Technical EPS electric power steering faults

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Technical EPS electric power steering faults

koalar

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First don't panic, the vast majority of power steering faults are normally simple and cheap fixes

especially if it starts failing mainly in your winter months

But unfortunately nobody can say change this or do that and it fix it. A lot of different faults will cause the same symptoms or the red light to come on.

These are from both my own experiences and what others have found, thanks everyone that's add to the knowledge base. But I could have easy missed things out. Or have made a mistake

First of the symptoms often tell more about the problem than reading the codes which can be confusing or inconclusive. A lot of advise is just to read the codes, this is what I always did and said until I found out that a low power situation can also throw a torque sensor error (two confirmed cases)

mainly fails only cold mornings, likely battery or earth

or

mainly fails in winter, likely battery or earth

or

on the way to work but not on the way back, likely battery or earth

mainly fails First few minutes of driving, likely battery or earth

mainly fails First few T junctions, likely battery or earth

mainly fails reversing into a parking space, especially as you press the brake, likely battery or earth

mainly fails when at low REVs, likely battery or earth

only fails when going over a bump, loose cable / earth

only fails when the roads are wet loose alternator belt none aircon model's

mainly fails as you slow down from a fast run loose alternator belt none aircon model's

squeal as you accelerate random red light loose alternator belt none aircon model's

totally random Red light steering fine or goes heavy, normally battery or earth

red light on or off steering feels funny in one direction. Faulty torque sensor is likely, thankfully rare

red light on or off random vibration of the steering wheel. faulty torque sensor is likely, thankfully rare

only fails on hard lock in one direction, faulty torque sensor is likely, thankfully rare

steering wheel turns on its own, faulty torque sensor, never seen on the Panda, but have on other delphi EPS

battery substation, this has fixed hundreds of cars, at least 4 cars for me.

its worth mechanically cleaning the battery connectors first, unknow how many this fixes as often just swaping the battery hides the true fix. Both the terminal posts and inside of the connectors need to free from oxides. You can't tell by looking at them. you need to remove a clean clean them mechanical, both inside of the connectors and the lead post. I use a green scouring pad

At least two people on this forum have had the battery tested okay by a garages fancy electronic tester, for the fault to be the battery. Often wasting weeks going round in circles. Also testing with a simple volt meter is a waste of time. I have had a battery with dead cells and measured well under 12V at rest but never failed on the steering.
If someone could come up with a reliable test, life would be so much easier. I have tried with several meters on faulty cars and none have shown any problems with the battery or alternator. Nine time out of ten you are just wasting time and effort.

Only if you have any early 1.1 with cassette play or a none original replacement radio will you need the code for the radio. Everything else (the vast majority) you can disconnect at will as the code is remembered

If you place the battery on charge overnight and it improves is highly likely its on the way out. If its over 5 year its also quite likely

I have two cars. By far the easiest way for me is to swap the batteries over. A very High percentage of problems is nothing more than the battery this is what I always try fist unless the symptoms say otherwise. Having a spare battery is a big help, as you dont want to needless buy a new battery, but I know of no reliable test

I then move onto the quick and free solutions

not sure what to call this but its fixed at least 4 cars permanently, one mine(lock to lock). Park up preferably grass or gravel, kinder to the tyres but not essential, raise the revs to around 2K and quickly move the steering from lock to lock 4 or five times. Also you can also try toggling between city mode and normal driving it in each for a few minutes, this is also known to have fixed a car permanently in the past.

Power steering motor earth, I know of two car this has fixed. You can't tell by looking, unbolt it and clean with a green scouring pad or similar. The earth for the steering motor is bolted directly on top of the battery earth post. I would like to point out the earth on top of the gearbox has nothing to do with the power steering. Its often one of the first things people suggest.
If the car turns over (cranks) fine it will be fine.

torque sensor reseat, rare but I have had this fix one car for me, unplug and spray with contact cleaner and plug back in

I know nothing about this but someone had success by removing the motor and turning it through 180 degrees

recalibration with software, as far as I know this has fixed one, you can use multiecuscan, delphi, WOW and possibly more

one person has spotted a faulty alternator via a cigarette lighter volt meter.

before you check the alternator its best to inspect belt is tight, (I have had one fail due to a loose belt, I suspect there should be more.) not cracked or missing sections

moving on to the alternator itself, as far as I know this has fixed one, this is how I test mine

Listen for noises, squeal, rumble or grinding

the bearing can be checked with some rubber Hose works like a stethoscope. Although I find it easier to just slip the belt off and see if the noise goes

Let the battery rest for a few hours after a run then connect a volt meter on DC volts leads on the battery positive and negative terminals It should read 12.5-12.65 volts.

