Technical Fiat Stilo loss of power steering/battery light

[notveryclevertrevor]

Hi. New to this.
I have a Fiat Stilo 1.9 JTD 56 plate.
The power steering has gone off.
The power steering warning light comes on at start up but goes off as it should.
The battery warning light stays on but I have 14v at the battery and also at the main power feed to the power steering unit itself (under the steering wheel)
I am at a loss.
I took some connectors off and put them back on again (no obvious signs of problems) and it did work briefly and battery light went out. But after a drive and turning engine off again the fault has returned and I haven't been able to get it to work again even though I have took some of the same connectors off and reconnected them again.
Seems like a dodgy connection somewhere rather than anything drastic but has failed MOT.
Any ideas?
It's likely someone will have come across this before.
Big thanks

 

[varesecrazy]

I thought you had lost the serpentine belt for a while there..

But if you have 14 volts its obviously charging ok..


First easy test

Add a jumplead from battery negative to engine metalwork.. in case the earth connection is failing

 

[notveryclevertrevor]

Cheers bud I'll try that

 

[notveryclevertrevor]

CAN error

Alternator status (from CAN) not being recharged

Battery light stays on but 14v at battery so im guessing alternator is charging.

Power steering isn't working.

Anyone come across this. It's driving me to distraction

 

[Ralf S.]

Re: CAN error

If you turn the high bean headlights on at idle, and then rev the engine up to c.3000rpm, do the lights get brighter?

What's the voltage across the battery terminals when the engine is running (at a fast idle/1500rpm)?

Where are you seeing the "Alternator status" message?




Ralf S.

 

[notveryclevertrevor]

Lights don't get noticeably brighter

I have 14+ volts at battery so I'm thinking alternator is actually charging. Plus ive been driving it for a while and surely if it wasn't my battery would be flat by now?

Error code was from a diagnostics machine that a friend plugged in

Appreciate your help

 

[Ralf S.]

The alternator and its components sound okay, you're right.

I wasn't sure whether the Power Steering is a coincidence but if it's controlled by the Body Control Module (I suspect it is) then a fault with that, and an inaccurate red alternator light might point to a BCM problem.

You can't just swap the BCM to try it, unfortunately, since the immobiliser chip lives on there.. so a straight replacement BCM would make the car not start.

Do you have power at the power steering plug? If not, that would make the steering motor the culprit (and the red light is something else). If you have no power at the plug, then it would be a case of tracing the wiring back towards the fuse box until you get some joy. I suspect you will reach the BCM without finding any breaks or problems, etc.

The BCM gets a jumble of wires/connectors in and sends current, via various pins, out.. but it's essentially just a PCB. If you can get hold of a wiring diagram that shows which pins the steering uses, if any, then that might help diagnose whether the BCM is working properly or not.

I don't think the steering and the light are connected, other than they may both be caused by a common component that's failed.. (i.e. some circuit on the BCM). BCM's can be usually be diagnosed by ECU repairers, if you don't get anywhere.


Ralf S.

 

[notveryclevertrevor]

Cheers Ralf.

Yes I have power at the feed for the power steering.

A couple of times I've managed to get the power steering to work more by good luck than anything. Once I slammed the passenger door to trap my dogs lead in it (!) the other time was after removing and refitting various connectors. On both occassions the steering worked and the battery warning light went out so im guessing they are part of the same problem

Sorry to be a pain but what is the BCM? Is it the box of tricks connected to the battery compartment or the box of tricks in the driver footwell (below right of steering wheel) if its the latter that was what i took the connectors off (one of the things) and refitted them and it worked (briefly) but I havent been able to replicate

 

[Ralf S.]

That's good news then, since it sounds like an electrical connection problem.. and "jiggling it about" may get everything to work.

The BCM (Body Control Module) is a big plastic box (like a fuse box on steroids) that lives behind the fuse box under the dash. If you remove the lower part of the dashboard corner, which has the hatch to the fusebox in it, that will give you a bit of space to see everything. The BCM is just a plastic case (all the electronics are inside) so you can't easily break it.

