For 1990-2009 cars only
Diagnostic Instructions
| • | Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure. |
| • | Review Strategy Based Diagnosis for an overview of the diagnostic approach. |
| • | Diagnostic Procedure Instructions provides an overview of each diagnostic category. |
DTC Descriptors
DTC C0550 XX: Electronic Control UnitCircuit/System Description
The internal fault detection is handled inside the control module. The symptom byte listed in the DTC Descriptor is for engineering reference only. No external circuit diagnosis is involved.
Conditions for Running the DTC
The module runs the program to detect an internal fault when power up is commanded. The only requirements are voltage and ground. This program runs even if the voltage is out of the valid operating range.
Conditions for Setting the DTC
The module has detected an internal malfunction.
Action Taken When the DTC Sets
The module refuses all additional inputs.
Conditions for Clearing the DTC
| • | A current DTC clears when the malfunction is no longer present. |
| • | A history DTC clears when the module ignition cycle counter reaches the reset threshold of 50, without a repeat of the malfunction. |
Diagnostic Aids
| • | This DTC may be stored as a history DTC without affecting the operation of the module. |
| • | If stored only as a history DTC and not retrieved as a current DTC, do not replace the module. |
| • | If this DTC is retrieved as both a current and history DTC, replace the module that set the DTC. |
Circuit/System Verification
Verify that DTC C0550 is not set.
| ⇒ | If the DTC is set, replace the module that set the DTC. |
Repair Instructions
Perform the Diagnostic Repair Verification after completing the repair.
Control Module References for module replacement, setup, and programming
