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The P1697 is pointing to a fault with the PCM (on-board computer) not being able to accept information, specifically the milage, to be programmed/written to the internal memory (aka EEPROM, think of it like a mini hard-drive inside the computer). Diagnostic of this code will require a scan-tool, but most commonly, the PCM will need to be replaced. There is a chance it can be reprogrammed/reset, but this is not always successful. With the use of a scan tool, a "manual" force write must be attempted. If it fails, the PCM will need to be replaced.