Circuit Description
The EEPROM check sum error detection is handled inside the control module. No external circuits are involved.
Conditions for Running the DTC
The microprocessor runs the program in order to detect a check sum error after each "power up". The only requirements are voltage and ground. This program runs even if the voltage is out of the valid operating range.
Action Taken When the DTC Sets
The microprocessor reverts to base operation values programed for those blocks of data that have failed the check sum test. The blocks of data that have not failed the check sum test are not affected.
Conditions for Clearing the MIL/DTC
The DTC clears when the microprocessor runs a successful check sum test of the EEPROM.
Diagnostic Aids
Important: The DIM must be replaced if the DTC is retrieved as a current or a history DTC.
| • | This DTC may be stored as a history DTC with out 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. |
Step | Action | Value(s) | Yes | No |
|---|---|---|---|---|
1 | Did you perform the Diagnostic System Check? | -- | Go to Step 2 | |
2 | Replace the module. Refer to OnStar Vehicle Interface Unit Replacement . Did you complete the replacement? | -- | System OK | -- |
