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 00: EEPROM Checksum MismatchDTC C0550 39: EEPROM Checksum Mismatch
Circuit/System Description
When the ignition is turned ON, the microprocessor runs a diagnostic program to detect an internal fault when power up is commanded. If an internal malfunction is detected, the control module will store a DTC C0550 in its memory.
Conditions for Running the DTC
The microprocessor runs a diagnostic program to detect an internal fault when power up is commanded. The only requirements are voltage and ground.
Conditions for Setting the DTC
| • | The control module detects an internal write malfunction. |
| • | The control module detects an internal checksum malfunction. |
Action Taken When the DTC Sets
If equipped, the following module specific actions may occur:
| • | The antilock brake system (ABS) indicator turns ON. |
| • | The BRAKE warning indicator turns ON. |
| • | The electronic brake control module (EBCM) disables the ABS/dynamic rear proportion (DRP)/traction control system (TCS). |
| • | The driver information center (DIC) displays the power steering warning message No Steering Assist. |
| • | The TCS indicator turns ON. |
Conditions for Clearing the DTC
| • | A current DTC clears when the malfunction is no longer present. |
| • | A history DTC clears when the control module ignition cycle counter reaches the reset threshold, without a repeat of the malfunction. |
Reference Information
Schematic Reference
Connector End View Reference
Description and Operation
Data Link Communications Description and Operation
Electrical Information Reference
Scan Tool References
Control Module References for Scan Tool Information
Circuit/System Verification
Verify that DTC C0550 is not set.
| ⇒ | If the DTC is set, perform the learn procedure on the control module. If the DTC resets, replace the applicable control module. |
Repair Instructions
Perform the Diagnostic Repair Verification after completing the diagnostic procedure.
Control Module References for control module replacement, setup, and programming
