Activa V6 -98

[xantia_v6]

I was using my phone when I made the last post. I just checked the VN05 data sheet and the chip has a status output that indicates open-circuit and over-temperature conditions.

I don't have reference waveforms, but suggest that you use the equivalent pins for the rear electrovalve circuit as your reference. I would also consider the possibility that your replaced VN05 is faulty.

[white exec]

. . . since the signal comes on for a second every 30s . . .

That sounds as if the device is going into shutdown (thermal overload?), and then briefly opening up again.
Try running it with a reduced and known load (eg 15R resistor, or 12v 10W bulb) and see how it copes with that.
There is a good VN05 data sheet available online - I think on the alldatasheets site.

[xantia_v6]

The 30 second shutdown is the error-response of the ECU software and is normally seen when an EV is unplugged, or a diode faulty, although it would also be triggered by thermal shudown of a VN05. I think that it is triggered by an unexpected pulse on the VN05 status line.

[HanaAna]

Comparing the waveforms between rear and front is not possible because there is no waveform in the rear. Due to fault condition in front I reckon. When I placed 100ohm5W resistor to act as EV I could barely see the waveform in oscilloscope, voltage was so small.

"The 30 second shutdown is the error-response of the ECU software and is normally seen when an EV is unplugged, or a diode faulty, although it would also be triggered by thermal shudown of a VN05. I think that it is triggered by an unexpected pulse on the VN05 status line."

I've been wondering what kind of criteria ecu uses to determine that there is "permanent fault front EV". Unexpected pulse in status-line makes sense. I'll try to scope input and status-lines. The two more difficult to get ones

Bad VN05N or bad soldering. Or both

[xantia_v6]

It is a while since I looked inside a hydractive ECU, but maybe the circuit relies on through-hole-plating on the VN05 holes, and maybe the plating was damaged during removal of the old device, so requires the device to now be soldered on both sides of the PCB?

[HanaAna]

Yes that's correct. Once I noticed that, I took the PCB to a professional guy. Who gave me some serious lecturing of my work He made big effort to fix it but because he wasn't able to test it... it's almost likely that he missed some connection. Even though he told that he measured every line both sides. And now it's almost impossible to fix input and status legs of VN05N on the upper side of the panel. I'm waiting for next week cause then I might have a possibility to get another Activa suspension ecu. Fingers crossed!

[HanaAna]

I did get replacement suspension ecu!! Firmly in SOFT-mode Have to admit that I kind of gave up with my original ecu, but sometimes it's better to accept ones personal limitations
Next thing to do is to replace six spheres(H2, Activa, reserve). Already arrived.

[white exec]

Firmly in Soft mode? The mind boggles!
The ECUs are not the easiest things to troubleshoot.
Glad it's working now.
Make sure you fit the additional diodes, as they provide proper working and VN05 protection in the event of the small EV internal diodes failing. It's a recommended preventative measure.

[HanaAna]

This ecu came from France, obviously professional, because diodes were already there. Very nice job!

[white exec]

Good news.