KESSY key fob low battery alert

[yeahforbes]

I noticed that when my KESSY key fob has a low battery level, a DTC gets stored in the relevant module. The message in VCDS will even tell me whether it's fob 1 or fob 2. If I happen to scan the car and see this before the fob totally dies, that's really cool because it saves me from the battery fully dying, and the subsequent hassle of having to manually unlock the car (popping off the plastic cover) and holding the fob up to the steering column during push-to-start (for short range immobilizer communication).

I find it extremely strange that the car only reports this via diagnostic scan. There is no warning on the MFD, MIB, etc at least not for my 2017 R. Of course the MFD is happy to warn me about the key being not found, though.

Curious to hear if anyone has figured out a way to have the car alert the driver without a scan tool.

 

[kevinkar]

I am convinced I remember seeing a low battery notice in my entertainment unit's screen in the past 5 years regarding the FOB battery. That being said, I have gotten into the habit of replacing it every couple years regardless of its charge state anyway just to be on the safe side.

 

[KevinC]

I change my batteries about every year and a half, but got caught recently with my pants down. I was in Vegas and headed out to the car to pick up a friend at the airport, and boom, no keyless entry of any kind. Thankfully I knew to pry off the keyhole cover and open the car with the key, which of course set off the alarm until I could get the car started by holding the fob to the steering column, but what a freaking hassle. And what about the average owner who has NO idea what to do in this situation? AAA, a locksmith, or tow truck would have to be called.

Weird that we're not getting a warning in the cluster. I know the car is capable of this.

 

[yeahforbes]

I know the car is capable of this.

Yeah I mean theoretically the MFD could alert on any DTCs, but it doesn't because so many things are intermittent and shouldn't generate concern until a shop confirms -- that makes sense to me. It's super weird that this particular DTC doesn't alert though, because the fob battery will die before the next shop visit, and shops don't scan for typical non-diagnostic maintenance, and I'm hoping to hear that the firmware to support this is already in place but the default coding suppresses it.

 

[yeahforbes]

replacing it every couple years regardless of its charge state anyway just to be on the safe side.

Not a bad idea. However, my understanding is that the battery lifecycle is highly dependent on an accelerometer: when the fob is at rest (say, laying on a surface or hanging on a hook) it draws negligible current (not transmitting), but if acceleration is detected (say, in your pocket) it draws significant current (always transmitting). So the recommended number of months/years would depend on user habits. All the more reason for the car to alert the driver when it's low.

 

[kevinkar]

Not a bad idea. However, my understanding is that the battery lifecycle is highly dependent on an accelerometer: when the fob is at rest (say, laying on a surface or hanging on a hook) it draws negligible current (not transmitting), but if acceleration is detected (say, in your pocket) it draws significant current (always transmitting). So the recommended number of months/years would depend on user habits. All the more reason for the car to alert the driver when it's low.

That's interesting and I've never head that. Every key FOB is carried in a pocket and is likely always moving so I can't see why an active accelerometer would be included in one but maybe it is. I can't imagine a driver exiting their car for a very long walk, ski day, playing in a park, etc. would require the key to transmit continually. I don't see any reason/advantage to do so other than to line the pockets of "big battery."

I thought the key would be passive until you got close to the car and pressed one of the lock/unlock buttons, grabbed the door handle or hatch release and the car transmitted with the FOB responding to the ping. It does so at rest for sure (confirmed in my garage.)

 

[yeahforbes]

Well, even if the key isn't always transmitting, it needs to be ready to receive a transmission from the car as you describe, and "ready to receive" could involve an amount of current draw that's worth avoiding when the fob is completely stationary, since there's no practical scenario where the car needs to transmit (based on a person touching the exterior door handle) to a stationary key. I suspect that your garage test involved the key not being stationary quite long enough to fall asleep?

https://www.enyaqforums.co.uk/viewtopic.php?p=5723#p5723 says:

the KESSY system ... keyfobs have accelerometers in them, so if they're not in motion (ie in a pocket or hand) they will not transmit anything. So if they're sitting on a table for more than a couple of minutes they're effectively just a dead lump of plastic as far as signals are concerned.

 

[amsr]

I got a notification in the infotainment when mine was about to die a couple weeks ago. I have a 2017 GTI SE. The fob batteries seem to last about a year. They are CR2025 but you can get a 2032 in there - caveat being the little rubber gasket won't seal as well with the bigger battery so it won't be water tight.

 

[yeahforbes]

I got a notification in the infotainment when mine was about to die a couple weeks ago. I have a 2017 GTI SE.

Interesting! What infotainment unit do you have, and do you happen to have obdeleven or VCDS to share coding/adaptation info?

 

[amsr]

Interesting! What infotainment unit do you have, and do you happen to have obdeleven or VCDS to share coding/adaptation info?

I think it’s an MIB II and I don’t have a way to check the coding. It’s stock though.