Technical EPS electric power steering faults

[koalar]

Does the going left a new symptom or has it always done it ?

 

[kavil]

Voltage drop testing is pretty


Multimeter on volts , set to around 20V if it's not auto

Probe on either end of what you want to check, then load the circuit

For example the earth for the alternator

One end is the engine block, probe on here
Other end is the battery negative terminal

To load the circuit, pull a main relay out and crank the engine

Should be under 200mV

Let's assume it's not

The problem could be

Cable
Eyelet to gearbox
Terminal post to cable


Put the probes on the cable terminal and the battery terminal and crank the engine

Should be 0mV near enough

Repeat untill you find the voltage drop

To load the steering circuit, turn the steering with the engine on and the red warning light off

Yesterday i tried voltage drop with multimeter. Little Panda has 60mV voltage drop on earth in general. Max drop that i could get is on really rusty stock absorber nut and battery pole and even that was 120mV so almost everywhere on the motor bay is well under 200mV. I think bad earth really is not the issue. I will try it again with the eps as described by koalar.

 

[koalar]

Voltage drop while cranking?

60mV is too low/good even on a working car

 

[crossed up]

Does the going left a new symptom or has it always done it ?

RIght?
Yes, before the EPS failing, it drove straight & true, steering the same both ways.

 

[koalar]

RIght?
Yes, before the EPS failing, it drove straight & true, steering the same both ways.

Sounds like either

Something wrong withe the steering / suspension


Or the torque sensor gone

It does not sound like a power issue


First job is read the code and try a recalibration

 

[crossed up]

Sounds like either

Something wrong withe the steering / suspension


Or the torque sensor gone

It does not sound like a power issue


First job is read the code and try a recalibration

When the EPS stops working, steering operation is fine - just heavy.

Shall get the codes read.
What is needed for recalibration?

 

[koalar]

It's unlikely but it worth a shot, the centre straight ahead is set via software, 2 minutes to plug a computer in while the wheels are straight ahead


Also worth reseating the electrical connector under the ignition switch, but you will have to remove the plastic

 

[kavil]

Voltage drop while cranking?

60mV is too low/good even on a working car

I tried few things today thanks to my wife. She sat behind the steering wheel and crank the engine etc.
Engine Working, No steerings, stationary Vehicle.

Probe on Battery Negative, other probe on rusty shockabsorber nut 30mV (0.030v)​

Probe on Battery Negative, other probe on Engine block 15mV (0.015v)​

Probe on Battery Negative, other probe on Klimacompressor 13mV (0.013v)​

Main Relay removed, engine cranked many times

Probe on Battery Negative, other probe on Engine block (near Oil cap) 269mV peak and 180mV during 3 seconds cranking​

Probe on Battery Negative, other probe on Main Earth on the Chassis (near Gearbox) 210mV peak and 147mV during 2.5 seconds cranking​

Probe on Battery Negative, other probe on Batterypole cable 55mV peak and 42mV during 3 seconds cranking​

​

Engine Working, CITY mode on, No fault on the dashboard, full left to right many times

Probe on Battery Negative, other Probe on Engine Block 425mV peak and 30mV idleing, 29-47mV during steering left to right.​

​

​

Edit: For some reason i am not able to upload the city mode video, maybe due to its video data size.​

 

[kavil]

 

[koalar]

Yep engine block ground is in the right ballpark

You now need to check the earth for the EPS motor under load

That from the battery negative terminal lower arrow

To the motor ground eye top arrow

While turning the steering

What symptoms are you having

 

[kavil]

My symptoms are losing power steering. We already discussed about the details many times here. You helped me greatly but unfortunately i am not able to solve it. Failure Frequency increased as the weather worsened in Switzerland. I will measure the voltage drop on the EPS ground and eyelet soon.

I am thinking it paralel connecting 2 batteries to increase voltage buffer maybe. I do not know if that makes any sense at all or will pose a danger etc but i am just thinking about it. Would that make any sense? If so what would be best approach for such solution? Can i just bolt a jumper cable and run it along the engine compartment back to luggage compartment for example?

I know it sounds silly but this EPS failure is taking its toll on me and my wife. It became extremely frustrating.

 

[koalar]

Bad earth can only be check by checking voltage drop while under load

I have a good example here, even though it's a Suzuki not a Panda

It's got a fault earth but visibly it looks absolutely fine

If it's worse in cold weather or at the start of journey it's as close as you can get to 100% to a power problem not a problem with the EPS, there will always be an exception but I have never seen one


As for jumper leads, it hard to get any meaningful data using crocodile clips as you don't know how good the connection is


An old battery to starter motor lead or similar can be used, and eye on both ends, from the battery negative bolt on top of the terminal to bolt holding the gearbox selector cables is a good starting place


For me it's easier just to measure though

 

[kavil]

Yep engine block ground is in the right ballpark View attachment 450537


You now need to check the earth for the EPS motor under load

That from the battery negative terminal lower arrow

To the motor ground eye top arrow

While turning the steering

View attachment 450538


What symptoms are you having

Today I just checked the Motor ground eye and the battery negative terminal and had 0.007v (7mV.) i tried other cables as well which gave similar numbers. During the process my wife violently turned the wheel on a concrete floor to load the steering electrical motor.

