Remote door unlock becomes unresponsive in cold weather

Are you sure that the battery inside the key fob is good? Having the remote put out a weak signal with an old battery in the cold is to be expected. Besides, it is the work of a few minutes and small change to replace the battery while troubleshooting the rest of the system will be time consuming and possibly expensive. I always try the cheap easy things first.

The car battery was changed last year, it's brand new. I've used two separate fobs, the primary and spare keys, and they both have the exact same issue.

Yousuf Khan

There is a chance both key batteries have lost charge.

Find the receiver box, and wipe it clean, maybe some junk, leaves got in the way.

Basia

Leafs. Thick ones, like Toronto maple leafs.

:)) Basia

The problem only occurs at certain temperature levels. Above a certain temperature, both keys work from several yards/metres away. Below that temperature, you have to be almost on top of the car.

Well, the engine is basically one of those sealed units, big piece of plastic on top of it, so that you can't even see much of the engine. Only have access to the battery, and fluid filler caps, and that's it. Don't know where the receiver box is, as I can't see it.

Also again, the problem is temperature related. If it was leaves and stuff, the problem would be apparent at all times, but it's not. Below 0 degrees C, the distance is reduced. I can tell this because when I have left the car inside a semi-heated garage, where the temperature goes up over 0C, and the range is good again. Take the same car just outside the garage, where it's below freezing, and the range is awful.

Yousuf Khan

I might assume the receiver is acting up when cold. Almost not tuned to right frequency, drift. Sounds rf related.

Greg

A weak battery could cause that symptom. I vote with John McGaw that the first thing you should try is a fresh battery in the fob.

Today, I started to test to see if I held the button down longer, if this would work. So far, it looks like it might be working. I'll keep conducting the test. Typically in the summer-time, I'd just give it a brief press (tenth of a second or so) and it would open up, but maybe in the winter, I'll have to adjust my timing?

Yousuf Khan

Okay, so it turned out that the batteries in both key fobs had batteries that went down at the same time.

Yousuf Khan

Glad that your problem was so easily solved.

Yeah, the coincidence of the twin failures fooled me into believing that there was something more complex going on here.

Yousuf Khan

I had a similar experience some years ago. My headlights went out so I was sure the problem was a switch or the relay but in fact both bulbs had burned out at the same time.

My remotes do it too when it gets to about 4* above freezing. New batteries have not improved it. I now have to keep my remotes covered and at a decent temperature so they keep working.