For 1990-2009 cars only
Circuit Description
When the ignition switch is turned ON, the ESC module monitors communications between its internal microprocessors and performs self-diagnostic tests. If an internal malfunction is detected, the ESC module will store a DTC C0550 in its memory.
Conditions for Setting the DTC
| • | The ESC module detected an internal malfunction. |
| • | The malfunction must be detected when the ignition switch is first turned ON. |
Action Taken When the DTC Sets
| • | Stores a DTC C0550 in the ESC memory |
| • | Depending on which internal circuitry was affected by this malfunction, the ESC module will command one of the following actions: |
| - | Command 0% PWM duty cycle in order to disable all four shock absorber solenoids. |
| - | Ignore the steering position input. |
| - | Provide shock absorber solenoid control based on the vehicle speed only. |
| - | Sends a message to the IPC to display the SERVICE RIDE CONTROL message. |
| - | Sends a message to the IPC to display the SHOCKS INOPERATIVE message. |
| • | If the disable all four shock absorber solenoids action was taken, the ESC module sends a message to the PCM to limit the speed. The PCM then sends a message to the IPC to display the MAXIMUM SPEED 129 km/h (80 mph) message. |
Conditions for Clearing the DTC
| • | Under all fault conditions, the ignition must be cycled before this DTC can change from current to history. |
| • | The ESC module no longer detects any internal malfunctions when the ignition is first turned to the ON position. |
| • | A history DTC will clear after 100 consecutive ignition cycles if the condition for the malfunction is no longer present. |
| • | Use the IPC clearing DTC feature. |
| • | Using a scan tool. |
Diagnostic Aids
| • | Since DTC C0550 is an internal malfunction to the ESC module, there is no repair procedure and the ESC module must be replaced. |
| • | The ESC module tests for multiple internal malfunctions and will store a DTC C0550 if one or more internal malfunctions are detected. Therefore, depending on which malfunction was detected, and what internal circuitry was affected, this DTC may cause various symptoms. |
Test Description
The number(s) below refer to the step number(s) on the diagnostic table.
Step | Action | Value(s) | Yes | No |
|---|---|---|---|---|
1 | Did you perform the RTD Diagnostic System Check? | -- | Go to Step 2 | Go to Diagnostic System Check |
Replace the ESC module. Refer to Electronic Suspension Control Module Replacement . Did you complete the replacement? | -- | System OK | -- |
