C5 hydractive 3 electrical issue

[Dunkah]

Hi all.....
Got an issue I can’t get to the bottom of, of anyone can offer and advice, information or opinions I’d be very grateful.
The issue is, the rear suspension is far too hard, as if the back is stuck in sports mode.
I’ve been through a few things recently and with the help of a mechanic friend I think I’ve narrowed it down to possibly having not enough voltage to a solenoid on the rear accumulator valve block. Just today we had the block apart expecting to find a sticky valve or something similar. All the valves and solenoid seem free to move so we went on to check the solenoid. With a 12v feed the solenoid does move, I’m not totally sure if it moves enough but it definitely moves. We went on to check the electric feed to the solenoid. With the car running and me hitting the sports switch on and off the feed fluctuated from 0v to 8v. So..... I’m now wondering if it should be 12v and I’ve got an electric issue somewhere. Or...... possibly 8v is correct and my issue is the solenoid not working correctly.
Any information at all on this would be greatly received.
Also if anyone could point me in the direction of a wiring diagram I’d also appreciate that.
Thanks all

[GiveMeABreak]

Have you considered you may need your corner spheres or the rear centre spheres replacing....

[Dunkah]

Hi Marc, yeah that was my first consideration. The centre spheres are the ones responsible for stiffness, (please correct me if I’m wrong) so I did those, absolutely no difference at all. Whilst doing that I discovered that the reservoir tank had a split in it, so I thought possibly that had something to do with it, replaced it and again, absolutely no difference. I do have a pair of corner spheres which I was intending to do but it seems to be nearly impossible to get to them with enough room to get any tools onto them to get the old ones off.

[GiveMeABreak]

Yes in normal suspension mode often referred to as 'Comfort' mode, all 7 spheres (the 4 corners and the 1 front and 2 rear central spheres) are in operation. When sport mode is active, the 3 centre spheres are cut out to provide a firmer ride and stiffer cornering.

Regarding the split in the tank - have a read of my post here for some advisory warnings and some labels:

LDS Tank Bursting Warning Labels

[white exec]

For Hydractive 2 (the predecessor to your H3), the solenoids (electrovalves) receive a 12v supply from the suspension ECU for just 0.5 sec (solenoid pull-in) immediately followed by a continuous 25% duty cycle PWM (a 12v square wave, which when meter-reads as approximately 3v) as solenoid hold-in. This arrangement limits power consumption of the solenoids, and reduces heating of them. NB: They must NOT be fed with continuous 12v, even for test purposes.
Current draw for pull-in is approximately 3A; d.c. resistance of the EV is around 4.5 ohm.

The H2 electrovalves also incorporate a reverse diode, encapsulated in the coil winding. This is there to ensure proper PWM operation, and to protect the ECU from a reverse voltage spike when the EV switches off.

If one of these diodes gives up (not unknown) the EV will not hold in properly, which would leave the suspension in Firm mode. As an insurance measure, it is possible to add an extra diode for each EV externally, either at the EV, or (often more conveniently) at the cable leaving the suspension ECU. The diode should be decently rated, eg 400v 6A to ensure long life. It should also be 'reverse' connected, i.e. diode stripe/band to the +ve supply cable, other end to a good Ground.

Everything above relates to H2. Others here might point up differences with H3, but the systems are very similar.

[Dunkah]

Yes in normal suspension mode often referred to as 'Comfort' mode, all 7 spheres (the 4 corners and the 1 front and 2 rear central spheres) are in operation. When sport mode is active, the 3 centre spheres are cut out to provide a firmer ride and stiffer cornering.

Regarding the split in the tank - have a read of my post here for some advisory warnings and some labels:

LDS Tank Bursting Warning Labels

Thanks Marc, think I’ve already seen that post a while ago. I do have a brand new tank ready to fit but I want to get my current situation resolved before I fit it

[Dunkah]

For Hydractive 2 (the predecessor to your H3), the solenoids (electrovalves) receive a 12v supply from the suspension ECU for just 0.5 sec (solenoid pull-in) immediately followed by a continuous 25% duty cycle PWM (a 12v square wave, which when meter-reads as approximately 3v) as solenoid hold-in. This arrangement limits power consumption of the solenoids, and reduces heating of them. NB: They must NOT be fed with continuous 12v, even for test purposes.
Current draw for pull-in is approximately 3A; d.c. resistance of the EV is around 4.5 ohm.

