C0691

DTC C0691





Circuit Description
Shock absorber solenoid voltage is supplied to the ESC module through the RTD relay circuit. The ESC module controls the RTD relay by grounding the RTD relay control circuit. This closes the relay contacts providing each shock absorber solenoid with supply voltage through the ESC module's internal solenoid supply circuitry. Each individual solenoid control then controls the operation of the corresponding shock absorber. The ESC module monitors the RTD relay control/solenoid supply circuits for any malfunction conditions.

Conditions for Running the DTC
^ The ignition ON.
^ The RTD function enabled.

Conditions for Setting the DTC
^ The ESC module detects low voltage (an open or a short to ground) on the RTD relay control circuit.
^ Detection for this DTC can only be accomplished during the OFF (relay not applied) state.

Action Taken When the DTC Sets
^ Stores a DTC C0691 in the ESC memory.
^ Commands 0% PWM duty cycle in order to disable all four solenoids.
^ Sends a message to the IPC to display the SERVICE RIDE CONTROL and the SHOCKS INOPERATIVE messages.
^ Sends a message to the PCM to limit the speed. The PCM then sends a massage to the IPC to display the MAXIMUM SPEED 129 km/h (80 mph) message.

Conditions for Clearing the DTC
^ The ignition must be cycled before this DTC can change from current to history even if the malfunction is no longer present.
^ The ESC module no longer detects low voltage, which is an open or a short to ground on the RTD relay control circuit with the relay OFF
^ A history DTC will clear after 100 consecutive ignition cycles if the condition for the malfunction is no longer present.
^ The IPC clearing DTCs feature.
^ Using a scan tool.

Diagnostic Aids
^ The following conditions may cause an intermittent malfunction:
- An open or a shot to ground on the RTD relay control circuit.
- An open RTD relay coil or high resistance condition.
- An open RTD relay fuse #7.
- A short to ground on any shock absorber solenoid supply circuit.
^ The RTD relay may be installed in the underhood electrical center in two directions and still function properly.
^ The RTD relay provides supply voltage to all four shock absorber solenoids. Therefore, multiple shock absorber solenoid open or short to ground DTCs may also be stored along with a DTC C0691.

Test Description
The numbers below refer to the step numbers on the diagnostic table.
2. Tests for voltage at the coil side of the RTD relay.
3. Verifies that the ESC module is providing ground to the RTD relay.
4. Tests if ground is constantly being applied to the RTD relay.
5. Tests for an open in the RTD control circuit.