Hi all and thanks in advance for your help. I own a 2005 Stilo Xbox edition which ive had since new. Ive had a long list of things done to the car (repairs not mods) but I like the car so I dont mind. The only thing is now, with money tighter than ever the car breaking down is totally unwelcome so I'm trying to self diagnose the problem so I can get the best quote on repair (if I cant repair it myself.) I have read a lot of posts over the last week and im now just re-reading stuff and not sure what to do so if you could advise me id be really grateful.

Recently I had a problem with a sensor which meant the car juddered whilst driving. It happened twice and then the engine management cut in so I got it reset and has been fince since. This may be unrelated I dont know? Then one morning I started the car as normal, and after the usual checks the battery light came on and the power steering wouldnt work, 30 seconds later light went off, steering worked and I went about my day. The following morning, same thing and on day three as I drove to work the light came back on and my car became as steerable as a train at 40 miles an hour for a frightening moment then off went the light. It then came off and on again and gradually more regular intervals as I got it home.

I have since found that, if I sit with the car at 4k revs for about 20 seconds then the light goes off (steering back) and if I drop the revs the light comes on.
I then wedged the accellerator, and let it stay like that for 10 mins. Took the gas off and the light stayed off, tried to drive down the road but only got 100 meteres. If I get the revs up though the light goes out.

Ive tested the earths as per deckchairs guide and they are good. Ive checked the d4 as per deckchairs guide and its dry dry with no signs of ever being wet.

The battery is 1 year old and isnt losing power. Alternator makes no odd noises, all belts tight.

I'm guessing I just need to go get a new alternator but is there anything else simple I can do here? And is the engine sensor fault possible related?
I got the codes at home from when that fault was reset if you need them but the mechanic said there was nothing unrelated to the sensor on there.

Thanks in advance for your help.

Can't remember what thread I read it from or whether It's just popped into my head for no reason but I think the power steering is the first thing to be disabled by the ecu when the available current drops too low. I'm 99% sure of that.

So with that in mind I would think it's a battery or alternator issue, but you say the battery's fine so leaves us with the alternator. Has it ever been changed during your ownership of the car? Check the charge voltage of the battery, when the car's running idle stationary stick a multimeter across the terminals of the battery and you should have 14v. Get a friend to increase the revs and see if the voltage shanges, it shouldn't.

Thanks for your response. Yeah I read that too. To be fair I havent checked that yet. The bit that niggles me is that, if the light goes off when the revs are up then the alternator must be working and giving out enough current? Its only when the revs drop that the current falls too low and then the light pops on again and i have no steering. I'm no mechanic though and I only know what iver read in these forums.
The Alternator has noever been changed on this car no.
I just wanna leave work and go tinker but I cant.

It can be one of 2 things, either the alternator or the battery.

If the light goes up on high revs it can mean that either the battery is finally getting enough power back to trigger the sensor to say it's alright which points to the alternator or the battery is shot and only gets some charge when you really put some current into it.

I say it's a 70-30% in favor of the alternator for being bad.

Take a battery from a friend's car, any type would do as long as it's at least 50ish amps and see if the alternator light goes off. If it doesn't, then it's the alternator. If it does, keep the battery for 2-3 days or 50ish miles and see how that works for you.

You can also diagnose the car if possible, really easy to check the alternator to see if it provides enough power.

Thanks Vladof. When you say its 70-30 in favour of the alternator do you mean that you think its most likely the alternator thats bust?
The battery is a year old, I could take it for testing if you think its worth doing?
You said its really easy to check the alternator to see if it provides enough power, how do I do that? Or is that the test that Markthompson4 suggested?

I too would say the alternator.

i'd say alternator, but it needs testing using a multimeter..

see here - http://www.carbasics.co.uk/How_to_test_your_alternator.htm

paul8977 said:

Thanks Vladof. When you say its 70-30 in favour of the alternator do you mean that you think its most likely the alternator thats bust?
The battery is a year old, I could take it for testing if you think its worth doing?
You said its really easy to check the alternator to see if it provides enough power, how do I do that? Or is that the test that Markthompson4 suggested?

