Anyone know anything about C2 // C3 racks? - NOW ALSO FAULT FINDING

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Re: Anyone know anything about C2 // C3 racks?

Post by Pug_XUD_KeenAmateur »

myglaren wrote: 24 Mar 2018, 12:35 It surprises me that dinky C2s and 3s would need PAS anyway.
a few years back it would've surprised me, but then I helped daughter sell her Mk1 106D, first car. The amount of people who phoned and weren't interested coz it didnt' have PAS you would not believe!

I pointed out that she's 5ft nowt, it was her first car (I taught her to drive in it, my words were "I'll teach you but you can wreck your own car".. .she never did) and has as much strength as your below-average Wimp; but mostly to deaf ears.

I've noticed since that PAS is a great thing for masking an almost flat tyre; not great for safety.
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Re: Anyone know anything about C2 // C3 racks?

Post by xantia_v6 »

Looking at the information above, you can see that the motor has only 2 connections, so must be a simple motor that has its polarity reversed to give assistance in either direction. It is unlikely to develop a unidirectional fault.

The torque sensor has 2 coils and 3 wires, so is probably some sort of balanced or differential transformer. Any fault is likely stop it working completely.

I therefore think that your fault must be in the ECU, most likely a failure of a driver transistor.

Have you checked that the steering is symmetrical with the motor or supply disconnected, to rule out a mechanical fault?
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Re: Anyone know anything about C2 // C3 racks?

Post by GiveMeABreak »

And I forgot to mention that I’ve heard of several cases of C3 PS issues where the assistance comes and goes; which can be down to a bad earth to the PS unit.

The PS ECU is not on the PS unit itself, but under the battery compartment, I think I mentioned.
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Re: Anyone know anything about C2 // C3 racks?

Post by wurlycorner »

Thanks for the wiring diagrams Marc - no I hadn't asked for them previously, so no reason why you would have known :D (I had assumed there would be one in Haynes).

I'll post the video of live data tonight - as far as I can make out from that data, the ecu is working fine in both directions.

And having tried the steering with the rack motor unplugged, I can confirm it would be a nightmare to drive without power steering! (Completely unreasonably heavy at slow speed).
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Re: Anyone know anything about C2 // C3 racks?

Post by wurlycorner »

Ok so not last night, but now...

Summary of the diagnostics I carried out last weekend.

Global test;
Image

Faults log;
Image
Image
Image
There was more below, but point being nothing to do with the power steering - although the "FC82" is an unknown fault.
Marc are you able to shed any light perhaps?
Image

Started with checking the steering column unit (Com 2000 as I would call it but perhaps it isn't one on the C2) since that showed as a "?" for faults and potentially it had a steering sensor in it, based on C5 setup...;
Image
Proceeding to next step though suggested it communicated fine;
Image
And as you can see, there are no steering angle sensors in that unit, so can't be anything to do with the power steering fault.
FWIW;
Image

Next up live monitoring of the steering in operation...
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Re: Anyone know anything about C2 // C3 racks?

Post by GiveMeABreak »

Ok, so that FC82 code is a fault in communication with the transponder Iain. I don’t have any more info on it at present though.

You’ll normally only have a steering wheel angle sensor if you have ESP on the car for the stability programme.
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Re: Anyone know anything about C2 // C3 racks?

Post by xantia_v6 »

The ECU could be faulty without raising a fault code. You really need to measure the motor current to see if the ECU is driving properly in both directions.
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Re: Anyone know anything about C2 // C3 racks?

Post by wurlycorner »

GiveMeABreak wrote: 29 Mar 2018, 20:12 Ok, so that FC82 code is a fault in communication with the transponder Iain. I don’t have any more info on it at present though.


Thanks - you say "the transponder"... Transponder for what please?
You’ll normally only have a steering wheel angle sensor if you have ESP on the car for the stability programme.


Yeah, my C5 has steering angle sensor but is the LX version (base as they come, so no ESP, no H3+ etc.) so I'd assumed it was just a standard part of the column unit and/or with this car having electric power steering, it would definitely need this sensor.
Having seen the wiring diagrams you kindly posted (which came after I'd done the diagnosis above) obviously it just only seems to rely on the torque sensors built into the rack.
xantia_v6 wrote: 30 Mar 2018, 01:10 The ECU could be faulty without raising a fault code. You really need to measure the motor current to see if the ECU is driving properly in both directions.
Yeah that's what the live monitoring shows, which is why I don't think there's an issue with it - unfortunately haven't been able to post it yet, cause having problems uploading the video, annoyingly :evil:
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Re: Anyone know anything about C2 // C3 racks?

Post by wurlycorner »

Ok photobucket still isn't playing for the video's so have gone for youtube.

First video is the first testing I carried out. On that one, I haven't been helpful by giving any verbal commentary, sorry :oops: but basically I start with wheels straight ahead, turn to the right fully, let go, then turn all the way to left fully, let go, then turn back right (can't remember if I just went to centre or full right)


I couldn't see anything obvious that suggested the system wasn't working the same (or very similar) in both directions. I'm surprised to not see the applied voltage 'reverse' polarity (otherwise I can't understand how the assistance changes direction?) but it could be that the ECU indication only measures 'absolute' vd???

Following that, I went into the power steering ECU to see what that could tell me about how it was configured. It's not obviously helpful info in that regard - these are the two screens you're presented with;
Image
Image

I went into the "Assistance Law" (nb you can't seeminly change it from "Law No.15" to anything else, but can change the settings within that law) and unfortunately it doesn't tell you what current settings it had, just gives you the options you can set it to. So no idea if it was set right or not, but I thought I would run through and make sure I knew they were set correctly - screens in order as I encountered them and left them;
Image
(again, you can't change "normal law" to anything else)
Image
Image
Image
Image
Image
Image

After that I re-tested. This time with helpful commentary :lol:


No difference in feel and no different in indications, from what I can see?

