kappers

1016<-- means loss of communication with the pcm
P1635<-- 5 volt reference circuit # 1

Where does a guy start on both of these codes?

tblu92

If the engine seems to be running fine--those are both very uncommon codes I would clear them and not worry unless they come back--

kappers

Yeah I should have posted that it will not start

luvmy98c5

Hay kappers, i'm getting the same 2 codes on my 98. Were you able to resolve your issue? After i clear my codes they come back after i drive for a little bit. I have also noticed my volt meter on the dash drops to about 11 or 12 volts when i stop the car, then goes back up to about 14. I tried swapping the alternator but that didn't help. Are you experiencing anything similar to this?

JonLT4CE

DId you ever find the P1635 code?

Thanks,
Jon

czarredd

Having this issue as well. P1635 code popped up after replacing oil pressue sensor and both 02 sensors. Was this ever figured out? Thanks

John4cam

ignition switch cleaning needed?