Code S028, Right Rear Damper Solenoid Short Across Load: Description

To produce a soft damper setting, the solenoids high side is switched to battery voltage to allow the solenoid to move to the open position. After this initial pull in, the high side of the solenoid is the pulse width modulated to hold the valve in the open state while reducing current draw.

Finally, this switch is turned off to close the valve. This produces a firm damper setting. The firm mode is produced with an OFF state, and the soft mode is produced by a combination of boost and hold states.

The soft and firm settings toggle based on various road conditions to provide optimal ride and handling.

Shorts across solenoid are detected by a high side and low side feedback signal connected to the damper drive and damper return line. The RSS module monitors these discrete feedbacks through all possible states (On, Off, PWM High State, and PWM Low State).

Since a short across load is destructive to the high side circuitry, error detection quickly yields a firm damper setting, and a cool-down time is allotted before another attempt is made to drive the solenoid. Multiple attempts are required to supply filtering to avoid false errors from being detected.

If a specific number of consecutive errors occurs, all four (4) dampers are set to firm for the remainder of the ignition cycle. The default mode for the damper solenoid is closed to produce a firm damping level when no current is applied.

1. See NOTES ON INTERMITTENTS  under TESTING & DIAGNOSIS.
2. A short to battery in circuit No. 1118 or a short to ground in circuit No. 1119 may damage the windings in the solenoid and create an open.

Fig 1: Right Rear Damper Solenoid Short Across Load (1 of 3)

Courtesy of GENERAL MOTORS CORP.

Fig 2: Right Rear Damper Solenoid Short Across Load (2 of 3)

Courtesy of GENERAL MOTORS CORP.

Fig 3: Right Rear Damper Solenoid Short Across Load (3 of 3)

Courtesy of GENERAL MOTORS CORP.