That 2012 Hyundai push button smart key: add key/no start turned into a fun one, started as a no crank no start, key fob inop, when the key was inserted into the fob holder in the armrest it wouldnt recognize it. No key message on dash even with key in fob holder. Replaced fob battery car now fob works, cranks but does not start, when key is OUT of fob holder, Fob inserted “no key” message on dash.
PCM has P1696 Immobilizer code not received. Removed key holder and found corrosion and broken/missing circuit board components. Sunroof leak. Replace keyholder, now crank no start with fob in holder. Able to program keys, but Code P1696 persists. Neutralized modules and relearned keys. Same result.
Tested circuit from Smart Key Module to PCM all good, got a good used pcm and SKM from recycler, pulled Security PIN from originals, installed both recycles, pulled pin number from those, installed orginal pcm and neutralized SKM with recycled pin, neutralized the original PCM, programmed key, code P1696 persists in pcm, crank no start. Replace PCM with recycle, use recycle pin to neutralize, install orginal SKM, neutralize with original pin, program keys. car starts. no codes. yay. Diagnosis: Dead key battery, water damaged key holder, PCM internal failure. It took three 2 hour sessions including self education for my first time in this system.