Diagnostic Aids

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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 125A MEGA fuse can result in an erroneous DTC C0550.

Fig 1: DTC C0550 (Step 1-5)
Courtesy of GENERAL MOTORS CORP.

Fig 2: DTC C0550 (Step 6-11)
Courtesy of GENERAL MOTORS CORP.