C1717

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Circuit Description
The ESC module uses the Pulse-Width Modulation (PWM) method in order to control each shock absorber solenoid. Switching the voltage ON and OFF at each shock absorber solenoid, or PWM-ing, limits the amount of current supplied to that particular solenoid. The ESC module periodically commands each shock absorber to an set PWM duty cycle in order to override the normal PWM command. During this set PWM duty cycle, the ESC module is able to perform a diagnostic test on each shock absorber solenoid, and can determine if a malfunction is present. The ESC module is only able to detect certain malfunctions during a given state (ON or OFF). In order to test for the conditions that set a DTC C1717, the ESC module must first command the RF solenoid OFF. The ESC module must be in a command OFF state. If a low voltage level is detected in the solenoid drive circuit during the OFF state, the test is again repeated. If the ESC module determines that the voltage levels detected in both tests are lower than expected, a malfunction is present and a DTC will set.

Conditions for Setting the DTC
- The ESC module detects a low voltage level (open circuit) on the RF solenoid drive circuit during two diagnostic tests performed.
- Detection for this DTC can only be accomplished when the RF solenoid is in the OFF state (0% duty cycle).

Action Taken When the DTC Sets
- Stores a DTC C1717 in the ESC memory.
- Commands 0% PWM duty cycle in order to disable the RF solenoid.
- Sends a message to the IPC to display the SERVICE RIDE CONTROL 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 a low voltage level (open circuit) on the RF solenoid drive circuit during two diagnostic tests.
- A history DTC will clear after 100 consecutive ignition cycles if the condition for the malfunction is no longer present.
- The On-Board Diagnostic (clearing DTCs) feature.
- Using a scan tool.

Diagnostic Aids
The following conditions may cause an intermittent malfunction to occur:
- An intermittent open on either of the two solenoid drive lines.
- An internal shock absorber solenoid open or high resistance.
- An intermittent open in the Real Time Dampening (RTD) relay contacts.
- If the conditions for a DTC C1717 are current the ESC module will disable RF solenoid (commanding 0% duty cycle) and the vehicle will experience a soft ride condition on the RF of the vehicle.
- If the DTC is a history DTC, the problem may be intermittent. Using a scan tool, cycle the RF shock absorber solenoid while moving the wiring and the connectors. This can often cause the malfunction to appear.

Test Description
The numbers below refer to the step numbers on the diagnostic table:
2. This step measures the resistance value of the RF shock absorber solenoid.
3. This step checks for an open in the RF shock absorber solenoid circuit.
4. This step checks for an intermittent malfunction and requests a thorough inspection of the related RF shock absorber circuit wiring and connectors.