It seems this eyelet is not the cause of Bad earth as well. Where should be the next point to control?

 

[koalar]

Today I just checked the Motor ground eye and the battery negative terminal and had 0.007v (7mV.) i tried other cables as well which gave similar numbers. During the process my wife violently turned the wheel on a concrete floor to load the steering electrical motor.

It seems this eyelet is not the cause of Bad earth as well. Where should be the next point to control?

Correct, result is normal, problem lies elswhere

Is the failure more frequent now the weather's getting colder

Have you read the codes, although the codes aren't conclusive

 

[RFollia]

Hi all.
Remember my post in this thread stating EPS failure after alternator renewal?
And codes C1003 and c1007 of which FIAT wortkshop, thanks to you, said the fault was not in EPS?
Well, workshop thought the other way round and insisted on EPS module be rebuilt, which they did and later did no find where the module was. 400 euros and 2 months wait EPS issue is still not solved. Had a loan car but as soon as the engine started the red steeing wheel was lit on the dash.
But now it was stranger. In cold or hot weather, after 1st start, EPS does not work and red steering wheel is always lit. When braking it goes out.
After say 9 miles drive and a restart goes fine.
But the weirdest thing. C1003 and C1007 are gone. Now there is another code, one that makes me cringe: C1250... interference on drive wheel... (but nothing else).
As if one of the sensors or rings were bad, or the ABS module itself.
But here the funniest thing is ABS lifht, always out, except for Key on engine off (self test when starting).
I disconnected as a test rear sensor and presto, ABS light on, which required restart and code erasing.
Then I checked all connectors, unplugged ABS module and plugged it again, all with car switched off, of course. Checked all fuses and relays, and that afternoon EPS worked even though red steering symbol was lit up in the dash.
According to other posts, C1250 has to be with one ABS ring or ABS module, but in other cases ABS light was on, which is not my case
Something I could look at, before I go mad? (I also ave the 3 amigos in my LR disco, which will require a fuse fuse box rebuild).
Might it be a bad earth, or a cold solder in fuse box, or an ABS or EPS relay? Are all EPS relays in the module itself?
Best regards

 

[koalar]

Nothing points to the EPS

C1003, vehicle speed error

C1007 battery faulty
C1250 ABS has detected a difference of more than 6 km/h from that of the others.


EPS needs valid speed signal to work because of a speed error it's will shut down


Graph all four and sensors and take it for a drive, take a snapshot when the EPS fails, the corner that different is the one to concentrate on.

Check for metal dust and filings, overheating wheel bearing, too much play in bearing, scratches on the end of the sensor, sensor not fitted correctly causing too much gap

New to you cars its also worth if any sensors have been changed before for cheap eBay specials, some cheaper alternatives aren't reliable or don't last long

 

[kavil]

Correct, result is normal, problem lies elswhere

Is the failure more frequent now the weather's getting colder

Have you read the codes, although the codes aren't conclusive

There is no failure codes using OBDII tool. Failure frequency is same, It is getting colder but i can not say it increased. it happens time to time, some days 2-3 times. somedays without a failure. It always goes back to normal after quick shutdown restart of the engine.

 

[koalar]

There is no failure codes using OBDII tool. Failure frequency is same, It is getting colder but i can not say it increased. it happens time to time, some days 2-3 times. somedays without a failure. It always goes back to normal after quick shutdown restart of the engine.

Code will be stored if the light comes on

Will your scanner read the body module

Most scantool only access the engine module

What scanner are you using

 

[RFollia]

Nothing points to the EPS

C1003, vehicle speed error

C1007 battery faulty
C1250 ABS has detected a difference of more than 6 km/h from that of the others.


EPS needs valid speed signal to work because of a speed error it's will shut down


Graph all four and sensors and take it for a drive, take a snapshot when the EPS fails, the corner that different is the one to concentrate on.f

Check for metal dust and filings, overheating wheel bearing, too much play in bearing, scratches on the end of the sensor, sensor not fitted correctly causing too much gap

New to you cars its also worth if any sensors have been changed before for cheap eBay specials, some cheaper alternatives aren't reliable or don't last long

Hi. thank you. I also checked for play in bearings. No play. Front ones were exchanged 3 years ago due to noise and the "ABS" side was inserted the right way round. Will remove sensors and spary them with brake cleaner just in case.. Rear drums and shoes were also exchanged 3 years ago.
And no problems since.
When you say "graph all four sensors" you mean I get a live reading of all ABS sensors and monitor the difference in wheel rotation? Don't know if my reader can allow that but will try. First I will remove each sensor and clean them. Will do the same with rear drums and rings and sensors, but will take some time as disco2 is first on the row.
Best regards and thank you.

 

[koalar]

When you say "graph all four sensors" you mean I get a live reading of all ABS sensors and monitor the difference in wheel rotation? Don't know if my reader can allow that but will try.

Yes

Sounds like one corner is lazy and reading more than 6 km/h lower than the other three

If you can identify the correct corner you have already eliminated three quarters of the work