S60 battery light

[andymull83]

Hi,

I have just bought my mrs a 2003 S60 2.0t and she loves it. Drove it 90 miles home and no problems. After a couple of days while driving the car cut out and the dash lit up like a christmas tree! Srs, brake failure and battery light.
Having tralled google the mpst popular faults were low voltage issue caused by alternator faulty or battery.
I then checked battery to find some crappy little 44ah battery. I have now replaced the battery for a 75ah battery and roadtested. The car drives sweet but the battery light has stayed on. Any one any ideas whether its a code reset issue or a further fault.
p.s i followed the instructions for replacing the battery ie negative off first etc.
Thanks in advance!

[oragex]

that's maybe why the previous owner sold the car. Hopefully you will be able to sort it quickly.

Only a battery light would indicate the alternator, of which pulley is know to fail and can be replaced for not much (if that's the actual issue). you can try to reset it first, see if it comes back, by removing both battery poles for about 12h. if the alternator is in cause it's good to fix it quickly as it will ruin the new battery in short time.

However, the Christmas tree itself can be caused by an array of things on this vehicle, which sometimes can be difficult to isolate. Sometimes is an issue with the CEM module situated under the dash that gets water leaking from a sunroof draining pipe. In all cases, something is going wrong and this affects the main computer communication with various other modules.

[cheshired5]

Simple tests first.
Run a multimeter across the battery and check voltage levels before and during cranking, then whilst the engine is running.
Then post your results.

[reggit]

I'd guess alternator, but I also thought that would give a 'power system service required' message on the left hand display on the dash - the bit that says 'door open' etc.

[andymull83]

Thanks for the replies. I will get some further testing in and post results.

I did not expect the dreaded CEM to appear in one of the replies!!

I don't understand how it went from fine to all the warning lights and cutting out if the alternator is faulty. Would the light not come on for at least a short period before the light show on my dashboard!!

P.S mental note: Dont buy off ebay without looking first............

Thanks for the help though, hopefully i will get it sorted soon!

[cheshired5]

Originally Posted by andymull83

I don't understand how it went from fine to all the warning lights and cutting out if the alternator is faulty. Would the light not come on for at least a short period before the light show on my dashboard!

If the alternator isn't charging the battery, you have a low power state.
Volvos do strange things with poorly charged batteries.

[blueacid]

Originally Posted by cheshired5

If the alternator isn't charging the battery, you have a low power state.
Volvos do strange things with poorly charged batteries.

To expand on this, quite often the battery warning light will recognise only that the alternator coils haven't energised. Quite often they don't notice that (say) the drive belt has slipped off or similar. So the alternator can fail and the driver is none the wiser. At this point the car is running entirely off the battery. The first sign of trouble is when the more complicated computers start to struggle to stay running due to the low voltage: ABS or Airbag warning lights (or the dashboard itself going nuts).

Agree with the other poster that advised you get a multimeter and measure the voltage across the battery terminals. After sitting idle for a while, a fully charged battery should show 12.6v, empty 12.1v. Mine shows 12.2 after a long drive so I know the battery isn't really that long for this world.

When the engine is running the voltage should be higher: just over 14v or so. If it's lower than around 13.5v without you being able to explain it (heated seats, heated rear window with engine idling for instance) then that points to a charging system problem - time to investigate that alternator.

[andymull83]

Thanks for all the help and advice. I didnt manage any checks today but will be doing over the weekend. It looks like im gonna be replacing the alternator but nevermind. If the alternator fixes it then it's still a hell of a lot of car for what i paid.

Does anyone know of anything i need to be wary of when fitting an alternator or if its a difficult job?

[cheshired5]

Originally Posted by andymull83

Does anyone know of anything i need to be wary of when fitting an alternator or if its a difficult job?

It's a pretty simple, if slightly awkward and cumbersome job needing a basic socket set.
You'll need to swap the clutch pulley over too which needs a £20 tool. Depending on where you buy your new alternator, they may swap it over but you'll have to take your old alternator in.
Alternator removal is one of those jobs where Haynes is pretty good at describing the procedure. It took me about 45 mins.

[GrahamBrown1]

Make sure you get the correct alternator as the wrong one will look the same and do the job but you will get power system service message on the dim. This is because there is also a green wire with a spade connector which I believe goes back to the cem to tell the computer the alternator is charging. Many members on here have had this issue and then had to swap and refit again.