Activa V6 -98

[HanaAna]

Hello everyone!
My first post on this forum I've had my Activa for couple of months now and have fixed all the easy stuff and got it MOT:ed! I've resealed oil pan, changed the o-rings of the hydraulic pump, replaced rubber-hose in Activa pipe-hose in the rear end and I just finished replacing handbrake cables. And I did change cambelt, waterpump and aux belt. All in all I think it is in pretty good shape, 230k km on the clock.
The problem I'm struggling with at the moment is "Permanent fault, front electrovalve". The diode was burned. Now there are diode-fix on the ecu for all three transistors. Well that gave no relief on the fault, so I changed VN05N of the front electrovalve because there were some heat signs on the pcb. I have now another electrovalve in use but nothing seems to help.
I saw Mandrake's hint to replace electrovalve with 100ohm5W resistor to check if ecu and wiring was ok. Tried that today and I still cannot clear the fault with Lexia...
I've seen people reporting exactly the same but none finished the story Maybe that's because it was an unsolved suspension ecu problem afterall?
Do I have any chance to get another activa ecu? Is it different than TCT ecu? Are there any instance specialized to get the ecu fixed? Any ideas?

[xantia_v6]

If the fault is still present with the resistive load replacing the electrovalve, then I think that you need to look more closely at the ECU and wiring.

It would help diagnosis if you could connect an oscilloscope to the electrovalve wires and compare the waveforms. At least try measuring the voltages.

I expect that the V6 and TCT Activate ECUs are identical, or at least similar enough for a test. You could check the part numbers for the ECU and the connecting harness to be certain.

[HanaAna]

If the fault is still present with the resistive load replacing the electrovalve, then I think that you need to look more closely at the ECU and wiring.

It would help diagnosis if you could connect an oscilloscope to the electrovalve wires and compare the waveforms. At least try measuring the voltages.

I expect that the V6 and TCT Activate ECUs are identical, or at least similar enough for a test. You could check the part numbers for the ECU and the connecting harness to be certain.

Activa group at FB told info that all Activa suspension ecus are swapable, X2 needs ecu from X2 I assume... I think that is good news, because availability...

I was measuring pin#2 on white connector and there was no signal, when this short period of signal is omitted every 30s. On pin#1, I think thats the front electrovalve (less than 2 Volts, bit low?):

[white exec]

Main suspension EVs should be 12v for 0.5sec 3A (pull-in), followed by approx 3v 0.5A (hold-in). The latter is actually a PWM at 1kHz, which equates to about 3v mean.
d.c. resistance of the EV is stated as approx. 4.8 ohm.

An LED (with resistor) will show the correct operation of the EVs, at the two power levels.

Correctly installed and working diodes are essential to the EVs working properly, installed either at the EV end, or at the ECU connector. Even if the one at the EV is intact and working (and they can fail), it is worth installing a second one (at the ECU connector, for convenience) for protection of the ECUs output stage, and positive solenoid action. 3A 400v is a pretty safe diode spec.

Be careful with choosing suspension ECUs for Xantia. Activa ones may have been a single version, but standard Xantia ECUs were also shared with later XM, and need to be configured into Xantia (or XM) mode.

[HanaAna]

Main suspension EVs should be 12v for 0.5sec 3A (pull-in), followed by approx 3v 0.5A (hold-in). The latter is actually a PWM at 1kHz, which equates to about 3v mean.
d.c. resistance of the EV is stated as approx. 4.8 ohm.

An LED (with resistor) will show the correct operation of the EVs, at the two power levels.

Correctly installed and working diodes are essential to the EVs working properly, installed either at the EV end, or at the ECU connector. Even if the one at the EV is intact and working (and they can fail), it is worth installing a second one (at the ECU connector, for convenience) for protection of the ECUs output stage, and positive solenoid action. 3A 400v is a pretty safe diode spec.

Be careful with choosing suspension ECUs for Xantia. Activa ones may have been a single version, but standard Xantia ECUs were also shared with later XM, and need to be configured into Xantia (or XM) mode.

So it seems that half of the voltage is missing and of course current.... I installed 1N4007 diodes according to some fellow Activavist. Now that I look at the specs, it's 1000V and 1A. So that could mean that the diodes are already dead? At least it's worth getting 3A 400V diodes and see how it goes.

[xantia_v6]

I think that you should check that there is no short-circuit on the wire from the ECU to the front electrovalve.

[HanaAna]

Totally agree with that, and I was checking the wires tonight and they’re ok.
Now I have to put it back together because I need to drive this thing. Hard as a bimmer ;-D

[xantia_v6]

It seems that the ECU is about the only thing left... Maybe there was some collateral damage when the VN05 was changed?

[white exec]

Both 1000V 1A and 400V 3A should be quite adequate for added protection diodes.
Good advice to check the security of the wiring to the EVs.

Caution: do not apply 12v dc directly to an EV, as this can kill the internal diode, and cook the EV solenoid coil. The polarity of the solenoid coil is also marked on its brown connector casing; don't reverse this, as it can cook the internal diode.

[HanaAna]

Good points there. I've started to feel that maybe the ecu is not totally burnt. Just have to systemically go through things. There were some issues when soldering VN05N, but I was rescued by professional...
I was tipped to use resistor as in the pic to measure EV solenoid: (from 007 site)

[white exec]

That test would tell you whether the int diode was working or not.
Worth fitting additional ones, in any case.

[HanaAna]

That test would tell you whether the int diode was working or not.
Worth fitting additional ones, in any case.

Yes exactly. That should also tell if coil is burnt, I guess. If the current rises.

[white exec]

With polarity one way round, both diode and coil should conduct.
With polarity the other way round, diode should not conduct, so current reading will be lower.
The 5? resistor is there to limit current through the diode in the conducting direction - and why 12v mustn't be applied direct to the EV.

[xantia_v6]

You could use the oscilloscope to compare the waveforms on the front and rear VN05s, including the drive waveform and the current sense pin (I think that there is one).

[HanaAna]

You could use the oscilloscope to compare the waveforms on the front and rear VN05s, including the drive waveform and the current sense pin (I think that there is one).

This is something I already tried, nerve wrecking since the signal comes on for a second every 30s and I could't attach the probe to signal leg of VN05N. On the other side tried not to short circuit anything
I wonder what the proper input waveform should look like? Voltage? What's the "current sense pin"?