Start the engine should be between 13.5-14.5 volts. Mine is 14.1V. If its low try wiggling the wires if it jumps up suspect a loose connection

turning on the main beam, rear heated windows and blowers on max, voltage should remain above 13 volts, rev the engine it shouldn't go above 15V

we are now running out of simple solution

if you now read the error code and it says power. I have missed something out. sorry possibly the earth block bolted to the footwell but have never heard of one failing

if you have torque sensor symptoms and only a torque sensor error your only option is either change the steering column or torque sensor

torque sensor replace, this had fix quite a few in the past, less so now, we have learnt more since the early days, so make sure that it has been cleaned(contact cleaner) and reseat first otherwise it might not be the fault, but just fixed by swapping out the old dirty connector for a new part with a clean connector

I would like to add. From my experience that it can be a pain to fix. But stick with it. I have done at least a dozen not just Fiats, Not a single one yet has required a major repair in the end. In fact the only part I have ever replaced is the battery. The rest have just been reseat, clean, recalibrate or tighten belt. The odds have to be in favour of a cheap and easy repair.
 
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By far the easiest way for me is to swap the batteries over.
Absolutely. The easiest way to rule out the battery is to exchange it for one which is known to be in first class condition; most battery testers aren't sufficiently able to carry out the kind of load test that's required for this purpose.

Second best is to remove the battery, bench charge with the best charger you can find and see if it makes a difference.

Fiddling about with a simple voltmeter is basically a waste of time.
 
just to avoid confusion

the earth location for the electronic steering motor is here, directly on top of the battery negative connector.

no Good looking at them. They need unbolting and cleaning with a green scouring pad or similar.

I also smear with a bit of petroleum gel although not strictly needed
 

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I'm the guy who solved a steering problem by changing the alternator. BUT I had already proved the battery and the earths.

New battery seemed to have fixed the issue but a month later it was back. Was the old battery really a scrapper? who knows?
Unless the alternator has packed up a voltmeter on a warm system tells you nothing. I detected the fault by noticing the that system volts were low for longer than I'd expect after cold start and getting the car out of our driveway using full steering lock would trip the steering. Restart often refused to reset the steering. A cheap voltmeter will show this volt drop, because voltage changes across the whole system when the battery or alternator are struggling.

Optimate charging the battery (overnight) seemed to help but the steering problem soon returned. I listened to the alternator bearings with a stick of doweling and it seemed louder than I'd expect but how should it sound? However, the bearings were not great with the belt removed so I fitted a new alternator. It was enough to make the decision. System voltage went up to 14.2V (was 13.8V) and the steering problem has gone away.

It gets even more confusing because my 100HP alternator was gradually seizing up due to corroded core and cracked casing. The brand new unit has never shown more than 14 volts (usually around 13.8V) but everything runs fine. The steering has never played up (famous last words) yet 100HP works the steering harder because default is high assistance and the wheels are wider.
 
Both my 100HP and the wife's Dynamic have had the red steering light come on recently with no symptoms of heavy steering so I can only assume it is an electrical gremlin. Both have gone away of their own accord and not returned. I have had a recent new battery but I am yet to clean up the terminals so that will be my next port of call on both cars.
 
couple of bits I missed

If the red light comes on and you loose power assistance (goes heavy)

pull over when its safe to, switch the engine off, wait a second or so and switch the engine back on

The vast majority of times it temporarily fix the problem.

if it starts to fail infrequently but then starts to fails on a more regular bases its likely to be a power problem.

Battery does not like to be left. It really needs to be used at least once a fortnight. If left for any longer it should really be disconnected and charged every few months

save me explaining why heres someone else's take.

 
another bit I missed shame I can't add to original post

Unsure if its a mechanical fault or the EPS

pull fuse F05. (early 1.2 and 1.1) Warning the steering will be much heaver than normal at slow speeds. A slight pull to either side is normal as most of the self centring is done by the EPS itself

also worth checking F05 for corrosion on the blades if you have a power problem

Also worth checking the tyre pressures. Never had this problem with a Fiat but have known other cars throw an error as you accelerate on a roundabout or loose farm tracks with a front tyre with low pressure. Tends to only throw an error as accelerating hard.
 
