Problem: Key fob and dashboard trunk button intermittently don't work
 

My 2014 FR-S has started having an odd problem - can anyone offer advice?

The electronics that unlock the doors and open the trunk are intermittently not working.
At first I thought it was a dying battery in the key fob, but the dashboard button to open the trunk also did not work at the same time the car wouldn't respond to the fob.

The trunk button and the fob started working again after I put the key in the ignition and turned it to the on position.

It doesn't happen every day. I think in the past two weeks it has happened twice, maybe three times.

is it consistent that when it doesn't work, both refuse to work during that time?

try checking fuses first, as turning the car on enables other electrical circuits to turn on which could be bypassing a problem fuse.

just be sure to check that nothing's resting against the valet button in the trunk-- i believe that would disable both remote buttons.

otherwise, it could be the trunk solenoid starting to fail, which isn't too hard to change.

Sounds silly, but have you changed the keyfob battery? When it gets low, around 3.05 or below it can act strange.

It's easy enough to engage/disengage the valet button in the trunk several times to make sure age/corrosion/dirt haven't come into play as it mostly goes unused (except when inadvertently pressed by shifting cargo!).

Had the same issue when I first got my car, ended up just being the Keyfob needing a new battery.

Based on both the fob and the dashboard trunk button failing (if it were the fob battery, the dashboard trunk button would be unaffected), and the intermittent nature of the problem, my brother (former auto mechanic) suspects the problem is in the electronics that handle the electric door locks and the electric trunk release.

His theory is that solder traces/joints in the electronics are developing cracks.

The car is 7 years old, daily driver. Things break over time.

To be continued...

@Muckraker
Are there any other strong signals close by that are transmitting, and possibly interfering with your keyless operation? For example: Are you only having this issue in one area, or does it also happen when you.....say.....make a run to the grocery store or to fuel up or.....?

Is there anything inside your vehicle that is transmitting a signal that you can remove or power down temporarily to test this theory?

You didn't answer the question. Have you at least tried replacing the fob battery? You could have two separate issues going on and for a couple of dollars you could eliminate the possibility of one.

considering that it seems that your problem is somewhat a lone duckling, being that very few others are complaining about similar issues, i would say that while cracked or damaged circuit boards are possible, it's quite a distant possibility. damaged circuit boards generally have external factors involved in the damage. generally, i've only seen it on 15+ year old vehicles, and usually in cases where the circuit boards are improperly mounted, exposed to the elements, or subject to extreme heat cycling. none of which should really be the case in these cars.

is this mostly happening at your home? check if led light bulbs are on. many cheaper models emit enough EMI to mess up the thought process of passing geese flocks...

The first thing I would look into is if the valet button is being bumped by something in the trunk.

The second thing would be batteries.

And the third would be the trunk popping solenoid