Circuit Description
The strut actuator is controlled by the Continuously Variable Road Sensing Suspension (CVRSS) module with a Pulse-Width Modulation (PWM) signal. Switching the voltage ON and OFF at a high frequency, or pulse width modulation of 2.0 kHz, controls the amount of current delivered to the actuator. By controlling the amount of current to the actuator the CVRSS module controls the damping force in the strut. A higher level of damping force is achieved by providing correspondingly higher current levels, relating to higher percentages of PWM duty cycle. The default damper state, no battery voltage is one that provides a minimum damping force.
The CVRSS module periodically commands each strut actuator to a preset PWM duty cycle in order to override the normal PWM command. During this preset PWM duty cycle, the CVRSS module is able to perform a diagnostic test on each strut actuator to determine if a malfunction is present. The preset PWM command can be either an OFF or ON state duty cycle.
DTC C0577, C0582, C0587, or C0592
In order to test for the conditions that set DTC C0577, C0582, C0587, or C0592, the CVRSS module must first command the strut actuator OFF. If the voltage detected in the damper control circuit during the OFF state is less than a preset value, the test is repeated. If the CVRSS module again detects voltage less than the preset value, a DTC will be set.
DTC C0578, C0583, C0588, or C0593
In order to test for the conditions that set DTC C0578, C0583, C0588, or C0593, the CVRSS module must first command the strut actuator ON. If the voltage detected in the damper control circuit during the ON state is greater than a preset value, the test is repeated. If the CVRSS module again detects voltage greater than the preset value, a DTC will be set.
DTC C0579, C0584, C0589, or C0594
In order to test for the conditions that set DTC C0579, C0584, C0589, or C0594, the CVRSS module must first command the strut actuator OFF. If the voltage detected in the damper control circuit during the OFF state is between two preset values, the test is repeated. If the CVRSS module again detects voltage between two preset values, a DTC will be set.
Conditions for Running the DTC
DTC C0577, C0579, C0582, C0584, C0587, C0589, C0592, or C0594
The following conditions must be present to run the DTC:
| • | The ignition is ON. |
| • | The CVRSS module is in command OFF state. |
DTC C0578, C0583, C0588, or C0593
The following conditions must be present to run the DTC:
| • | The ignition is ON. |
| • | The CVRSS module is in command ON state. |
Conditions for Setting the DTC
DTC C0577, C0582, C0587, or C0592
The following conditions must be present to set the DTC:
| • | The CVRSS module detects voltage less than a preset value during two consecutive OFF state tests. |
| • | The fault is detected during three consecutive ignition cycles, or during the same ignition cycle after clearing the DTC with a scan tool. |
DTC C0578, C0583, C0588, or C0593
The following conditions must be present to set the DTC:
| • | The CVRSS module detects voltage greater than a preset value during two consecutive ON state tests. |
| • | The fault is detected during three consecutive ignition cycles, or during the same ignition cycle after clearing the DTC with a scan tool. |
DTC C0579, C0584, C0589, or C0594
The following conditions must be present to set the DTC:
| • | The CVRSS module detects voltage between two preset values during two consecutive OFF state tests. |
| • | The fault is detected during three consecutive ignition cycles, or during the same ignition cycle after clearing the DTC with a scan tool. |
Action Taken When the DTC Sets
DTC C0578, C0579, C0583, C0584, C0588, C0589, C0593, or C0594
The following actions will occur when a DTC is set:
| • | The SERVICE RIDE SYS message will be displayed. |
| • | ALL the strut actuators will be disabled by commanding 0 percent PWM duty cycle. |
| • | The vehicle ride will be soft. |
DTC C0577, C0582, C0587, or C0592
The following actions will occur when a DTC is set:
| • | The SERVICE RIDE SYS and VEHICLE SPEED LIMITED TO XXX km/h (XXX MPH) messages will be displayed. |
| • | ALL the strut actuators will be disabled by commanding 0 percent PWM duty cycle. |
| • | The damper relay control switch will be opened and the damper relay de-energized. |
| • | The vehicle speed will be limited. |
| • | The vehicle ride will be soft. |
Conditions for Clearing the MIL/DTC
| • | The scan tool can be used to clear the DTC. |
| • | The DTC is saved as history when the CVRSS module no longer detects the fault during two consecutive diagnostic tests. The DTC will clear if the fault does not return after 50 consecutive ignition cycles. |
Diagnostic Aids
| • | If multiple strut actuator circuit DTCs are stored along with DTC C0690, diagnose DTC C0690 first. |
| • | If the DTC is a history DTC, the fault may be intermittent. Refer to Testing for Intermittent Conditions and Poor Connections in Wiring Systems. |
Test Description
The numbers below refer to the step numbers on the diagnostic table.
-
Tests for a short or an open in the strut actuator coil.
-
Tests for voltage at the coil side of the strut actuator.
Step | Action | Value(s) | Yes | No |
|---|---|---|---|---|
Schematic Reference: Suspension Controls Schematics | ||||
1 | Did you perform the Road Sensing Suspension Diagnostic System Check? | -- | Go to Step 2 | |
Does the resistance measure within the specified value? | 9.5-15.5 ohms | Go to Step 3 | Go to Step 8 | |
Does the test lamp illuminate? | -- | Go to Step 4 | Go to Step 5 | |
4 | Test the damping servo control circuit of the strut actuator for a short to ground, a short to voltage, or an open. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 10 | Go to Step 6 |
5 | Test the damper servo supply voltage circuit of the strut actuator for a short to ground or an open. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 10 | Go to Step 7 |
6 | Inspect for poor connections at the harness connector of the strut actuator. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 10 | Go to Step 7 |
7 | Inspect for poor connections at the harness connector of the CVRSS module. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 10 | Go to Step 9 |
8 | Replace the strut/shock absorber. Refer to Strut Assembly Replacement in Front Suspension or Shock Absorber Replacement in Rear Suspension. Did you complete the replacement? | -- | Go to Step 10 | -- |
9 |
Important: Perform the set up procedure for the CVRSS module. Replace the CVRSS module. Refer to Electronic Suspension Control Module Replacement . Did you complete the replacement? | -- | Go to Step 10 | -- |
10 |
Does the DTC reset? | -- | Go to Step 2 | System OK |
