Circuit Description
When the ignition switch is turned ON, the rear wheel steering control module monitors communications between its internal microprocessors and performs self-diagnostic tests. If an internal malfunction is detected, the rear wheel steering control module will store a DTC C0550 in its memory.
DTC Descriptor
This diagnostic procedure supports the following DTC:
DTC C0550 Electronic Control Unit (ECU) Performance
Conditions for Running the DTC
Turn the ignition switch to the ON position, with engine ON.
Conditions for Setting the DTC
| • | The rear wheel steering control module detected an internal malfunction. |
| • | The malfunction must be detected when the ignition switch is first turned ON. |
Action Taken When the DTC Sets
| • | The Service 4 Wheel Steer indicator in instrument panel cluster (IPC) will be displayed. |
| • | The code is displayed on scan the tool as DTC C0550. |
| • | The output command to the motor is zeroed. The motor drive circuits are disabled using commands from the rear wheel steering control module to open the power relay. |
| • | The rear wheels will be returned to the default centered position. |
Conditions for Clearing the DTC
| • | Conditions for the DTC are not currently present. |
| • | The module receives a clear code command from the scan tool. |
| • | The DTC clears after 100 malfunction free ignition cycles. |
Diagnostic Aids
| • | Any additional codes displayed with DTC C0550 should be diagnosed and repaired first. |
| • | The rear wheel steering control 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. |
| • | Any condition resulting in the sensor supply voltage being pulled high or low could result in an erroneous DTC C0550. |
| • | A fault in the battery positive voltage circuit from the 125 amp MEGA fuse can result in an erroneous DTC C0550. |
Step | Action | Values | Yes | No |
|---|---|---|---|---|
Schematic Reference: Rear Wheel Steering Schematics Connector End View Reference: Rear Wheel Steering Connector End Views | ||||
1 | Did you perform the Diagnostic System Check - Vehicle? | -- | Go to Step 2 | Go to Diagnostic System Check - Vehicle in Vehicle DTC Information |
2 |
Are there any additional codes displayed along with the DTC C0550? | -- | Go to Diagnostic Trouble Code (DTC) List - Vehicle in Vehicle DTC Information | Go to Step 3 |
3 | With the scan tool, monitor the DTC information of the Rear Wheel Steering Control module. Does the information indicate that the DTC C0550 is current? | -- | Go to Step 4 | Go to Diagnostic Aids |
4 | With the scan tool, observe the sensor supply voltage in the rear wheel steering data. Is the voltage above the specified value? | 5.0 V | Go to Step 7 | Go to Step 5 |
5 | With the scan tool, observe the sensor supply voltage in the rear wheel steering data. Is the voltage below the specified value? | 0.25 V | Go to Step 8 | Go to Step 6 |
6 | Test for an open or short to ground in the battery voltage supply circuit of the 125 amp MEGA fuse. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 11 | Go to Step 9 |
7 | Test the 5-volt reference circuit for a short to battery voltage. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 11 | Go to Step 9 |
8 | Test the 5-volt reference circuit for a short to ground. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 11 | Go to Step 9 |
9 | Inspect for poor connections at the rear wheel steering control 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 11 | Go to Step 10 |
10 | Replace the rear wheel steering control module. Refer to Control Module References in Computer/Integrating Systems for replacement, setup, and programming. Did you complete the replacement? | -- | Go to Step 11 | -- |
11 |
Does DTC C0550 reset? | -- | Go to Step 2 | System OK |
