C5 (X7) 3.0HDI - suspension pump brushes and height sensors

[Jay-Bruce]

I've found some brand new C5 mk1 BHI modules on eBay, I'm wondering could I just buy one of them and transfer my pump's ECU across onto it?

[Hell Razor5543]

Probably not, as the motor connectors are almost certainly different. As far as I know the BHi unit has a total of three connectors; power connector, 'trigger' connector, and valve control connector. When I was looking (on ebay) for a replacement BHi for my C5 I found several, but with various designs of power connectors. I was fortunate in finding a similar age C5 at the scrapyard. The motor was slightly different, but the motor connectors were the same (so I did not have to worry about chopping around the plugs).

[GiveMeABreak]

I don't believe this will work Jay. The MK I C5 has an early version of the Hydraulic system and specifically, the BHI is different and won't have the same number of valves and ports I suspect, being that the X7 has 7 spheres.

... ^ and remember, James's C5 is a MK I Facelift (MK II), so again will not be the same as that for an X7.

[MGmike]

I've found some brand new C5 mk1 BHI modules on eBay, I'm wondering could I just buy one of them and transfer my pump's ECU across onto it?

As Hell Razor (James) mentions there are differences in how the motor connections are presented on the side of the motor and the connectors may well be different. On the early C5's the module on the side of the motor is sealed to the motor body with a mastic substance, where as the later X7 and C6 have a separate module attached to the motor body by a screw. Is their function the same... well, yes but how they deliver that function varies I suspect. Could it be a simple case of making up a fly lead with the correct connectors.. possibly but I've not tried it (yet!).

At worst a new C5 pump would be a source of a new brush holder for your pump (see my post above about a good used one and PM me if you're interested in going that route?).

I don't believe this will work Jay. The MK I C5 has an early version of the Hydraulic system and specifically, the BHI is different and won't have the same number of valves and ports I suspect, being that the X7 has 7 spheres.

Marc, all BHI's have the same number of ports e.g. two, 1 for the front and 1 for the rear, and the same number of valves e.g. 4, 1 each for up and down front and rear. The differences in C5's with H3+, X7's and C6's is in the deployment of an extra regulator in the feed line to the front and rear suspension and, as you correctly said earlier, the BHI ECU and, in some cases, an additional suspension ECU which contains the vehicle specific configuration. I believe (but have not tested) the pump blocks are interchangeable once the ECU is swapped. I also think the motors are interchangeable with suitable connectors (again untested).

[Jay-Bruce]

Parcelforce should bring the used pump I bought via eBay tomorrow, I'll look it over, and make my mind up am if I going with it, or frankensteining together a new C5 Mk.I BHI's pump, motor & valve block with X7 electronics. Worst case, if I've got to desolder the brush holder from the plug carrying module, and solder that on to the new pump, it's still a win. But I'll see what state the used pump is in when it arrives. I might just run with the used pump as is, and if I still have issues and need to revisit the BHI, I can frankenstein something together.

@MGmike, whatever I'm left with after the BHI surgery has your name on it,

[Jay-Bruce]

Latest update on this little saga, today's post brought the pump and the rod ends, the rod ends are a beautiful snug fit over the ball on the sensor arms. I was initially worried that there might have been a bit of slop, but the way those particular rod ends are constructed, there is an internal snap ring that keeps the ball snugly located in the socket. So... The seeming unavailability of the height sensor angular pick up rods, part no 5273.81, is now a solved problem.

And the good news continues with the actual used BHI which I bought as well... Before I fit a used BHI, I wanted to check the condition of the motor paying attention to the carbon dust issue. I was pleasantly surprised to see it looked like this:


...and that was BEFORE cleaning...

After a quick skoosh of brake cleaner it looked like this:


But hot diggety damn, that brake cleaner is cold:


So after the commutator defrosted, I reassembled the motor, transferred the ECU - which can only go one way FYI, and have a "serviced" BHI to install tomorrow when the daylight returns and hopefully the rain goes away. Plan is to fit the pump, hopefully get the vehicle raising, put the vehicle on my two poster, change the four height sensors and make up new links. Then I need to get it on a four-poster or a pit and recalibrate the ride height.

Wish me luck

[Jay-Bruce]

Ladies and gentlemen, allow me to introduce to you the new unofficial citroen part 5273.81-JAY, the "Angular Pickup Link" used on C5 X7 hydractive suspension, C5 X7 / 508 xenon headlight adjustment sensors, and possibly other applications.








PS: I am NOT responsible for the previous welding on the original link in these pictures. I wouldn't have welded this part, and if I did, it'd be a damn sight neater than that is.