After a 4x2 took out two tyres on the motorway, and thought I had got away with it. The steering felt normal at dual and motorway speeds. It was only when I turned into my destination town that I felt the woolly steering and the pull to one side. That tyre was down to a few psi..
 
First don't panic, the vast majority of power steering faults are normally simple and cheap fixes

especially if it starts failing mainly in your winter months

But unfortunately nobody can say change this or do that and it fix it. A lot of different faults will cause the same symptoms or the red light to come on.

These are from both my own experiences and what others have found, thanks everyone that's add to the knowledge base. But I could have easy missed things out. Or have made a mistake

First of the symptoms often tell more about the problem than reading the codes which can be confusing or inconclusive. A lot of advise is just to read the codes, this is what I always did and said until I found out that a low power situation can also throw a torque sensor error (two confirmed cases)

mainly fails only cold mornings, likely battery or earth

or

mainly fails in winter, likely battery or earth

or

on the way to work but not on the way back, likely battery or earth

mainly fails First few minutes of driving, likely battery or earth

mainly fails First few T junctions, likely battery or earth

mainly fails reversing into a parking space, especially as you press the brake, likely battery or earth

mainly fails when at low REVs, likely battery or earth

only fails when going over a bump, loose cable / earth

only fails when the roads are wet loose alternator belt none aircon model's

mainly fails as you slow down from a fast run loose alternator belt none aircon model's

squeal as you accelerate random red light loose alternator belt none aircon model's

totally random Red light steering fine or goes heavy, normally battery or earth

red light on or off steering feels funny in one direction. Faulty torque sensor is likely, thankfully rare

red light on or off random vibration of the steering wheel. faulty torque sensor is likely, thankfully rare

only fails on hard lock in one direction, faulty torque sensor is likely, thankfully rare

steering wheel turns on its own, faulty torque sensor, never seen on the Panda, but have on other delphi EPS

battery substation, this has fixed hundreds of cars, at least 4 cars for me.

its worth mechanically cleaning the battery connectors first, unknow how many this fixes as often just swaping the battery hides the true fix. Both the terminal posts and inside of the connectors need to free from oxides. You can't tell by looking at them. you need to remove a clean clean them mechanical, both inside of the connectors and the lead post. I use a green scouring pad

At least two people on this forum have had the battery tested okay by a garages fancy electronic tester, for the fault to be the battery. Often wasting weeks going round in circles. Also testing with a simple volt meter is a waste of time. I have had a battery with dead cells and measured well under 12V at rest but never failed on the steering.
If someone could come up with a reliable test, life would be so much easier. I have tried with several meters on faulty cars and none have shown any problems with the battery or alternator. Nine time out of ten you are just wasting time and effort.

Only if you have any early 1.1 with cassette play or a none original replacement radio will you need the code for the radio. Everything else (the vast majority) you can disconnect at will as the code is remembered

If you place the battery on charge overnight and it improves is highly likely its on the way out. If its over 5 year its also quite likely

I have two cars. By far the easiest way for me is to swap the batteries over. A very High percentage of problems is nothing more than the battery this is what I always try fist unless the symptoms say otherwise. Having a spare battery is a big help, as you dont want to needless buy a new battery, but I know of no reliable test

I then move onto the quick and free solutions

not sure what to call this but its fixed at least 4 cars permanently, one mine(lock to lock). Park up preferably grass or gravel, kinder to the tyres but not essential, raise the revs to around 2K and quickly move the steering from lock to lock 4 or five times. Also you can also try toggling between city mode and normal driving it in each for a few minutes, this is also known to have fixed a car permanently in the past.

