I have 2 remote key fobs for my Civic and neither of them work. Both of them have a good battery and the red light flashes on either button press.

Entering programming mode (By turning from I to II four times in a short period and pressing a button on the fob) works, and the locks cycle. They also cycle when I press any button on either fob briefly after entering the mode. But as soon as the key is removed from the ignition, neither of the fobs work.

I've checked replaced fuses and they seem OK, green key light appears on the dash and the beeping is heard when the ignition is turned from 0.

I was wondering if the issue could be the ignition cylinder. It is worn, and doesn't allow for the key to be pulled out at position 0. I have to very slightly turn it between 0 and I (nearly exactly between 0 and I visually) to pull out the key. I also cannot activate the steering lock by pushing in the key.

 

Check/re-check under-hood Fuse No. 9 (10A) and Fuse No. 16 (20A), which goes to the multiplex control unit that is integrated as part of the under-dash fuse/relay box.

If those fuses are okay, then it may be an issue with the wiring going to the multiplex control unit or the multiplex control unit.

 

I've re-checked the fuses and they're OK. I recently swapped fuse No. 9 due to the radio not working, the fuse had blown. I suspect it may even be draining power now, on first start today the starter felt less spry. Could this be related to the issue?

 

I would also check everything step by step in the same way! Analysis comes from simple things (their non-functionality)!

 

Have you sorted this problem?
have a civic 2011 that we have charged the entire LOCKSET with two new remote keys. Done program everything fine for one week and then suddenly the remotes, both stopped working.
it goes in program mode for remotes with ignition cycle, it acknowledge both keys turned ignition off but remotes not working. No errors or blown fuses found.
thanks