DTC P1685: Invalid Skim Key: Description

Transponder ID (in ignition key) is monitored with ignition on. DTC will set in Powertrain Control Module (PCM) memory when transponder ID read by Smart Key Immobilizer Module (SKIM) does not match any transponder ID's stored in SKIM memory. Possible causes for DTC to set are: invalid SKIM KEY, defective PCM, defective connector or defective wiring.