After that I unplugged the two pin electrical connector from the motor (left the sensor connector connected);

Steering felt same in both directions like this.
Last edited by RichardW on 30 Mar 2018, 13:47, edited 1 time in total.
Reason: Fixed the youtube tags - just put the last bit of the youtube URL after the = sign in the youtube tags.
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Re: Anyone know anything about C2 // C3 racks?

Post by wurlycorner »

I should add, not sure how you embed youtube video's to posts on here... On other forums I'm on that use this software, you just dump the youtube URL in the text and it automatically embeds the video. That doesn't work here and adding the 'youtube' switch around it does either... But anyway, the link works and maybe marc or one of the other mods will sort the embedding and tell me where I'm going wrong :)

Incidentally, after the final live test above, the steering ECU did correctly log a fault with the rack;
Image


After all that, I tried clearing the fault log (good practise, since it was full and telling me nothing useful). Total failure at that too :roll:
Image
Image
So I created one. It's really annoying that on the screen where you create one, it asks you to put in the "MILEAGE". Then when you've done that and it gives you the screen to confirm it's created the log, it shows you that it "mileage" means km :roll:
Image
Anyway...
Image
Image
Image

Tried a couple of times, with the same result.
Was able to independently clear the fault in the power steering ECU.

So all in all, not very enlightening, but rather infuriating!
Last edited by wurlycorner on 30 Mar 2018, 16:46, edited 1 time in total.
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Re: Anyone know anything about C2 // C3 racks?

Post by wurlycorner »

Thanks Richard :D

In the last video btw, the thing I don't understand is why the torque sensor doesn't seem to react (and shows a permanent negative effort).
I would have thought that should still operate??? (unless that isn't just a reading from the torque meters, but is an ECU make up based on something like comparison between motor volts and measured torque?)
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Re: Anyone know anything about C2 // C3 racks?

Post by GiveMeABreak »

Re: the youtube links: insert the youtube 'tag' from the editor, paste in the yourtube url - BUT, you need to remove everything to the left of, and including the '=' sign.

The PS ECU is the same on all the C2 range - it is just configured as you have seen for the correct wheel sizes and engine type. The only difference it the actual rack with the higher powered motor on for the heavier cars. So make sure this is right for your engine type and wheel size Iain.

I see there was a fault with the power steering - did you make a note of the actual code before you erased it? That would be helpful for me to investigate...

However, seeing as you had over 500 fault codes - these could be historical and can confuse the current situation, so clearing hem all down, taking it for a spin and re-running the diagnostic would make sense so we can see what is remaining and relevant. I would ignore the code I mentioned in this case (transponder) - that relates to the transponder coil circuitry in the ignition barrel. The control module under the steering wheel (what is sometimes referred to as the Comms unit), handles communication between the transponder signal from the key and the BSI and vice versa. So there may have been an issue at some point in the past and the fault was never cleared (unless of course it returns)!
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Re: Anyone know anything about C2 // C3 racks?

Post by wurlycorner »

Thanks for the update on the transponder.

The power steering ECU settings I've already shown set correctly - as shown in my post.

Like I also said in my post, the power steering fault code was logged after I unplugged the motor as part of final testing, so that's entirely irrelevant/known caused by me. No power steering faults logged before that point.

Also as I said, I tried to erase the fault codes but it's refusing to do that (I'm guessing you haven't got to those parts in the thread and are replying based on the earlier posts, or skim-read the text I put in? :) ) but in any event with no power steering faults logged before but me showing that when I induced one it still recorded it, I can't really see that's going to help in diagnosing unfortunately - much as I do still want to clear the old stuff out!
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Re: Anyone know anything about C2 // C3 racks?

Post by GiveMeABreak »

I think you have a duplicate picture - the ones showing the text "Erasing of the Fault Log....." so should the second one be of where you are creating the zone?

Normally the faults have to be read first before clearing, then it may ask you to turn off the ignition and then turn it on again to complete.

Yes, I was aware of you disconnecting the motor and that it would generate a fault - but was just wondering if there was an actual historical code regarding the steering there out of the 500 or so listed Iain.

You may find that there are a lot of the same faults - recorded each time it occurs, so experiment by selecting the fiorst specific fault, reading it and then erasing it - and see if it gets rid of the rest of the same fault codes. Then do the same for the others. See if that makes a difference.
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Re: Anyone know anything about C2 // C3 racks?

Post by wurlycorner »

Yeah there's a duplicate pic - it should have shown a pic of the screen where I had input the mileage, I'll correct that now. It's not particularly relevant though, I only included it as evidence that after inputting "mileage" (with no km unit shown) it then shows a screen that shows it actually wanted you to use the units of km (nb: there's also then another screen confirming you've created the extra service log, that I didn't even bother to photograph).

No faults logged in the power steering system at all before I started - shown by the global test and by me having scrolled down the 'number of incidences' log and the individual fault log - all 500-odd of them :zzz:

Yes, you have to read the faults first (it gives you a message telling you to, if you haven't, just as it gives you the message that you need to create a service record if you haven't) - both of which I did (otherwise I wouldn't have been able to post the screens I posted where it warns you that it erases all intermittent faults, or the screen where it says it is erasing...)

In the fault log there are tons of duplicate faults occurring and disappearing in very short succession.
There's no way I can see of clearing them individually?
The screenshots I posted earlier:
Display in 'number of occurrences';
Image
Display in an individual fault entry;
Image
No options there to clear the faults?
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