Recently we had the red battery (alternator) light coming on - firstly just for a while then went off, now all the time. Recently the car has mainly been used for short nursery runs so I thought it might be the battery and it might sort itself out after a good run. Anyway then the airbag, power steering and ABS shutdown so the battery voltage must have dipped and I see the light means the alternator is not charging. I've taken it to my local independent and with the engine running it was only about 11.9V across the battery so apparently it's not charging properly and we need to replace the alternator.

 

Is this unusual as IIRC I've not had an alternator fail before - certainly not on a car this new (Apr 09 & 49k on the clock)? Is there anything else that could be wrong? (even reconditioned alternators aren't exactly cheap...)

 

TIA!

 

Simon

Unless the battery is goosed then yes, sometimes they just "fail"..

Not unusual at that mileage and age but not a Fabia weakness in the same way Ford Focus was. Seems you were just unlucky.But as said check it's not the battery as you are bang on the battery life mileage/age there.

Edited 11 October, 201312 yr by horkin

Did they test the battery too?

If you had one bad cell, that's the voltage I would expect.

Have you tried charging the battery. When the battery is fully charged, what voltage do you see with\without the engine running

Did they test the battery too?

If you had one bad cell, that's the voltage I would expect.

Have you tried charging the battery. When the battery is fully charged, what voltage do you see with\without the engine running

Thanks everyone! No they didn't check the battery - just the voltage with the engine running.

 

I did charge the battery as it was the first thing I thought was wrong - only for a few hours and I think it got to 13V+ though maybe not 13.8V. Perhaps I'd better full charge/check that again first as I was expecting to replace that sometime fairly soon anyway given the short runs the car gets. I'll post an update tomorrow.

Edited 11 October, 201312 yr by Simon300

I would check wiring/fuse failure first. Check output voltage directly at alternator. Then check the main HD fuses which I think are probably under that cover on the battery terminals.

 

It is very unusual for an alternator failure at that mileage/age. Most alternator failures are due to worn slipring bushes normally at least 150,000+ miles - and you usually get intermittent problems before total failure.

 

Battery charging voltage (alternator or an external charger) should be 14.3 volts or more. So if it is struggling to get abouve 13 volts then your battery is probably goosed with a duff cell.

Edited 11 October, 201312 yr by xman

I would check wiring/fuse failure first. Check output voltage directly at alternator. Then check the main HD fuses which I think are probably under that cover on the battery terminals.

 

It is very unusual for an alternator failure at that mileage/age. Most alternator failures are due to worn slipring bushes normally at least 150,000+ miles - and you usually get intermittent problems before total failure.

 

Battery charging voltage (alternator or an external charger) should be 14.3 volts or more. So if it is struggling to get abouve 13 volts then your battery is probably goosed with a duff cell.

 

Thanks xman. I suppose I did get an intermittent warning - the red light was on once or twice a few weeks ago but went off (I wasn't driving so I don't know if it was mid-journey or between starts), but is now on all the time.

 

Hmmm - I've just measured 14.3V at the battery (which a cheap digital multimeter)! So it was 11.something, say 12V, at the local garage with the engine running but a short trip home (5-10 mins max), then sitting on the drive and a day later it's 14.3. Sounds odd.

 

None of the fuses under the cover on the battery have blown. I've put my CTEK electronic battery charger on it anyway for good measure (its indicator suggest it's got a bit more charging to do).

14.3 is bang on. Check all the wiring back to the alternator, particularly connectors for intermittent connection or damage.

 

I've just noticed yours is a Greenline - I dont know if yours is fitted with the energy recovery system (as the latest models) - I think this uses an oversized "smart" alternator and an expensive AGM battery along with dedicated charge/recovery electronics (might be part of the ECU) - that would make it quite difficult to find the fault as the alternator output varies - it could be the charge/recovery system is playing up.

No it's not got the energy recovery system - I've just had a look and I think mine's the Greenline (I) 109g version not the newer Greenline II 89g version.

 

I've just measured:

• 15.5V whilst the CTEK was charging it
• When I disconnected the charger it was about 15.5V but falling a little
• I started the car and it was reading 14.9V on the battery and almost the same at the alternator (quite hard to get a good contact with the ground & alternator teminal so varied a little as I scratched the probe around)
• After stopping the engine the reading from the battery is not very stable - started at about 14.9V and went to around 15.8V (I don't know if this is my meter or the battery recovering from starting the engine).

The red alternator warning light is still on. It's been starting fine - the only problem was the other day when the voltage must have fallen to shut down the power steering etc. So there must be some sort of fault. Any idea how the ECU knows to put the alternator warning light? It can't be just voltage at the battery as that's OK.

Does the Mk2 Fabia suffer from the same issue with the broken alternator signal wire?

 

Sounds quite similar.

 

Phil

Thanks Phil-E.

 

I had a read about the broken alternator cables (e.g. http://www.seatcupra.net/forums/showthread.php?t=209472) but think my problem might be other other way round, i.e. the alternator light is on all the time not off all the time.

 

Anyway, I've tried measuring a few voltages to see if that gives any clues. The battery is currently 13.8-14.4V - my multi-meter seems to vary a bit - perhaps it needs a new battery.

