DTC C0577, DTC C0578, DTC C0579, DTC C0582, DTC C0583, DTC C0584, DTC C0587, DTC C0588, DTC C0589, DTC C0592, DTC C0593 Or DTC C0594: Damper Solenoid Circuit Low, High Or Open

The RTD module sends a Pulse Width Modulated (PWM) signal to shock absorbers to control damping. Occasionally, to test the integrity of the system, the RTD module commands each shock to a predetermined PWM duty cycle. It then looks at voltage on the solenoid trigger wire and can determine if a malfunction is present. If high voltage (short to voltage) is detected on 2 separate tests, RTD module sets a code for the corresponding shock absorber (C0578, C0583, C0588 or C0593). If low voltage (short to ground) is detected on 2 separate tests, RTD module sets a code for the corresponding shock absorber (C0577, C0582, C0587 or C0592). If low voltage (open circuit) is detected on 2 separate tests, RTD module sets a code for the corresponding shock absorber (C0579, C0584, C0589 or C0594). The RTD module will then command the PWM duty cycle for the failed shock absorber to zero, causing a soft ride on that shock. It will also send a message to the IPC, to display SERVICE RIDE CONTROL and SHOCKS INOPERATIVE messages.

1. Perform RTD diagnostic system check. See RTD DIAGNOSTIC SYSTEM CHECK  under DIAGNOSIS & TESTING. After performing RTD diagnostic system check, go to next step.
2. Disconnect applicable shock absorber connector. See DIAGNOSTIC TROUBLE CODE DEFINITIONS  . Measure resistance between solenoid terminals (solenoid side of connector). If resistance is 9.5-15.5 ohms, go to next step. If resistance is not 9.5-15.5 ohms, replace applicable shock absorber. See SHOCK ABSORBER  under REMOVAL & INSTALLATION. After repairs, go to step  11 .
3. Turn ignition on. Connect test light between ground and supply circuit of appropriate shock absorber solenoid. See WIRING DIAGRAMS  . If test light illuminates, go to next step. If test light does not illuminate, go to step  10 .
4. Connect test light between shock absorber solenoid terminals. Using scan tool, command shock absorber ON and OFF. If test light turns on and off with each command, go to step  8 . If test light does not turn on and off, go to next step.
5. If test light remains illuminated with each command, go to step  7 . If not, go to next step.
6. Check control circuit of shock absorber for open or short to voltage. See WIRING DIAGRAMS  . If open or short to voltage is present, repair and go to step  13 . If open or short to voltage is not present, go to step  9 .
7. Check control circuit of shock absorber for short to ground. See WIRING DIAGRAMS  . If short to ground is present, repair and go to step  13 . If short to ground is not present, go to step  9 .
8. Check for poor connections at harness connector of shock absorber solenoid. If poor connection is present, repair and go to step  13 . If poor connections are not present, go to step  11 .
9. Check for poor connections at harness connector of RTD module. If poor connection is present, repair and go to step  13 . If poor connections are not present, go to step  12 .
10. Repair supply circuit of shock absorber solenoid. See WIRING DIAGRAMS  . Go to step  13 .
11. Replace applicable shock absorber. See SHOCK ABSORBER  under REMOVAL & INSTALLATION. Go to step  13 .
12. Replace RTD control module. See RTD CONTROL MODULE  under REMOVAL & INSTALLATION. After repairs, go to next step.
13. Turn ignition off. Connect or install any connector or components that were disconnected or removed. Turn ignition on. Using scan tool, clear all DTCs. Operate vehicle. Repeat self test. If DTCs reset go to step  2 . If DTCs do not reset, system is okay.