Facelift Cruise Control not working after changing key batteries

[jason15300]

Hi All,

I understand there are countless topics on this however most cruise control topics are regarding ACC, my Audi A3 only has the basic cruise control with no radar unit.

A bit of background info:

This morning (around 10:00) my key fob were showing low battery, I had popped to the shops and I thought I'd just replace the key with the spare, when I got home and did this, the same issue was present on the spare. I had bought my Audi from Audi Used Approved in August 2020, maybe the battery replacement was long due. At this point, this cruise control was working as normal with no errors.

I had some unopened CR2032 batteries, I followed a guide and replaced the batteries. I then checked both key fobs could remotely lock/unlock the car, which was met successfully.

Issue:

I wanted to check the key had no issues with starting the car, so I popped my first key into the ignition. Instantly, the cruise control unavailable error came up. I referenced it in the guide which didn't give me any helpful fixes. I tried the second key thinking it might be a key security issue, this time a handful of errors came up ranging from tyre pressure to auto stop-start. I turned the car off, took the key out of the ignition, waited a few minutes then repeated the process, the errors except for the cruise control disappeared and thankfully hasn't come back since.

What could have caused this issue? I am sure it can't be a wiring or fuse issue as I literally drove the car a few hours ago and no issues were present? This only popped up after I changed the key fob battery. I am thinking of taking the car down the nearest dual carriageway and trying to see if the cruise control will engage. I don't know if the basic cruise control disables at certain temperatures? I have used my car a handful of times in the past 20 days so it hasn't been sitting idle in the cold. Alternatively, I still have the old batteries, I might swap out the battery on the spare key and see if it is resolved.


Any ideas or feedback?


Many Thanks,

Jason

Side note: At the time of writing this, it is around 1 degree celsius outside.

 

[jrumball]

Are you sure the Battery Low was the key fob and not the 12v battery, it's the classic time of year for an old 12v battery to go low and cause all sorts of electrical gremlins ....

 

[jrumball]

Are you sure the Battery Low was the key fob and not the 12v battery, it's the classic time of year for an old 12v battery to go low and cause all sorts of electrical gremlins ....

 

[jrumball]

Are you sure the Battery Low was the key fob and not the 12v battery, it's the classic time of year for an old 12v battery to go low and cause all sorts of electrical gremlins ....

 

[jason15300]

Update:

I changed the spare key to the old battery and no issues were present, again this was really weird. I then grabbed my main key with the new battery. No issues present. Maybe the A3 glitched out at that certain moment? It also take a few seconds to start up but then again it is quite cold, might look into the car battery health. Will update this thread if the cruise control decides to play dumb again.

 

[jason15300]

Are you sure the Battery Low was the key fob and not the 12v battery, it's the classic time of year for an old 12v battery to go low and cause all sorts of electrical gremlins ....

Yep it was for the key fob, i got the battery low on key error. I think this whole issue was some weird glitch, I will do some testing over the weekend

 

[NHN]

Sometimes after battery changes it takes a few cycles to recognise, dont worry to much.