Click to expand...

Hi,

Yes, I think that most likely the alternator is gone. I say this because a dead battery doesn't really generate any real faults, but is hidden under anything like power steering failure, ASR and ESP failure, anything the ECU thinks works best just to keep the voltage up. But when you get that with the alternator fault, it's most likely the alternator and the other errors are caused by a low battery that fails to be charged by the faulty alternator.

It is really easy to check if you hook up the car to a computer with FES (Fiat ECU Scan) because it can tell immediately what triggered the fault. The test that Mark suggested also works, you could try that.

I do suggest swapping batteries with a mate other than testing it, because batteries can perform different on different cars. The Stilo is a major consumer so it needs a really good battery to make it work properly. You may put it on another car and be surprised to see that it works just fine there, and it could still be the battery causing the issues. This is why I suggest, take a mate's battery put it in, see how it goes.

Ultimately, if nothing solves this, you may need to plug the car into FES and see exactly what's wrong. Nevertheless, scrappies are full of working alternators so it's a cheap fix.

Cheers.

I have that error with my alternator at startup only. Alternator light on and no steering power. After a blip on the throttle all is good. His is permanent and it should be a sign of failing alternator.

Change it yourself it's almost easy and cheap.

Thanks for all your posts. I ran the alternator tests this morning. Engine off I got 12.42 engine on I got 14.04 and revving made no difference.
I drove the car to a local garage and the battery light was off most of the way but did come on a few times and was on for the first 5 mins of my journey.
After the majority of you suggesting alternator I called around for the best price and took it in to get done and I'm just hoping that's the problem. I will update you when I hear more. If you have any other suggestions then I will forward them to the mechanic.

Battery voltage is fine and charge voltage is fine as well, battery and alternator are ok by the looks of things :s

I'm afraid it may be a lost cause changing the alternator, though you should wait around long enough for the fault to come up to see what the multimeter shows. Get them to check the earth from the alternator is secure.

Ok so the alternator tests as fine at the garage, but still no power steering. They have suggested that I get a new alternator fitted but have also said there is no guarantee it will fix the problem. The earth is apprantly fine and they cant find anything else wrong with it. They said the alternator could be overcharging and causing the same problem. I cant afford to throw money at this and I dont think I can do it myself. Anyone got any advice?

Swapping batteries?

Hi Vladof and thanks, unfortunately I dont have a friend who I can swap a battery with. I'm in london and have only been here a year and dont know anyone with their own car, most people done have one and the few I know that do have company cars. I have asked the garage to try a different battery though and see if it works. I'd be bloody glad if that was the case.
I will update you once I hear back

I say battery too. A dying battery can show healthy voltage if the car has been running recently. But under load it could be struggling to take what the alternator is throwing at it.

The garage said they tried a different battery that was slightly more powerful and the fault remained exactly the same. High revs make the light go out, low revs and it comes back on.
They dont think it is the power steering ECU as the power steering light doesnt come on. They've tried all the cables and connections, checked the fuses and all looks good, all they can suggest now is the alternator. He said 88% certain its the issue. So unless anyone has any further ideas......I guess I will have to get a new alternator and pray.

Hi: Your best bet would have been to take it to an Auto Electrician to have it checked properly. What part of London are you in ?



Andy

Thanks Andy. Sadly I missed this yesteray and instructed them to go ahead with fitting a new alternator. If it doesnt work then I will, after I finish crying, go with your suggestion.

Hi mate: Theoretically if the Alternator does'nt cure it then they should re-fit your old 1 for you, at the end of the day they are the one's who tested the car & said that was what was causing your problems. Having said that i'd be about 90% sure that the Alternator or it's wireing is what's causing your problem, it's quite a common thing on modern cars with Motorised power steering.
If it does'nt cure your problem then drop the other Andy an email & he can sort it for you.
Be sure to let us know how you get on.




Andy

Yes after reading all this I will be surprised if the new alternator doesn't fix this.