Brake lights stopped working

Hi,
About 4 weeks ago I was on 2 weeks holiday and the bike was not driven. When I started it up i got every error message possible, drive system cannot be engaged, 12v battery low, lights fault, etc.. I drove it to work and back and the messages never appeared again.

Yesterday I got a brake light fault message and my brake lights will not work. Tail lights and indicators work fine. There is no physical damage and the bike is always stored in a garage at home and in work so nobody was at it.
Any ideas? did it happen because it wasn't driven for two weeks?
Would a computer reset fix it?

Ok so 4 days without brake lights and this morning it just fixed itself.
I did not do anything, in fact I was going to work on it tonight but its working ok now. Cant explain it.
Ill reply if they break again.

Azguk said:

12v battery low

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That's probably why.
If you charged the bike since then, the internal 12V battery got charged, too.
But the battery is a consumable part, so it might work for a while, but will ultimately need to be replaced.
I'd rather do that now than later before you get stranded somewhere because it finally died.

I agree, replace it now before it dies

Would the 12v battery really die, or get so low, in just 2 weeks of not being used?
I drive it at least 4 days a week all year round.
It was fully charged before the 2 weeks parked up.
That seems pretty bad that a 12v wont last more than 2 weeks. Bike is only 4 years old.

Still, ill look into it. Like you said, better change it now that get stuck somewhere.

Azguk said:

That seems pretty bad that a 12v wont last more than 2 weeks. Bike is only 4 years old.

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Not really. It's not uncommon to have 12V batteries die after four years, that can happen. It probably should last longer in the CE04 since that kind of has a built-in battery tender, but if it has been subjected to harsh conditions, possible.
They're not that expensive anyway, but if mine dies, I'll replace it with a LiPO4 battery. Although with the built-in tender, I'd need to check if that actually works.
The battery in my GS died after about three years, replaced it with a LiPO4 and no issues since.

Edit: If I recall the manual correctly, there is an error message if the drive battery has to charge the 12V battery three times in a row, indicating the 12V is about to die. Look on page 42+ in the US manual.

Azguk: I agree with Tron. 4 years is within a median range of service life for a motorcycle battery of the size and capacity of the one used on the CE-04. It's not hard to remove the battery and properly bench test it under load to see if it's still good.

Tron: I agree with your cautionary note about checking the compatibility of the CE-04's charging system with a LiPO4 battery. The AGM 12V battery in my 2007 BMW R1200GS is 9 years old and still going. The service life surprises me. I carry a jump box with me now on that bike until I replace the battery.