C5 X7 no power steering

[the-termin8r]

That's what confuses me the most, the pipe diagram only shows the pipes and fittings. It makes no mention of any electronics. Not in the parts list nor the diagram.

[wurlycorner]

Blimey, yep. That’s really odd - it doesn’t even split the pipes down at all!
It’s sits in (one of the pipes within) item 1. Roughly at the location shown with item 72.

[the-termin8r]

What's your RPO? That might have slightly different documentation (I've been using my own one up to now) but I'm not hopeful. I also couldn't find anything that alludes to a sensor in any of the disassembly procedures. If that other user hadn't posted the same issue I might have guessed that it could be a previous owner messing with something, but I don't know why they would. Does the X7 share a rack with the C6? Might be worth a look on the C6 owners' forum if it does.

[wurlycorner]

So far, complete fail today - because the damn thing is working absolutely fine, for the first time in months!

I decided I’d start the day by hooking up the Thinkdiag, ensuring the brake master reservoir pressure was drained (pump the brake with engine off) and any possible residual pressure in the power steering system was also dead (turn the steering with engine off) and then start the car monitoring live data while screen recording. I was interested to see if the master cylinder pressure reading etc changed state as things pumped up (it didn’t - which either indicates a fault with a sensor, or it’s not used and always relies on a substituted value?)
Below for your viewing delight, approx 17 mins of me faffing around with the car stationary and then going for a drive, including stop/starting the engine a couple of times to try and get it to ‘fault’ again. No joy - working absolutely fine.
Utterly maddening because I’ve done nothing to fix anything.

[the-termin8r]

That might point to an iffy connector whether it be corrosion or a loose pin or something else because you were unplugging them yesterday.

[wurlycorner]

Yep, but I saw nothing wrong with any of them on inspection and I tried wiggling and pulling on them all while resistance checking etc and… nada.
This is literally the worst outcome of fault finding. Don’t find anything but then a fault disappears. You know it will come back and are in limbo until then.

Also it wouldn’t explain the intermittent no comm faults that the CSS ECU had at one point yesterday (I didn’t disturb any of the CAN network).

Also worth nothing from that footage that the steering angle, steering wheel speed, brake switch position etc all don’t change either (before I go for a drive I am sat there twiddling the wheel and going on/off brakes etc) - so obviously also not used on this particular installation?

[the-termin8r]

Hmm, could it be a damaged loom? Do you see it go around any sharp bends where it might chafe? Any evidence of past or present fluid leaks? I know some German cars will leak oil on a loom and then the oil will travel up the loom because of surface tension and vibrations until it floods the connector on the other end and shorts all the pins.

Regarding the steering and brake data readout, have you verified with Diagbox as well that the data indeed isn't being sent instead of the Thinkdiag potentially giving false readings?

[wurlycorner]

No evidence of leaks anywhere (it all looks good) nor even any excessive corrosion.
No evidence of damaged loom.

However, I have just started visual inspection around the fuse box/ECUs (did not get as far as this yesterday, so didn’t disturb anything here) and I do not like what I am finding…

Definite pinched wire there (the white one - difficult to photograph) and the yellow one also looks maybe a bit dodgy.

Rob, would you mind taking the cover off yours and sending a few pics please?

The way the loom and earths are run next to it on the inner wing.

The general loom layout and arrangement (including this shot towards under the passenger side headlight, where you can see routing and I have a fir tree tie wrap not attached to the chassis)

Is this a splice in that loom (blob on the grey and red wire) and is it original?

And do you have this random lot of 5 wires casually hanging out down the back of the ECUs not connected to anything but running into a bunch of insulating tape?

[wurlycorner]

That pinched white wire definitely goes to the CSS.
There’s also signs of water ingress at some point, onto the CSS (though I can’t see any notable evidence at the connector end).

There is an entire connector , unused and left open/not sealed apparently from factory, which I don’t think is good practice?

The white wire with the bad kink in it, is 7842 (probably E).

Not shown on the colour schematic and drawings you put up last night Rob, but on the previous larger schematic that included all the suspension stuff as well, 7842E is shown as linking the CSS, BSI and suspension ECU. That may have something to do with ‘wake up’ or comm (even though it isn’t the CAN wires)?

The wiring schematic and diagram says one of the 48 way connectors at the CSS ECU is black (NR) and the other Brown (MR) I think? But all are black on mine - they are in the photo that Kees helpfully posted up of his, also.

Showers/poor light stopped play today.
I think tomorrow I will bell everything out from the ECU like I intended and cut/re-splice that white wire where it’s been pinched/bent.

[the-termin8r]

Jesus Christ that hurt to see. I'll get some images tomorrow during my lunch break if weather permits, if not I'll get them first chance I get. I'm hoping mine looks nothing like that.

[wurlycorner]

Thanks Rob.
Unfortunately modern Citroen wiring does look like that a lot - though I am very sure this lot has been out at some point before and not put back in on original alignment etc.

[the-termin8r]

That looks like it's been messed with. Surely there shouldn't be that many conductors not inside a sheath? None of the electrical tape is filling me with confidence either.

[wurlycorner]

Oh Rob… you’ve clearly not delved into factory multiplex Citroen wiring much… bless you - Such sweet innocence!

(They all look s**t with bare bunches of wires with no restraint, sheath or conduit!)

[the-termin8r]

I take my electronic monstrosities in the industrial variety. Thankfully I don't do much in the way of cars, but I've seen my fair share of horrors. Don't ever eat dispensed ice cream. Mind you, with the stuff I've seen, I'm starting to question the whole food industry. LOL

[the-termin8r]

Ok, I've just had a look. I also have the mysterious conductors ending in electrical tape. I have the unpopulated connector on the CSS and all connectors are black. I'm not sure if I have the bodged blue electrical tape. Everything was in there quite snugly and I didn't want to disturb it too much.