The H2 electrovalves also incorporate a reverse diode, encapsulated in the coil winding. This is there to ensure proper PWM operation, and to protect the ECU from a reverse voltage spike when the EV switches off.

If one of these diodes gives up (not unknown) the EV will not hold in properly, which would leave the suspension in Firm mode. As an insurance measure, it is possible to add an extra diode for each EV externally, either at the EV, or (often more conveniently) at the cable leaving the suspension ECU. The diode should be decently rated, eg 400v 6A to ensure long life. It should also be 'reverse' connected, i.e. diode stripe/band to the +ve supply cable, other end to a good Ground.

Everything above relates to H2. Others here might point up differences with H3, but the systems are very similar.

Thanks Chris, very useful info.
Don’t suppose you can shed any light on where the diode concerned might be located? Or how to test it?
Thanks

[white exec]

Testing the diode (buried in the sealed EV coil windings) is not a straightforward matter, although Simon (Mandrake) here has written up a procedure for it.

Probably best to check that the diode isn't shorted (unlikely, they usually blow open) by simply checking that the EV clicks when closing and opening.

Given that, just add an external one (to be sure it has a working one), and go from there.

You can also wire in (to the same point tap-in point as the diode) an LED, in series with a 120R resistor connected to Gnd.
The LED will show when the EV is energised (in Soft mode), but coming on brightly for the 0.5sec pull-in, and then dropping back in brightness for the hold-in. By having such LEDs (one for each EV) you can also monitor the action of all the sensors that feed into the Hydractive system: throttle action, steering movement, body movement, etc. The two LEDs can either be dash-fitted, or located somewhere temporary, if just for a brief test. If dash mounted, they can be switched off by a simple switch in the LED ground connection.

[Dunkah]

Testing the diode (buried in the sealed EV coil windings) is not a straightforward matter, although Simon (Mandrake) here has written up a procedure for it.

Probably best to check that the diode isn't shorted (unlikely, they usually blow open) by simply checking that the EV clicks when closing and opening.

Given that, just add an external one (to be sure it has a working one), and go from there.

You can also wire in (to the same point tap-in point as the diode) an LED, in series with a 120R resistor connected to Gnd.
The LED will show when the EV is energised (in Soft mode), but coming on brightly for the 0.5sec pull-in, and then dropping back in brightness for the hold-in. By having such LEDs (one for each EV) you can also monitor the action of all the sensors that feed into the Hydractive system: throttle action, steering movement, body movement, etc. The two LEDs can either be dash-fitted, or located somewhere temporary, if just for a brief test. If dash mounted, they can be switched off by a simple switch in the LED ground connection.

Excellent, I’ll look into that.

[myglaren]

Isn't it this that Brian Pimmer's magic box was supposed to fix?

[Dunkah]

Isn't it this that Brian Pimmer's magic box was supposed to fix?

Tell me more about this magic box........

[white exec]

There were a couple of packaged offerings - another from 'e-crofting' iirc.
Basically, these were just a pair of diodes in a small box/casing. No LEDs were included.

[Dunkah]

There were a couple of packaged offerings - another from 'e-crofting' iirc.
Basically, these were just a pair of diodes in a small box/casing. No LEDs were included.

Interesting.... I’ll look into that. Thanks

[white exec]

This is an info sheet that I ran out in 2016 (for XM, Hydractive 2), showing connection of the additional protection diodes, and suspension LEDs...
↓ Click to enlarge

[Dunkah]

This is an info sheet that I ran out in 2016 (for XM, Hydractive 2), showing connection of the additional protection diodes, and suspension LEDs...
↓ Click to enlarge

Excellent! Thanks for that Chris. Will this still be relevant for hydactive 3?