Hydractive strangeness

[white exec]

Series II XM did retain the Hydractive warning/test lamp.
For several years, XM and Xantia shared the same suspension ECU, which was programmed with both cars' algorithms, technician selectable according to the vehicle it is installed in - so I guess that the warning light facility will still be there. John's posts on XM site detail the ECU versions.

[CitroJim]

For several years, XM and Xantia shared the same suspension ECU, which was programmed with both cars' algorithms, technician selectable according to the vehicle it is installed in.

Presumably only on brand new ones as a one-time option Chris? In a similar way that HDi Engine ECUs can be coded to the immobiliser transponder and CPH...

I've not seen the facility to do this when looking at the Hydractive ECUs with Lexia but then I may have missed it...

[white exec]

Jim, Some info here (3pp from Citroen manual) about dual programming of the later H4 ECUs, to cover both XM and Xantia:

http://i1152.photobucket.com/albums/p48 ... 0z12lx.jpg
http://i1152.photobucket.com/albums/p48 ... c6n5wa.jpg
http://i1152.photobucket.com/albums/p48 ... vqpbzo.jpg

[CitroJim]

Thanks Chris, excellent So it looks like it can only be done once then...

In extremis, an XM ECU will work in a Xantia and vice versa but it won't be perfect...

By chopping on an index bar in one of the connectors I've used an Activa Hydractive ECU in an ordinary Hydractive Xantia before now...

[aerodynamica]

I read somewhere that there is also a default set of rules in the ECU that corresponds to the 'Xantia model'. I might have misread this though.

Anyway to confirm, I just went out to start up and observe the car and it is still doing the stuck in soft mode thing and making no reaction to any input except the doors and boot switches. Both front and rear in soft mode and both click off quite the ticket into hard mode after door closed. I had a quick look at the 3 pin connector to the speed sensor (not that this is the cause) and it looked pristine inside. Same with the ECU multi plugs. It's very strange. I think Lexia is the next port of call..

[aerodynamica]

Minor update, I got impatient and took the car out to the garage stood mode all the way until the motorway where it suddenly started to work again albeit really sensitive and lingered in hard mode longer (as though it was taking the speed add maximum)

Anyway went to check the Speedo cable with the Speedo etc out and found the cable isn't spinning. Checked the cable down at the gearbox (can be split there leaving a short cable coming up from the diff) and that's not spinning either. So the drive from the diff is broken in some way. Unplugged the speed sensor to look at it. The Speedo cable cooked from the sensor itself and the sensor is connected to the diff in some way. I have a dreaded feeling something terrible has broken in the gearbox our that the ' box needs to come out to repair a simple drive to the cable

[white exec]

Your post takes a bit of deciphering, Graeme - too much whisky or too much predictive text!!

If the lower end of the speedo cable isn't turning, it could be (I'm guessing) that the speedo drive pinion (which just lifts out when the sensor is released from the gearbox casing) has just stripped its teeth, which may be nylon. Not familiar with this bit on Xantia, but XM is similar.

If speed sensor is haywire, suspension operation will be too, as you say.

[aerodynamica]

Your post takes a bit of deciphering, Graeme - too much whisky or too much predictive text!!

.

hehe ".. I shall be sick as a dog in the morning.."

Yes predictive text as ever! Back home now and on comp.

So, a bit of movement - the speed sensor unplugged

Then out with the smaller speedo drive cable

(that's a 2CV wheel creeping into shot there)

Hope the gearbox doesn't empty half its oil if I remove this!



Anyway enough of my usual photos excess, the speed sensor appeared physically ok but the drive from that pinion you mention is broken



I'm guessing that this nylon pinion is actually not part of the speed sensor. If anyone has access to the service Citroen microfiche type diagrams and could look up this part it might be similar on many models (?) It looks a bit like the square section drive that's snapped would actually pull out from both the pinion and the speed sensor as though it is just a sort of key drive. If it's NFP I might be able to fashion a bit to replace it.

Anyway this explains a good deal of the problem! the hydractive ECU was getting no speed information as the speed sensor was not spinning to give the pulses. It was however electrically ok as it was passing the ECU's test of componenets in circuit since it was connected as normal. This is why it was staying in soft mode all the time, the ECU is happy and thinks the car is stationary. However it doesn't explain why the ecu wasn't responding to the input from the pedal sensor, the only sensor that works below the 30km/h threshold.

I decided in the interim that it was probably better to let it stay in stiff suspension by unplugging the ECU connectors but blimey it's firm! I'll be taking Old Katy in to work tomorrow but might plug them back in as perma soft suspension is maybe better than perma stiff for going across the city..

The speedo not working a week after I had the speedometer etc out to change the bulbs was such a red herring here because it looked like the bulb change was the cause of the speedo stopping working haha well anyway I had the speedo panel out this evening first to check that had'nt been the case prior to the above bits coming out (also to look again at the possible connections needed for the reinstatement of the hydractive lamp in the dashboard) but now it's back in place the bloomin oil temp gauge has stopped working alongside the hydraulic pressure, engine oil and STOP lamps..

[CitroJim]

Two steps forward and one step back Graeme...

That's why when dealing with the instrument panel, always change all bulbs at once so you only have to do it once!

Pleased you have found the basic issue with the hydractive... That's several steps forward...

I just hope you can get the parts you need as Xantias with mechanical speedos and cable drives are very rare... You will note it's very XM-like and XM cables and drives are like the proverbial hen's teeth now and long NFP...

[xantia_v6]

I think that the spindle cog is common with the later electronic speedos, so any BE3 unit should fit, but check the number of teeth.

Also check that the speedo cables spin freely, or you may break another.

[white exec]

Parts look like available, Graeme...

[xantia_v6]

Looking at the diagram and picture again, I think that the broken nylon square is part of the sensor, not the cog. The sensors (with pass-through for the mechanical cable) are commonly available on ebay and perhaps amazon.

[aerodynamica]

Thanks all, and I think you're right - the broken drive is part of the sensor but it's prudent to check the cable is spinning too.
The Speedo needle was a little bit wobbly (+/- 5mph) that made me think it was overly lose inside the cable.
Anyway I got fed up with stiff suspension and it's now back to perma-soft for today as its better fire some of the dreadful roads here that haven't been repaired. It's kind of like a comfort mode with the rear suspension squat being the only bad bit. The body roll isn't bad. Anyway updates to follow! Thanks for all the help so far

[xantia_v6]

If I had to guess at the cause of the problem, I would say that when you refitted the speedometer, the square on the end of the cable did not engage properly, pressing the inner cable into the outer, and causing it to bind, eventually shearing the nylon peg at the sender. It may also have damaged the cable further up.

[aerodynamica]

That's also what I thought but there was a few days where the Speedo was working so I think it was engaged fully.

I've been calling a few places to see about a new cable but need to call into the place to look at the 3 possible cables the guy at AEP found.

I have a new speed sensor on order that hopefullywill arrive tomorrow!