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I've noticed that every time I connect ISTA there is a message relating to 'undervoltage'....Always thought nothing of it until yesterday which is when I decided to check my water temps whilst driving home via the hidden menus etc. Basically under the voltage section it was showing 12.7/12.6V whilst driving home.

 

I'm sure I've read somewhere that it should be around 14 volts. If this is correct then am I right in saying it could be a potential alternator issue?

 

Thanks in advance.

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Above 12.0V with the engine off, ideally more like 12.7V.

 

With the engine running it depends on the ambient temperature and condition and type of battery but 14.2V to 15.0V is normal.

 

There's an alternator regulator that fails, costs around £50. What really fails is the brushes. Depending on how deep you want to go you can replace the brushes for something like £5.

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I think it will be the bushes first, I think my alternator is a valeo. anyone know a reputable place to buy from before I google...

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There's a youtube video on how to replace the brushes on a Valeo alternator. Apparently all Valeo brushes are the same and in my experience (washing machine motor) £3 brushes are just fine.

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Mine says low voltage whenever I hook it up to DIS. I'm sure I read on here that "they all do that mate!"

Mind you, a couple of times last week I got the battery light on the dash when I switched off the engine but left the key in, and it reset the clock and odometer to zero.

I was assuming the battery is on it's last legs, but I gave it a long run down the M4 and it's been fine so far this week. It does do a lot of short runs.

Perhaps it's not charging sufficiently as noted above, I will check when I get a chance.

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31 minutes ago, Phil adams said:

Mine says low voltage whenever I hook it up to DIS. I'm sure I read on here that "they all do that mate!"

Mind you, a couple of times last week I got the battery light on the dash when I switched off the engine but left the key in, and it reset the clock and odometer to zero.

I was assuming the battery is on it's last legs, but I gave it a long run down the M4 and it's been fine so far this week. It does do a lot of short runs.

Perhaps it's not charging sufficiently as noted above, I will check when I get a chance.

I ignored the ISTA message too but was convinced after seeing 12.7V via the hidden menu that all is not right.

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