Power steering motor earth, I know of two car this has fixed. You can't tell by looking, unbolt it and clean with a green scouring pad or similar. The earth for the steering motor is bolted directly on top of the battery earth post. I would like to point out the earth on top of the gearbox has nothing to do with the power steering. Its often one of the first things people suggest.
If the car turns over (cranks) fine it will be fine.

torque sensor reseat, rare but I have had this fix one car for me, unplug and spray with contact cleaner and plug back in

I know nothing about this but someone had success by removing the motor and turning it through 180 degrees

recalibration with software, as far as I know this has fixed one, you can use multiecuscan, delphi, WOW and possibly more

one person has spotted a faulty alternator via a cigarette lighter volt meter.

before you check the alternator its best to inspect belt is tight, (I have had one fail due to a loose belt, I suspect there should be more.) not cracked or missing sections

moving on to the alternator itself, as far as I know this has fixed one, this is how I test mine

Listen for noises, squeal, rumble or grinding

the bearing can be checked with some rubber Hose works like a stethoscope. Although I find it easier to just slip the belt off and see if the noise goes

Let the battery rest for a few hours after a run then connect a volt meter on DC volts leads on the battery positive and negative terminals It should read 12.5-12.65 volts.

Start the engine should be between 13.5-14.5 volts. Mine is 14.1V. If its low try wiggling the wires if it jumps up suspect a loose connection

turning on the main beam, rear heated windows and blowers on max, voltage should remain above 13 volts, rev the engine it shouldn't go above 15V

we are now running out of simple solution

if you now read the error code and it says power. I have missed something out. sorry possibly the earth block bolted to the footwell but have never heard of one failing

if you have torque sensor symptoms and only a torque sensor error your only option is either change the steering column or torque sensor

torque sensor replace, this had fix quite a few in the past, less so now, we have learnt more since the early days, so make sure that it has been cleaned(contact cleaner) and reseat first otherwise it might not be the fault, but just fixed by swapping out the old dirty connector for a new part with a clean connector

I would like to add. From my experience that it can be a pain to fix. But stick with it. I have done at least a dozen not just Fiats, Not a single one yet has required a major repair in the end. In fact the only part I have ever replaced is the battery. The rest have just been reseat, clean, recalibrate or tighten belt. The odds have to be in favour of a cheap and easy repair.
I have a light and check power steering warning on a panda 100 hp.
The car has been sorned for over a year and no mot, so can’t take it out for a run.
Ive just replaced the battery so don’t think that’s the cause.
I checked the alternator voltage 14.2 v and 13.97v when loaded. (Although there is no squealing noise the belt does seem flexible when twisted?)
I cleaned the terminals and checked from the pin where the torque sensor connects ( black wire) and ground and it’s good (0.6 ohms) so don’t think it’s a bad neutral there. I only have haynes manual which isn’t much use circuit diagram wise.
I have cleaned and re -seated the connector, still the same.
Would it be worth changing the alternator belt first before fearing the worst?
 
I have a light and check power steering warning on a panda 100 hp.
The car has been sorned for over a year and no mot, so can’t take it out for a run.
Ive just replaced the battery so don’t think that’s the cause.
I checked the alternator voltage 14.2 v and 13.97v when loaded. (Although there is no squealing noise the belt does seem flexible when twisted?)
I cleaned the terminals and checked from the pin where the torque sensor connects ( black wire) and ground and it’s good (0.6 ohms) so don’t think it’s a bad neutral there. I only have haynes manual which isn’t much use circuit diagram wise.
I have cleaned and re -seated the connector, still the same.
Would it be worth changing the alternator belt first before fearing the worst?
no, it charging fine, as long as its not cracked or slipping no point

couple of quick questions

was the steering fine before it was taken off the road

is the red light on all time

does steering go heavy as well as the red light.

First thing I would try would be put the battery on charge. A new battery should be charged every two months, often they are left on the shelve longer than this before they are sold

Second I would raise the revs to 2K and rapidly moving the steering full left to full right lock a few times
 
no, it charging fine, as long as its not cracked or slipping no point

couple of quick questions

was the steering fine before it was taken off the road

is the red light on all time

does steering go heavy as well as the red light.

First thing I would try would be put the battery on charge. A new battery should be charged every two months, often they are left on the shelve longer than this before they are sold

Second I would raise the revs to 2K and rapidly moving the steering full left to full right lock a few times
The light wasn’t there before. It stays on permanently. Can hear the motor going and steering isn’t heavy , even when stationary.
The guy i bought it off had just changed the top mounts and suggested that maybe if get wheel alignment done it might fix it. As i said, it was ok when i bought it , but wasn’t driven . I have already charged the battery and tried the lock to lock , but no joy yet.
 
The 100HP steering default is maximum assistance. The "Sport" button makes the accelerator pedal more aggressive and reduces the steering power. If the steering works on Sport but not on normal you have a steering motor issue.