From memory the fusebox can rotate outwards and out of the way, so then you would see the BCM. That has a load of electrical connectors and plugs in it (luckily all different, which makes replacing them in the right place a bit easier). If you disconnect everything, take the beast out and give the pins a clean and a squirt of electrical cleaner, then replace everything, the trauma of all that might fix the loose connection issue.

If the electrical steering issue is closer to home, then look for an earth connection on the body/inner wing that is as close to the steering rack as you can find. It will *probably* be the one the steering uses. Take the bolt out, clean the metal faces with emery paper.. and where it touches the body, then put it all back together, with a blob of grease on top, to keep it dry/un-corroded. That might do something too.


Ralf S.

 

[notveryclevertrevor]

Cheers Ralf. Appreciate your help bud

 

[notveryclevertrevor]

I took all the body computer and fuses out from under the steering wheel. Contact cleanered em to death. Put it all back together. No better.

But.

If i disconnect the two chunky power feeds into the body computer the power steering works so i'm guessing the actual power steering module and the wiring to it are both ok. Would that sound right?

Seems to me that whatever tells the computer the alternator is charging is saying it isnt (even though im pretty sure it is) and so the computer is shutting down the power steering to save power

Does that sound likely?

I know its doing my head in ?

 

[notveryclevertrevor]

I have an error code

Alternator status (from CAN) not being recharged

 

[Ralf S.]

Hmmmmm.... that rings a faint bell.

If I remember correctly, when my alternator packed up (the pulley bearing failed) I had a permanent red alternator light, as you would... and I *think* the steering was disabled (though I can't 100% swear to it now) .

Your alternator is obviously charging the battery but it could be mis-reporting what it's doing. It has a few components on it, and I dunno if an auto-electrician can give it a once-over, otherwise, if you're happy you could take a punt just stick a new alternator on there.

If it's not the alternator then I think you're right and would mean that "something" in the BCM/ECU is not getting the message that the alternator is fine... which sounds more serious.

For alternators, I'd buy a Denso. It's the OE manufacturer and it'll last another 15 years, which is plenty. I bought a "501" (I have a 2004 1.9 JTD 115bhp). If your JTD is different then a "501" won't fit.

https://www.ebay.co.uk/itm/18150857...QMjHzo3C3rBUDg%3D%3D|ampid:PL_CLK|clp:2334524

If you go "recon'd" (all new parts but re-cycled body.. though still looks like new) make sure that the seller doesn't want your old alternator as part of the deal. A slightly more expensive item that you don't need to add your postage costs to, will work out cheaper.



Ralf S.

 

[notveryclevertrevor]

Today I have taken the two sides of the fuse box (near the battery apart) which involved taking the connectors off the back and then put it all back together and it all worked (except some of my lights were permanently on).

As i hadnt done anything to the alternator im guessing thats ok.

I took it all apart again reassembled and the light problem had been cured but the original one returned.

Im guessing its either the fuse box itself or something to do with the connectors into it.

Since then I have taken them all off loads more times but not got the alternator/battery light to go out.

Im pretty sure its the connection between the alternator and the body computer rather than either of those actual components.

I would love to be able to check out the continuity of the circuit between the alternator and the body computer but i dont know how (i can obviously get to the alternator side but dont know where the other side of the wire is?)

 

[domtheboyo]

My 2005 MultiWagon 1.6 just developed this exact same issue after a long road trip. Just within the last 5 miles of the journey after a pit stop. Replaced battery but same issue. Sitting idle with multimeter on battery, idle intermittently drops/hesitates and battery voltage drops then bounces back up to 14v. Keeps repeating this every few secs. Battery light on dash and no power steering. Still drives fine, no codes or other electrical issues. Did you get it sorted? Was it the alternator or bad earth?

 

[domtheboyo]

My 2005 MultiWagon 1.6 just developed this exact same issue after a long road trip. Just within the last 5 miles of the journey after a pit stop. Replaced battery but same issue. Sitting idle with multimeter on battery, idle intermittently drops/hesitates and battery voltage drops then bounces back up to 14v. Keeps repeating this every few secs. Battery light on dash and no power steering. Still drives fine, no codes or other electrical issues. Did you get it sorted? Was it the alternator or bad earth?

After digging a bit more it seems Alternator is worth replacing so I ordered one. Hopefully this will sort it.