Service Information

Volt

DTC C0550

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 C0550 00: Electronic Control Unit

DTC C0550 35: Electronic Control Unit ROM Malfunction

DTC C0550 39: Electronic Control Unit Internal Malfunction

DTC C0550 43: Electronic Control Unit EEPROM Incorrect Programming

Circuit/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 B1325, B1330, B1370, B1380, B1424, B1440, B1441, B1517, C0800, C0899, C12E1, P0560, or P0562 is not set.

⇒	If any of the DTCs are set, refer to Diagnostic Trouble Code (DTC) List - Vehicle .

Verify that DTC C0550 is not set.

⇒	If the DTC is set with symptom byte 39 or 43, program the control module that set the DTC. If the DTC resets, replace the control module that set the DTC.

⇒	If the DTC is set with other symptom bytes, replace the control 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