Warning beeps but no warning light

[Webskater]

I have a 2017 Yaris Hybrid with parking sensors which have always beeped too much. But this is a different beep. When I get in the car and press the power button there is (as of today) a long loud beep, then a gap of a second or two and a single beep, another gap and two beeps, another gap and three beeps, another gap and four beeps. Then it shuts up. I drive off and when I slow down and the speed reads 8mph, it does the whole thing again. One loud, long beep, a gap, one beep, gap, two beeps etc. up to 4 beeps. If, having slowed down to 8 mph and the beeps have started, I accelerate - as soon as I am going faster than 8 mph, the racket stops. There are no warning lights. When I say ‘beep’ - it is not the horn. It is a loud warning sound but not the same as the much quieter warning you get if you have I seat belt on or a door is not closed properly. They generate a quiet, whistley sort of sound. The beep I am describing is a loud, harsh warning sound. Anybody know what could be causing this? I can’t find anything in the manual. 

[flash22]

When's the last time you change the Battery in the fob (CR2032) it's moaning as it can't find the key (smart entry and keyless go)

[Cyker]

Could it be the seatbelt warning?

[flash22]

yaris keyless go errors.pdf

[Webskater]

1 hour ago, flash22 said:

When's the last time you change the battery in the fob (CR2032) it's moaning as it can't find the key (smart entry and keyless go)

I've had the car a year - and never changed the Battery in the fob. But it is making all these beeps with both keys.

[Webskater]

1 hour ago, Cyker said:

Could it be the seatbelt warning?

No, I've tried driving it with no seatbelt on. It's a much softer beep that just repeats. The thing I am getting is one loud, long beep, a gap, one shorter beep, a gap, two shorter beeps, a gap, three shorter beeps, a gap then four beeps to finish. The whole thing takes probably 10 seconds before it shuts up. And it does it every time I slow down for any reason - and it always pitches in at 8 mph.

[Webskater]

1 hour ago, flash22 said:

yaris keyless go errors.pdf 242.58 kB · 29 downloads

Thanks for the link. It is none of those errors. It beeps once for a couple of seconds, then a gap of a count of two, then a short beep, then a gap of a count of two, then two short beeps, then the gap, then three beeps, the gap, then four beeps. It does this when I first get in the car and press the Power button and then every time I slow down and hit 8 mph - it does it again.

[Bernard Foy]

Strange one indeed.

Wonder if it’s trying to learn Morse Code🤔.

Sorry I couldn’t resist 😁

[Cyker]

Ack not good news I'm afraid - It may be your parking sensors have failed and need replacing!

Found someone reporting an identical set of symptoms:

https://www.chrforums.uk/threads/series-of-beeps.2542/

[Bernard Foy]

41 minutes ago, Cyker said:

Ack not good news I'm afraid - It may be your parking sensors have failed and need replacing!

Found someone reporting an identical set of symptoms:

https://www.chrforums.uk/threads/series-of-beeps.2542/

Looks like you’ve solved it Cyker 👏