My 100HP was unused for about 2 months in the first Covid lockdown. It refused to start - fully charged battery lots of motor action but no start. I searched for faults (fuel pump, blah, blah) nothing found. I pulled every fuse and tested for continuity - all fine. I pulled the relays and they all tested fine. However once all back in the car it just started like it always does. I assume the problem all along was a dirty contact or sticking relay. We will never know for sure.

Suggest you pull every relay and test them with a 9V PP3 battery and a test meter for continuity. Or just buy a new relay and swap it with the existing relays one-by-one.
 
The light wasn’t there before. It stays on permanently. Can hear the motor going and steering isn’t heavy , even when stationary.
The guy i bought it off had just changed the top mounts and suggested that maybe if get wheel alignment done it might fix it. As i said, it was ok when i bought it , but wasn’t driven . I have already charged the battery and tried the lock to lock , but no joy yet.
Thats good

Working before being SORN and change of battery. It more than likely to be caused by the part replaced.

The bad news is you can't mot the car with the red light on. They can get into a knot. Normally the lock to lock sorts this. Try doing this a few times in both city and normal modes.

If you have another car try swapping the batteries. Its not unknow to get a fail on fit part. We have had one on here in the last couple of weeks

Its worth checking the battery resting voltage when the car hasn't been started for a few hours on a new battery it should be 12.6V

Also on First crank it shouldn't drop below 10V however multi meters are slow to register but will give you an idea. On my expensive meter if it says 11V its really going down to 10.5V ish


If you have another car swap batteries
 
The 100HP steering default is maximum assistance. The "Sport" button makes the accelerator pedal more aggressive and reduces the steering power. If the steering works on Sport but not on normal you have a steering motor issue.

My 100HP was unused for about 2 months in the first Covid lockdown. It refused to start - fully charged battery lots of motor action but no start. I searched for faults (fuel pump, blah, blah) nothing found. I pulled every fuse and tested for continuity - all fine. I pulled the relays and they all tested fine. However once all back in the car it just started like it always does. I assume the problem all along was a dirty contact or sticking relay. We will never know for sure.

Suggest you pull every relay and test them with a 9V PP3 battery and a test meter for continuity. Or just buy a new relay and swap it with the existing relays one-by-one.
they have power to everything. The EPS is working. Not sure how this could help and may introduce a new problem. Just the computer is reporting a problem
 
I am saying that setting the car to Sport mode puts less stress on the steering motor. If it clears the fault you have found the issue.

Pulling fuses and relays cleans the contacts. How can that introduce problems? It could be as simple(?) as a sticking relay that will wake up when operated off the car. A 9V PP3 battery will not overload the relay.
 
I am saying that setting the car to Sport mode puts less stress on the steering motor. If it clears the fault you have found the issue.

Pulling fuses and relays cleans the contacts. How can that introduce problems? It could be as simple(?) as a sticking relay that will wake up when operated off the car. A 9V PP3 battery will not overload the relay.
pulling fuses has a danger. Damaged pins, putting back in the wrong place. The only one that needs to be touched is F05 which we already know is okay as the EPS is powered up


Repair electronics is the only thing I did for 20 years. Moving and disturbing things when you don't need to can get you into real bad trouble as you not only have to repair the original fault but the bent pin or broken wire the could have been introduced
 
Looking for some advice on a power steering oddity,this is a 2010 500 but I assume most issues would be the same. We had the column changed about 3 years ago,and ever since the the power assistance is fine when you’re stationary in both city and normal mode. However as soon as you get to 5mph all assistance is lost and the car is very slow to self centre. The garage that did have since checked the steering angle sensor,but haven’t got multi ecu scan. Any suggestions?
 
Looking for some advice on a power steering oddity,this is a 2010 500 but I assume most issues would be the same. We had the column changed about 3 years ago,and ever since the the power assistance is fine when you’re stationary in both city and normal mode. However as soon as you get to 5mph all assistance is lost and the car is very slow to self centre. The garage that did have since checked the steering angle sensor,but haven’t got multi ecu scan. Any suggestions?
Leave it with me. Out an about for the next few hours. Sounds like a speed sensor problem as the assistance is dependent on speed.

Any error light
Trip computer working
Speedometer

It’s not a normal failure mode we see on the panda
 
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