[MattBLancs]

I think the award for "playing with thermographic camera" pleasing image of the day goes to you, Jay!

Missed the details of the connecting link ball joints: Discussed here? I'll read back and likely order a set "just in case"

Guess the previous welding would suggest this has been corroded to the point of failure previously, in which case I would let off whoever did it on the basis of trying to get molten steel to stick nicely to iron oxide isn't easy!

[MattBLancs]

Ah, ball joints in page 2, must have just missed it as read earlier on the carbon crud / melted brush holder chat, but missed these being reverse engineered
viewtopic.php?p=774153#p774153

[Jay-Bruce]

OK, This is getting ridiculous now!!!

So I've replaced all four sensors and fitted the homebrew -JAY "anglar pickup rods", fitted the recently acquired BHI, which has the car's own suspension ECU on it, and I'm no further forward. The car won't rise, or even try to run it's pump grrr

So I have loaded up a Virtual Machine of Diagbox 7.62 on to my new (to me) diagnostics tablet, and interrogated the ECU's, long story short there was only one permanant recurring fault code, C1148 - reference heights not programmed. When I try to go through the reference height procedure it fails the programming with an error message which says:

Programming failed. Chech the sensors are correctly fitted, i.e.:
- the linkages are towards the inside
- the sensor colours comply with the following rule
* front left: red.
* front right: yellow.
* rear LH : blue.
* rear RH : green.

When changing over the sensors, I made sure to replace them colour for colour, remove the old green one fit the new green one etc. I have also double checked the positioning and orientation of the sensor, they ARE set with the arms /pushrods inboard, you'll see the inboard rods in these pics:









Remember the car is still sitting on it's sills as the suspension is depressurised for removing the BHI, but it won't repressurise just now, so the ride heights were untypically low., so I thought I'd have a look at the raw data and see what I'm up against, here it gets random, with 4x new sensors I get the following values:
- Front left travel : -094.01 ( -ve what in the actual???)
- Front right travel : 064.95
- Rear left travel : -104.01 ( Again; -ve what in the actual???)
- Rear right travel : 108.94

I find it interesting that it's the two left hand sensors that are negative values, could it be that despite the software saying "the linkages are towards the inside", that on the left I need to have the linkages towards the outside?

I think I need to get the readings from the sensors all positive before it will let me program in the reference heights, then I hope it will let me pressurise the system? I think next steps are to remove the linkage from each of the left sensors and with the tablet hooked up on live data see if I'm getting and change in valuefrom moving the sensor. If I don't get ant change in screen from directly moving the sensor I've got one world of hurt, if I do but it's all negative it's a different world of hurt, but there is maybe a light of hope that I'll move the arms and putting the let linkages to the outside will give me +ve sensor values all round, fingers crossed. In the interim, I'm open to suggestions and any shared wisdom y'all might be able to offer.

[Jay-Bruce]

And... When reviewing my post for typos etc, I noticed that the left pair are pointing up, and the right pair are pointing down, front pair:

Rear pair:


I'm now wondering if these have been manufactured wrong with the arms on the left sensors NOT being inverted where they should be?

[MGmike]

Jay, forget about the programming for now and concentrate on getting the pump running. Your BHI will still have your original settings and I think it should at least try and run the pump. I would put your old height sensors back on if they're still serviceable. Old engineers trick... change one thing at a time and you'll be able to back track if required.

I'm presuming you've checked the fuses (G39?)? Check you have 12v at the pump main connections with the ignition on. Then check what voltage you have on the pump "trigger" wire, I'm guessing it'll be 5 or 12v to make the pump run (I can check one of mine if you need confirmation?). Then you need to check for 12v on the Adaptive ECU and the BHI module connectors. I have had one BHI module fail internally which resulted in the pump not running. If this is the case try the other module you have.

[Jay-Bruce]

I'm at the workshop just now, tapping this out on my phone, so excuse the brevity. No voltage on power connector for motor, not trigger, fuse G39 is ok, having been tested with multimeter.

[MGmike]

Sorry I'm late with this Jay..
The main pump connector should be powered up all the time the ignition is on. You need to go back to the pump relay and confirm if it has power. Once that's confirmed we can start looking at the actuation side of the relay. We'll worry about the trigger later!

[Jay-Bruce]

I've given up for tonight, but before I did, I disconnected the battery, checked all the fuses in the positive terminal, pulled the power module where the jump start terminal and checked the fusible links therein, checked all the full-size fuses on the BSI(?) beside the engine ECU, no joy. And now I'm somewhat despondent.

@Mike, nothing to apologise for - I appreciate the help, and almost feel embarrassed to ask this, but can you give me specifics of where this relay is located, what measurements you'd like me to take etc?