Intermittent problem with car key remote fob

August 18, 2020 2:42 PM

My car key fob intermittently fails in a peculiar way. Details inside.

- The fob completely fails to lock or unlock the car only when parked in the driveway at home. It works perfectly well, even at a distance, everywhere else. If I get in the car after it has failed and drive 5 minutes to another location, it will then work perfectly.

- This only happens some of the time, but when it happens it fails completely. No matter how close I get to the car, even touching the key to the window, it doesn't work.

- Only this fob doesn't work; another fob in the household that is equally old and has been used roughly the same amount of times if not more, works just fine when mine fails.

For these reasons, I don't think it's battery related (because it works just fine minutes after failing) and I don't think it's some kind of interference (because the other fob works just fine).

Any ideas? This isn't a huge deal, but it's annoying when it happens and means that I sometimes needlessly set off the car alarm when opening the door with the physical key. Car is a Subaru Crosstrek.

posted by googly to Travel & Transportation (11 answers total)

Have you tried resetting the key? With most cars you can do this via the ignition - there's usually some 'secret' pattern of turning the car on and off a number of times, or for a certain number of seconds. Details should be in your manual, or online.
posted by pipeski at 3:00 PM on August 18, 2020

Honestly I would change the battery just to eliminate that possibility.

Any chance it could be water damage?
posted by danceswithlight at 3:04 PM on August 18, 2020 [4 favorites]

This happened for a whole southern NZ town recently when council licensed part of radio spectrum used by car locks. Sounds may be the same on your very local scale.

What's transmitting nearby?
posted by unearthed at 3:04 PM on August 18, 2020 [1 favorite]

- Only this fob doesn't work; another fob in the household that is equally old and has been used roughly the same amount of times if not more, works just fine when mine fails.

I mean, it's very likely this is the battery. You could switch the batteries between fobs to prove it.
posted by bbqturtle at 3:05 PM on August 18, 2020 [3 favorites]

This is pretty much how my fob stops working when the battery is dying. It's not really an expensive fix. (Other trick is to hold the fob to your chin, increasing the range.)
posted by jeather at 4:45 PM on August 18, 2020

I wouldn’t rule out interference. They don’t all use the same frequency.
posted by Automocar at 5:03 PM on August 18, 2020

Hah. One of mine for my civic only works when the ambient temperature is above 70-ish degrees F. And then only sometimes. I've replaced batteries, cleaned button pad contacts, etc and still can't get it to work consistently.
posted by ArgentCorvid at 5:36 PM on August 18, 2020

Google "key fob rfi interference" (which is redundant, but helps the search) and you'll find all sorts of bizarre stories about random electronic gear clobbering the spectrum the fobs use.
posted by dws at 9:52 PM on August 18, 2020 [1 favorite]

I had very similar to this issue with my fob, changing the battery out seems to have cleared the issue.
posted by rudd135 at 4:07 AM on August 19, 2020

I haven't dealt with the Subaru fobs, but I just got a Volvo with worn out old fobs. I got a new case for one of them (new plastic, buttons, one battery contact). After I moved the electronics over, it works great with the same battery it barely worked at all with.
posted by wotsac at 6:12 AM on August 19, 2020

Response by poster: unearthed: I am in a residential neighborhood so nothing transmitting super-close. But I do live about 3km away from a large TV/radio tower.
posted by googly at 9:32 AM on August 19, 2020