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Hi there

Apologies if this is in the wrong thread I***8217;m brand new here.

I have a 645 on a 04 plate which has serious electrical issues.

It started with a transmission malfunction warning which would go away after switching off and back on. That seemed to go away for a while then the engine management light came on and the car seemed to lose power, not full on limp mode but definitely reduced revs. Then the car started telling me all the tyres are flat which they***8217;re not then the transmission message came back and the car seems to be stuck in 5/6th gear when in drive. The lights flicker when revved and the speakers cut out.

The battery puts out 12volt when dead and 15volt at idle. I***8217;m looking towards a new battery properly programmed along with alternator and voltage regulator.

Any ideas would be appreciated as I***8217;m struggling to find anyone to look at it in the Essex area.



Thanks
 

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You should be reading just over 12 volts with the ignition on, lights on and engine off, 15v volts at idle is getting up there a bit though, should be down more around the 14.25-50 mark really.
If the battery is 4-5+ years old you might want to consider swapping it out anyway but given what I've had in the past and what your describing I'd be looking at the voltage regulator first rather than a whole new alternator and take it from there, they're cheap too.
If you do swap this out make sure you get the right one, it will either be Valeo (most likely) or Bosch, actually replacing the regulator is a breeze but it's the removal and reinstall of the alternator to do it which is the pain.

If your not taking it to a garage and doing it yourself then have a look here at the TIS for the alternator removal, patients is key to this job.
 

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Discussion Starter #3
Thanks for that. I would assume the car would need to be reprogrammed after this has been carried out?
 

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I had the same problems, I tought it was the battery but it was the regulator. Pulled the dynamo and replaced the regulator and it is solved now
Hsurf is right, most of the time the regulator is much cheaper than a new alternator. I bought my regulator for ***8364;50,- new. Part is Hitachi 130644

- starting the car and had transmission, dynamic drive, abs error
- after starting again all faults were gone
- battery was 12.3v on contact
- 15v on idle

Dynamo out are 3 bolts and also take the fan out for space. You can do it in 1 hour first time with the right tools

:thumbup:
 

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Discussion Starter #5
Sounds good I***8217;ll definitely try that. Would it be worth doing the alternator while it***8217;s out?
 

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Then again if it***8217;s only an hours work it can***8217;t hurt to try the cheapest option first. Makes sense you***8217;re right
 

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Replace the battery 1st, then go from there. There is no sense to waste money on an alternator if not needed. If you are seeing Dynamic Drive warnings after 10 to 15 minutes of driving, your regulator is bad, & can be purchased on Ebay fro around 70.00. It is ok to put OEM parts on the car, but do not use aftermarket parts that are not OEM. You should have a Valeo altenator that can be purchased on Ebay for around 300.00. Read the fine print to make sure it is new, not like new.
 

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The warnings I***8217;m getting, transmission fault, engine fault, flat tyres used to spring up a few minutes after starting now they are there constantly and can***8217;t be removed
 

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It sounds like you have a battery problem. If you can work on your car, you need to get a copy of Carly, or ISTA to solve your current & future problems. A standard OBD2 reader is not much help working on a BMW, to find & fix the problem. If your battery is not the problem, I would start looking at the IVM since it controls every sensor on the engine & transmission. A tranny problem such as low fluid, or a bad Mechatronic's Adapter Seal could have hardened & is not holding pressure in the valve body. This problem will cause a problem with the engine management, & force you to reduce speed & pull over.
 

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The warnings I'm getting, transmission fault, engine fault, flat tyres used to spring up a few minutes after starting now they are there constantly and can't be removed
I had exactly the same faults. When starting the car, the dynamo has to take over, but when it can't deliver the power, the faults come because they don't get the juice from the alternator.

After I turned the engine off and locked the car and start again after a couple minutes, the faults were gone except the flat tire fault.

If you take the alternator out, clean it and take out the regulator that is inside the alternator and replace it. Make sure to clean every thing before you put it all back.

My regulator was the problem, but this was my experience of course. If your battery is 4/5 years old, replacing it would be a good thing to do also.

Good luck:thumbup:
 

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The battery was new but I found out recently the seller replaced it and didn***8217;t program it...... I believe that causes problems? It***8217;s a cheap nasty one too so will definitely be replaced as well as long as I can suss out how to program it and find the right machine to do so
 

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The battery was new but I found out recently the seller replaced it and didn't program it...... I believe that causes problems? It's a cheap nasty one too so will definitely be replaced as well as long as I can suss out how to program it and find the right machine to do so
That could be a problem. A new battery has to be registered via obd, otherwise the IBS ( Intelligent Battery Sensor can be found on the negative cable on the battery, small block ) will think it is charging an old battery
If it is a AGM battery you need a VARTA H15 105ah ( or 95ah depends on what's coded in the car )
If it is a normal battery you need a VARTA I1 110ah

With a car like this it is good to have a laptop or something to communicate with the car.
I use a laptop with INPA and that works for the basic things like read and erase errors and also register a new battery. If you need any help with this let us know.

:thumbup:
 

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You have not said how many miles are on the car, & exactly what took place after your purchase. If you are going to purchase a new battery, go with either the Exide battery that BMW sales, or the Bosch battery that Pep Boys sales. Since you have an 2004, you have a lead cell battery, not an AGM. You can put the AGM without problems, but register the battery soon as possible. You can try & negotiate a new battery from BMW for around 200.00 to 225.00.
 

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If it's a cheap and nasty battery then that could well be part if not all of your problem (especially if it isn't registered), that said people have been known to plonk a battery in without registering and they've lasted a long time but ultimately the batteries life will be significantly reduced if not registered and your back to square one.
When I had these issues I knew my battery wasn't the problem as I'd previously replaced and registered it some time before, in this instance though yours is a bit of an unknown since it's a cheap one and I'm afraid very cheap batteries don't tend to do well in these cars.

We don't have a Pep Boys here, I guess our closest equivalent would be Halfords but I think they only now stock their own brand of batteries and I've no idea on the quality of them, you may need to order one up online if you want the cheapest price on a good one, as HerbP says, go with Exide (preferable) or Bosch for here in the UK.

When I replaced mine I upgraded to the AGM given how power hungry these cars are, it's worth the swap but the registering process is a little more in depth if making this change, have a read of this (if you haven't already) that HerbP put together, it will tell you all you need to know, I can't for the life of me remember if the Carly app is listed in there but this is by far the easiest way to make the change from lead acid to AGM if that's the way you want to go, this is what I did but I'd rather push you towards getting the BMW software if you're doing it all yourself as this will be much more useful in the future (and I believe can now be had cheaper than the Carly app and adaptor plus though not certain I think you may have to pay for "in app" purchases), the more detailed diagnostics and test plans alone are worth it.
I'd also recommend a battery tender like a Ctek if you don't do a lot of miles.
 
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