DTC C1658: EEPROM Calibration Malfunction

When ign switch is turned on, ESC performs internal self diagnostic check. If an internal (inside the ESC controller) fault related to the EEPROM is discovered it sets DTC C1658. Based on this fault, any or all of the following actions may be taken. Command 0% PWM duty cycle disabling all four shock absorbers. Ignores steering position input. Controls shock absorber based solely upon vehicle speed input. Sends message to IPC (instrument panel control) to display "Service Ride Control" and/or "Shocks Inoperative" message. If the disable all four shock absorber action was taken, the ESC module sends a message to the PCM (Powertrain Control Module) to limit vehicle speed to 80 MPH.

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. Using scan tool or IPC, clear all DTCs. Cycle ignition off then on. Using scan tool, check for DTCs. If DTC C1658 is set, go to next step. If DTC C1658 is not set, system is functioning properly.
3. Replace RTD control module. See RTD CONTROL MODULE  under REMOVAL & INSTALLATION. After repairs, go to next step.
4. Turn ignition off. Connect or install any connector or components that were disconnected or removed. Turn ignition on. Using scan tool, clear all DTCs.