C5 X7 no power steering

[the-termin8r]

If that's the behaviour you're getting then the battery is probably knackered, kind of amazed it took this long for the car to reject it given how picky C5s are about batteries.

[the-termin8r]

Back on the topic of batteries, I think I got quite lucky. I found a pair of generic clamps on Amazon. They're close enough and will fit with some bodging. The generic clamps don't have the same hole size "order" so I had to re-bore them to all be 8mm. The hole alignment also isn't great, so I had to downgrade to 6mm bolts (my manager at work recommended going to brass bolts if shrinking the size). The generic clamp also isn't quite as tall as the stock one, but it comes with an offset shim that sorts it out. However, using the offset shim means you have to break off the small retention tab opposite the clip on the fuse box where the original clamp sits (it will make sense when you look at it). I haven't fitted it to the car yet, but I'm reasonably confident it will work.

Summary of bodging:
- Re-bore the three mounting holes on the clamp and shim to 8mm
- Cut small retention tab off of fuse box
- Fit shim in hole, it will be quite snug. Watch the orientation, as the holes are slightly offset in the XY plane.
- Replace the stock screws with brass screws. M6x15mm with a 11x11mm square head that's 3mm thick.
- Stick some washers on before tightening the lock nuts on the other side
- Job done?

[wurlycorner]

Updates on the power steering issue from me… I haven’t yet had time to investigate it further, but in amongst the shenanigans changing the alternator (other post) I started the car up and moved around with the aux belt removed.
This confirmed two things:
1. I in fact DO have power steering working (when the aux belt is fitted) because it was the most heavy thing ever to try and steer with the pump not running (much heavier than after the power steering problem appeared) - so I suspect this means it must be stuck in ‘minimum assist’, rather than not functioning at all.
2. Operating the power steering with the power steering pump not running, is not a great idea. It results in the system shoving all the LDS in the steering circuit back into the LDS tank on the return side, not siphoning anything back through the non running pump on the supply side - and if you also have the suspension set to low… this means the tank isn’t big enough and you get a nice overflow of fluid

As for the battery, it did finally recharge after putting the ctek on it for a second time and leaving it for over 24 hours. For a good quality battery that’s only a couple of months old though, it is definitely not in full health.

I refitted it to get the car running again after the alternator change and will get back to investigating the power steering fault (and doing a parasitic drain test to confirm there’s not a separate problem there as well) shortly, before I think of taking the battery back under warranty.

[the-termin8r]

The power steering issue could be with 7111 from the schematics which is the proportional electrovalve. That might have gone on strike.

[wurlycorner]

Yep, that is my first port of call when I get under it next.
Unfortunately I don't know what 'good' looks like for that component (in terms of resistance test, input signal etc.) and there are no functional tests or live data reads *at all* in the ECU that relate to power steering, so it's fault finding by first principles and reverse engineering...

[the-termin8r]

Might be worth a check under the BSI for actuator tests. They're not all logically positioned as you'd expect.

[wurlycorner]

I think I looked through all the possible suspects (suspension, engine, BSI, CSS etc ECUs) and found nothing, but will re-check when I get on it.
It’s the CSS that controls it - minor correction to what I said earlier, there is one related data pid. In the CSS, there is live data for “Variable Power Steering Setting Current”. But that’s just what the ECU is meant to be putting out, not feedback on what is happening and I don’t believe there is a special function/test to allow you to try and manually set a value output for it (which would be helpful so you could then measure at the valve itself, to make sure it’s getting there - only way otherwise would be to fit test equipment to monitor at the valve while driving, comparing to what diagbox is showing on screen at the time, which is far less straightforward!).

I did loads of pics of diagbox during my previous testing, including graphing of live data etc but unfortunately nothing jumped out as being amiss at the time. Perhaps I’ll review it all again off line and see if there is something I missed.

[the-termin8r]

Quickly back the topic of batteries. I finally got around to fitting my new positive clamp, it was more broken than I thought. Having fit it properly, I'd like to amend the procedure a bit.

- Re-bore the three mounting holes on the clamp and shim to 8mm
- Fit shim in hole on the fuse box, slide one end under the retention tab for the original clamp, it will be quite snug. No need to break off the tab like in my trial run. Watch the orientation, as the holes are slightly offset in the XY plane.
- It's going to take a bit of brute force, but you can use the original hardware, no need to change to brass.
- Go for a 5 min drive to reinitialise the TPMS

[wurlycorner]

That was certainly broken.
MOT for the moneypit tomorrow morning - first in my ownership and with lots of the problems I know of not yet addressed (including this power steering fault - and the parasitic drain that will no doubt mean jump start tomorrow morning). Think I’ve addressed everything needed for MOT though, but we shall see…

[the-termin8r]

May the force be with you.

[the-termin8r]

How'd it go?

[wurlycorner]

Passed, just advisories for tyre wear on edge of the front tyres (a hangover from before I sorted the track rod end one side and lower arm and FRIP joint, the other). I spotted a few other little things underneath the back and the tester noticed the power steering was working but heavy - not an advisory.
Needed a jump start to get going first thing, of course. Not looking forward to tracking down that parasitic drain…

[the-termin8r]

Nice. On the topic of starting, with the new clamp fitted, it started on the very first crank this morning. I think that's the fastest start I've ever had in any car. Typically it takes two or three in most cars. It was instant for me this morning.

[wurlycorner]

My X7 is also instant (except when the battery is dead).

[RichardW]

Have you still got that speed input fault code?