Technical Power Steering Saga Part Deux

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Technical Power Steering Saga Part Deux

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Ok I'm tearing my hair out here.

Purchased a refurbed steering unit which I was told didn't need a code.

Mechanically it's fine, works perfectly, city mode included.

BUT... It's throwing a U001 Can signal error.

I purchased a multimeter and checked out the earths at the weekend as per the elearn diagnostic.

Measured battery voltage, then voltage across the connector to the unit.

Static load I had a 0.2V drop. Dynamic load there was no drop in voltage.

So I'm assuming the earth's are all ok.

Where the hell do I go from here though? Got my MOT in a month and it's going to fail even though there's nothing wrong with it.:bang::bang::bang:
 
Ask the people who you bought the refurbised item from for help..error code wasnt there before ...was it?....Im making an assumption that you cleared the code...

The unit DID have matching numbers to your original one...didnt it?
 
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Ask the people who you bought the refurbised item from for help..error code wasnt there before ...was it?....

I didn't check for a code before removing the old one. It mechanically sounded awful then failed so it was obviously buggered

Im making an assumption that you cleared the code...

I did after installing the new unit and it came straight back

The unit DID have matching numbers to your original one...didnt it?

Indeed it did.

They sent me a second unit to try so they're now saying the fault is at my end. Damned if I can work it out though.
 
Did you do the proxy alignment to the new PSU?
If not then it makes sense it won't communicate on the can network.

You'd nee access to a oscilloscope to test the car's CAN network... you only need to see if data is transmitted on those wires with the PSU connected and disconnected.
 
Bernie,

Could you lay your hands on a wiring diagram for the Can connector please?

Cheers. :)

My next plan of attack is to check the resistance on the CAN signal wires with the unit attached and unattached.

If that's ok I don't have an oscilloscope but I have got a full version of multiecuscan.

I'll hook it up and see what data I can graph from the module.

If anyone's familiar with the software and can offer any hints I'd appreciate it.

Failing that it's going to be a trip an auto electrician.

Thanks,

Thomas
 
Hi Thomas,

sorry that's all I can find ...

BRs, Bernie
 

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Morning All,

Found a pinout for the can plug for the steering module and checked the power to that as well. All good.


Hooked up the laptop and got the error code, stayed after clearing.


Done proxi alignment and position calibration ok.


Tried to do torque calibration and it came up with an out of range error. Any ideas on this one?


Few screenshots below in case they are of use.
 

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The PSU module is probably OK..since it communicates and you can see it/connect to it with MES.
The column sensor might be bad. So that might be the reason why it's saying out of range. Trying to send sensor position to the can network...
 
The column sensor might be bad. So that might be the reason why it's saying out of range. Trying to send sensor position to the can network...


Thanks Aurick, much appreciated.


Is the column sensor part of the power steering unit itself?


Thanks,

Thomas
 
I think that steering column sensor is not present (as MES says) because you have vehicle with ABS. Are you sure that you choosed right car/model in MES? Becuase if you choose similar model (like EVO instead of Grande) , not all parts of diag are working properly. That's my experience... For example first I choosed Grande, and I was not able to reset ECU's learned parameters. After that I choosed Punto 1.4 8v 2012+ or something like that and reset was working OK...little chance...but still some chance...maybe you can make Proxi Allignment procedure again with different car model...
 
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Ok found a guide to the column sensor. (Attached PDF)

Couple of things spring to mind. The column sensor on the reconditioned one has the cable inside. (My old unit had the plug on the outside like the one on the PDF) Wondering if it's possible when they reconditioned it, they installed the wrong item.

Looking at the end of this document does the wheel have to be at -144 degrees/ 0 torque when you perform the position calibration?

If so I can potentially try that in the software again tonight.

Thanks,

Thomas
 

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I've found that the CAN signal plug into the power steering module is a bit past it. :rolleyes:

It's missing the red tab and is a bit wobbly. It's gotten worse in the last day or so and has started throwing an ABS light as well now.

Spoke to the parts department who said they couldn't supply a new connector!:bang:

After a lot of trawling I found this Delphi connector. Minimum order of 10, £12.95 delivered! :eek:


:confused:QUESTION: For those more experienced with auto electrics than me, how sensitive are the CAN connectors to loose/wobbly connectors. I'm going to order a pack of these and see if it helps the problem out.

Thanks,

Thomas
 

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I would suggest that a plug that provides intermitent signals,due to it being 'wobbly' is a very real pita.
If your competent at soldering go get one off a car in the breakers and see how that works out..
 
I suck at soldering. Might try cutting one off with some tails at the scrappy and get some bullet crimp terminals and shrink tubes to join them.

Probably still have change from the £12.95 lol.
 
...QUESTION: For those more experienced with auto electrics than me, how sensitive are the CAN connectors to loose/wobbly connectors...

CAN works with voltage difference between two wires to generate the message: either wires are at low potential (< 2,2V) or at high potential (>2,2V) to set the bit high or low (recessive or dominant in CAN wording). That makes CAN quite robust, electric and noise wise, but of course if the connection is erratic, so will be the signal and therefore the information! Which can lead to a non working system ...

I'd try to fix that wobbling connector (tape, wedge, tie-rap) and see what happens before permanent repair.

BRs, Bernie

If someone here helped You fix -or better, understand- your issue, hit the thanks icon @ bottom right corner, it's free and makes us feel helpy ;-)
 
Quick update.

I crimped the connectors on the plug and got a good secure fitting to no avail.

I put it into my local garage yesterday who are really nice guys. Their Snap On unit wouldn't connect to the body module so they had to say they couldn't help.

They've referred me onto an auto electrical specialist who they rate very highly.

So I'm booked in their for the a week on Friday.

Finger Crossed:rolleyes:
 
Ok so update on all this.

Took it into my local garage, there 6 month old Snap On unit wouldn't connect to the car, neither would their 3 year old Autel so they gave me the car back, no charge. Top blokes.

They put me in touch with an auto electrical specialist. He's verified all the physical can lines are good and the signals are going round as they should.

So we're looking at a software issue now, either the power steering software or the BCM software.

He's saying they can't get the VIN etc off the BCM. He's checked the eProm memeroy contents and they're coming out as gibberish.

Does anyone know if Fiat's eProms are encrypted by any chance?

So he's gone off to speak to EcuTesting who refurbished the power steering unit, and to speak to the local Fiat techs about the BCM.

Can't fault the guy he's determined to sort it. Fourth day he's had the car and he's only charged me for an hour of his time. Top bloke.
 
The CAN bus uses a // topology where every device (module) is connected to TWO wires. Even though different modules are connected to different ports when entering the BCM (body control module), they are internally connected in // before entering the CAN µchip.
So if one of the modules gets shortcut or brings lot of noise on the bus, all the others (on the same branch) will be impacted.

I'd suggest your fellow specialist to disconnect as much CAN as he can (hahaha), but the BCM to OBD one to see if he can retrieve info thru the diagnostic plug. Starting from there and if the test shows good results, I'd reconnect the othe modules one by one to find wich one is faulty. If he still can't read anything with only the BCM CAN-connected, then probably the body computer is at fault ...

EDIT: added drawing

BRs, Bernie

If someone here helped You fix -or better, understand- your issue, hit the thanks icon @ bottom right corner, it's free and makes us feel helpy ;-)
 

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