Faulty Hydractive 2 sensor ? - solved

[bernie]

Ive emailed you a copy.

Regards,
Simon

Thanks Simon, but nothing received

Hmmmmmm.

Sent again. Let me know if you don't get it again...

Regards,
Simon

Still nothing Simon, did you get the email I sent on the 25/08?

[bernie]

Simon
I've sent both a pm and email to test

Bernie

[Mandrake]

Taken to PM so we don't clutter up this thread anymore....

[Stempy]

Well I got time over the weekend to have a look at my black plug on the HA2 ECU and found that there is not, and never has been anything connected to pin 11, as there is no wire attached to that position.

So I'm not sure how the suspension knows when the brakes are applied, I can only assume that Citroen, in their wisdom, decided this was unnecessary on the later models.

[CitroJim]

My Activa seems to have one, a black box buried down in the depths of the subframe close to the ARB, but having no apparant physical connection to it, on the drivers side not that far from the height corrector.

I can't say it's in the same position as yours Simon, from your description as there is no way I'd get at it from the wheelarch. Perhaps the Activa is a bit different.

I presume it's an inertia (or g) switch, the contacts closing on heavy deceleration? Or am I confusing this little unit with the sensor that is attached to the ARB to measure lateral acceleration

I'll have a look for a connection to pin 11 next time i'm out playing.

2. How is your LED setup? What resistor value did you put in series, diode, etc?

Once I put a 12v lamp but it´s awkward to leave the lamp anywhere in the panel. A LED would be much nicer!!

Using ordinary 5mm LEDs I find 330 ohms works well and is a reasonable compromise to give fair brilliance on the holding current whist not too badly overloaded during the initial full operating pulse.

[Mandrake]

Hi Guys,

As you know, the Activa and V6 are "special case" models so it could well be that the sensor is in a different location.

My Activa seems to have one, a black box buried down in the depths of the subframe close to the ARB, but having no apparant physical connection to it, on the drivers side not that far from the height corrector.

That sounds like the "body movement" sensor - it's somewhat to the right of the height corrector and clamps onto the rollbar with a familiar clamp, and has an electrical plug - if yours doesnt have this, maybe someone has removed it!!

I can't say it's in the same position as yours Simon, from your description as there is no way I'd get at it from the wheelarch. Perhaps the Activa is a bit different.

Sorry I didnt get a picture of it... but rain was threatening and I was in a hurry. It may well be in a different location on an Activa.

I presume it's an inertia (or g) switch, the contacts closing on heavy deceleration? Or am I confusing this little unit with the sensor that is attached to the ARB to measure lateral acceleration

You're confusing them both.

The body movement sensor (attached to the rollbar) only detects vertical front suspension movements - such as hump back bridges, speed bumps, and imminent suspension bottoming and switches to firm mode. It doesn't detect roll.

The switch I'm talking about connected to pin 11 is a hydraulic pressure switch - it's connected to the front brake supply line between the doseur valve, and the ABS block, and looks like a K shaped 3 way hydraulic union with a plug connected to one end.

Below 35 bars its closed, above 35 bars it goes open circuit.

Regards,
Simon

[Stempy]

I had a good look and mine definitely has the hydraulic pressure switch fitted, but with nothing plugged into it, and as previously mentioned, there is no wire feeding pin 11 of the ECU. Don't know why they would fit a pressure switch then not wire it in, you'd think they would have a blanking plug. Nowt so strange as Citroens.

[CitroJim]

Thanks Simon,

All becomes clear now I've spotted the "K" union in my travels underneath. Thanks for the clarification on the body movement sensor Bit of a senior moment, I was struggling to recall exactly what it did Roll detection on an Activa is purely mechanical, using a height corrector lying on its side..

As long as it's dry tomorrow evening (our summer has gone now, such as it was ) I'll go and take a closer look and see if I have the same as you Stempy. It is difficult to see how the HA system can work correctly if it cannot detect braking