 

I disconnected the 2 pin connector off the top of the alternator.

 

Plug connected to loom:

Brown/red 0.07V (ignition off), 15.xV (ignition on)

Blue 0V (ignition off), 15.1V (ignition on)

 

The pins in the alternator socket are both at 0V (ignition on or off)

 

Whilst the plug was disconnected with the ignition (engine not running) on there was no alternator light; when I plugged it back in the light was on all the time.

 

Maybe it shows the leads aren't broken but not whether the alternator is?

Probably voltage regulator in alternator kaput. You can change the alternator but a cheaper alternative is to replace just the regulator.

 

Thanks again xman   I've had a look at that video and that is exactly the same alternator design (Bosch D-connector L DFM) as mine.

 

So, my first question is - is there any way to test/be sure the regulator has failed, or is it just most likely to be that on a relatively new car?

 

Secondly, part numbers... my alternator says "045 903 020" and "14V 90A BPN 35/08" so seems 90A is the (edited:) rating. On the regulator itself it has part number "F00M 145 876".

 

I've found a regulator on Ebay made by "Topran" and with VW part number "038903803E / 109917" which looks like it might be suitable and <£20. Or else there's what looks like a Bosch original, with the exact 145 876 part number here at £50. Up to now I've used genuine Skoda parts, though the independent was recommending a reconditioned alternator so that wouldn't have been.

 

It seems to be a repair within my capabilities (alternator doesn't need removing) - at £20 it's well worth a punt, £50 less so without being confident it definitely it the regulator. What do others think - anyone done it themselves?

Edited 12 October, 201312 yr by Simon300

Does the Mk2 Fabia suffer from the same issue with the broken alternator signal wire?

 

Sounds quite similar.

 

Phil

If that breaks normally the battery light doesn't come on at all.

If that breaks normally the battery light doesn't come on at all.

 

Ah yeah. True 'dat!

 

Never mind then.

 

Phil

Thanks again xman   I've had a look at that video and that is exactly the same alternator design (Bosch D-connector L DFM) as mine.

 

So, my first question is - is there any way to test/be sure the regulator has failed, or is it just most likely to be that on a relatively new car?

 

Secondly, part numbers... my alternator says "045 903 020" and "14V 90A BPN 35/08" so seems 90A is the (edited:) rating. On the regulator itself it has part number "F00M 145 876".

 

I've found a regulator on Ebay made by "Topran" and with VW part number "038903803E / 109917" which looks like it might be suitable and <£20. Or else there's what looks like a Bosch original, with the exact 145 876 part number here at £50. Up to now I've used genuine Skoda parts, though the independent was recommending a reconditioned alternator so that wouldn't have been.

 

It seems to be a repair within my capabilities (alternator doesn't need removing) - at £20 it's well worth a punt, £50 less so without being confident it definitely it the regulator. What do others think - anyone done it themselves?

 

I've fixed a couple of alternators in the past - only thing that can really go wrong with an alternator electrically is the main diode pack - I've never seen that since the days of dodgy Lucas alternators,  worn brushes /sliprings - due to high mileage, or duff regulator (which contains the brushes anyway)

 

I would give the ebay supplier an email with your alternator numbers to check compatibility and DO REMEMBER TO DISCONNECT THE BATTERY before attempting repair - the alternator is connected directly to the battery and it would be disastrous if the wiring shorted to chassis!

Just to wrap this thread up... I ended up buying the Bosch original part for just under £50 delivered. I'm guessing the alternate brand one would have worked but the car's still pretty new so I'm sticking to original parts for now. This actually came from Germany - I spoke with them (to check the validity for my car as it was younger than those listed - perhaps it was sitting in a warehouse for a few months) and they were very helpful. I ordered it last Friday and it arrived today, 6 calendar days later. The new part actually had "F 00M A45 303" on it but looked identical to the old one. Note: a local Skoda dealer quoted me £61 for the part but unfortunately took a few days to get back to me, by which time I'd already ordered it.

Fitting was pretty straightforward - remove the covers, disconnect the battery, remove the cap on the +ve bolt on the alternator with a small screwdriver, remove the screws, bolts and covers (as per the video). Swap the regulator and follow the reverse. I'd say my brushes had worn down about 1/4, which given that I've done 50k would suggest that it might have failed at 150k+ anyway as someone suggested).

xman's suggestion to disconnect the battery is very sensible - the video suggests taping up the lead but I reckon it would have been very easy to create a short when using the spanner etc & not worth the worry.

The other thing I noticed were that, once the cover and regulator were removed, the studs were loose - I assume they are just connected to fly-leads behind but wasn't comfortable tightening them too much. Probably best not to over-tighten anyway.

Overall it took me a little over an hour to fit the regulator, using torchlight and probably wasting 10 mins trying to get the plastic engine covers back on (the little fastening grommits mostly seemed to be damaged/missing - presumably from mechanic abuse!). Oh, and 10 mins looking through the docs for the radio code only to find if you turn the ignition on it sets it automatically!

Anyway, the alternator light went out when the engine started so it appears it was the regulator. Thanks again to everyone who commented, and in particular to xman

Great result and lighter on the pocket

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