Circuit Description
The radio (IRC) calibrations are stored in the electronically erasable programmable read only memory (EEPROM). When the ignition is turned ON, the radio performs internal tests on the EEPROM. The tests determine the integrity of the non-volatile memory.
Conditions for Setting the DTC
When the ignition is ON, the radio performs internal tests on the EEPROM. The test determines the integrity of the non-volatile memory. The radio compares the previously stored checksum with the checksum calculated when the ignition turns ON. If the 2 checksums do not match, the radio sets DTC B1658 as current.
Action Taken When the DTC Sets
The radio performs the following functions:
| • | Clears all other stored DTCs. |
| • | Logs DTC B1658 as current. |
Conditions for Clearing the DTC
| • | When the ignition switch cycles from OFF to ON and the checksum read by the radio matches the previously stored one, DTC B1658 changes to a history DTC. |
| • | A history DTC clears after 50 consecutive ignition cycles if the condition for the malfunction is no longer present. |
Diagnostic Aids
If DTC B1658 is set, clear the DTCs and cycle the ignition. If DTC B1658 is still current, replace the radio.
