I have got the p1633 code pooping up in my trac since around July. it causes no known problems to the vehicle, just the CEL. when cleared, the code comes back immedietly. since I have gotten the code I have :tested battery (good), replaced battery terminals, tested and replaced an alternator with a bad voltage regulator , and have checked as many body grounds as I can find. is the PCM toast? or is a harness wire broken somewhere? please help if possible Aaron
NO IDEA what p1633 is, but saw this EF post and thought it may be worth one minute to try. Good luck. http://www.explorerforum.com/forums/index.php?threads/2nd-gen-issues-try-this-first.464701/
Code p 1633 After a long stretch of internet searching I started with the battery terminals because they were corroded so i fixed that problem. Then before I did anything else I cleared the code p 1633 again and it popped right up again. So I have a friend who has All data on his computer and had him print me out a copy of the fuse box so that I could tell what fuse is what and if a fuse even belongs there given that there is so many spaces open in the fuse block. And when I compaired the copy I had to what was there I noticed that there was a fuse missing in one spot and another fuse where there should not have been one just 2 spaces away I looked up what those spaces went too and yep there it was it went to PCM so I put the fuse where it belonged and it cleared instantly.
P1633 - Keep Alive Power Voltage Too Low Indicates that the Keep Alive Power (KAPWR) circuit has experienced a power interrupt. Open KAPWR circuit Intermittent KAPWR Damaged PCM Loss of KAPWR to the PCM will result in a immediate MIL illumination and a DTC P1633.
