines through both the on and off portions of the PWM drive signal. Since a short to voltage is potentially destructive to the low-side circuitry in the module, a fault detection yields a 0% duty cycle very rapidly and being allowed to cool down before another attempt is made to drive the solenoid. Multiple attempts are made to avoid false errors, and if a specific number of consecutive errors occur, the solenoid is de-energized for the remainder of the ignition cycle. The default mode for the SSS solenoid is full assist with 0% duty cycle, which yields no current.

NOTES ON FAULT TREE:
[1] Refer to notes on intermittents.
[2] Replace steering system fluid filter whenever the SSS solenoid is replaced.
[3] Refer to clearing codes.

IMPORTANT:
^ DO NOT BACKPROBE SENSORS, DAMPERS, OR ELC / RSS CONNECTORS.
^ WHEN ALL DIAGNOSIS AND REPAIRS ARE COMPLETE, CLEAR CODES AND VERIFY OPERATION.