Activa ECU Questions

addo · Unread post by **addo** » 12 Nov 2008, 11:48

Does anyone know how sophisticated the active suspension ECU is?

What I'm wondering, is how much it relies on default tables vs how much it just balances input and output. Based on popular experiences of fault modes, I presume when a feedback (sensor) value is out of range it defaults to some lesser state of operation. Before that threshold is ascertained, though - does it ever "make an educated guess" in its reactions?

The reason I ask, reflects longer term ideas of squeezing all the bits into an estate.

Cheers, Adam.

XantiaMan · Unread post by **XantiaMan** » 12 Nov 2008, 12:42

From what we know it seems the ECU goes into a default like the Engine ECU if a sensor fails or flashes up a fault code. Both Citrojim and myself have noticed a slow-down the the response of the anti-roll function when the steering wheel angle sensor 'fails', so in this case i would say yes, it makes an educated guess.

Unread post by **CitroJim** » 13 Nov 2008, 11:20

There's certainly enough anecdotal evidence to suggest that any fault, even an intermittent one, logged by the Hydractive ECU will cause it to use default values with detriment to comfort and handling response. Every HA ECU DickieG or I have diagnosed have contained faults and the car feels better for them being cleared.

I believe this is done for safety as a duff sensor signal could cause the car to react dangerously and anyone unfortunate enough to have driven an Activa with suspension faults will know they are lethel. I nearly put my first Activa in a ditch because of a mechanical problem on the roll corrector

The steering angle sensor (amongst others) seem to love causing the ECU to log an intermittent fault on a very regular basis and these always clear with a Lexia. Why, we don't know, they just do

HA ECU faults can only be cleared with a Lexia or ELIT and this makes the ownership of one of these if you have an Activa almost essential. In fact, it's a job which is best done as routine preventitive maintenance about once a month or as soon as you notice the roll correction especially is not as sharp as it was.

Koukku · Unread post by **Koukku** » 29 Dec 2008, 12:44

citrojim wrote:HA ECU faults can only be cleared with a Lexia or ELIT and this makes the ownership of one of these if you have an Activa almost essential. In fact, it's a job which is best done as routine preventitive maintenance about once a month or as soon as you notice the roll correction especially is not as sharp as it was.

Are these diagnostic tools expensive? And do you know if MaxiDiag FR704 can clear these faults?

Unread post by **CitroJim** » 29 Dec 2008, 12:59

No, sadly, the only tools we know of will clear them is the Citroen Lexia, the Citroen ELIT or the other Citroen tool that begins with a P (Proaxia?). The Sykes ACR4 will as well I believe.

The problem is that Citroen use it's own protocols for diagnostics and these are in no way OBDII compliant.

Sadly, all the diagnistic testers are very expensive. They do occasionally appear on eBay though but go for a pretty good price. I bought mine with faults and it still set me back a good bit...

It's worth knowing that a Peugeot DIAG2000 can be converted into a Citroen Lexia with a bit of software re-engineering.

If you own an Activa, having access to a Lexia is almost essential...

Quackers · Unread post by **Quackers** » 29 Dec 2008, 16:06

I cannot clear my ECU Logs as the the garage i take mine to could not get the Lexia or the ELIT or another one they had to communicate with the car. Refused blank they said.

Unread post by **CitroJim** » 29 Dec 2008, 17:50

Quackers wrote:Refused blank they said.

Was that on all ECUs Quackers?

If so, then there is a problem with the diagnostic connector itself, either a bent pin or a loss of power to it. It has its own fused supply which is essential to power the Lexia properly.

Have you the 30 or 16 pin diagnostic. let me know which and I'll dig out which fuse it is.

Koukku · Unread post by **Koukku** » 29 Dec 2008, 19:18

Is this the correct Lexia model:
http://www.ecutrade.com/5,lexia-3-citro ... XgodA2KICg

Unread post by **CitroJim** » 29 Dec 2008, 19:35

Koukku wrote:Is this the correct Lexia model:
http://www.ecutrade.com/5,lexia-3-citro ... XgodA2KICg

I'm not sure how compatible these are with the older systems that have the 30 pin diagnostic socket. I believe there is an adaptor available but just how far in you can go, I'm not sure as Lexia 3 is designed very much for post-2001 cars.

You're better off with the older Lexia 2. They are 100% compatible with the Activa.

This website shows a picture of a Lexia 2.

Look for them on eBay from time to time.

addo · Unread post by **addo** » 29 Dec 2008, 20:33

CitroJim wrote:The steering angle sensor (amongst others) seem to love causing the ECU to log an intermittent fault on a very regular basis...

Given that it's exactly the same sensor as in a Hydractive II, does the HA ECU log similar faults?

Quackers - I'm wondering if your garage just doesn't have a compatible tool. The fellow I work with uses one that has to be told it's a D8 era Peugeot 406.

Then it recognises the Airbag, Transmission and Engine ECUs without worry.

Regards, Adam.

Unread post by **CitroJim** » 29 Dec 2008, 21:04

addo wrote:Given that it's exactly the same sensor as in a Hydractive II, does the HA ECU log similar faults?

Absolutely yes Adam, they do.

addo wrote: Quackers - I'm wondering if your garage just doesn't have a compatible tool.

Possibly as my Lexia won't see much of my son's 406. Only the engine ECU if I fool it by telling it the car is a Xantia!

If the Lexia cannot "talk" to an ECU it really does not give any clue as to why, just an anodyne message to say, essentailly, that it cannot communicate with it.

Koukku · Unread post by **Koukku** » 30 Dec 2008, 07:34

Is the fault log cleared if you disconnect the battery?

DickieG · Unread post by **DickieG** » 30 Dec 2008, 07:51

Koukku wrote:Is the fault log cleared if you disconnect the battery?

No it can only be cleared by using a Lexia/Proxia/ELIT.

BTW Sykes ACR4 can't access the Hydractive ECU I'm sorry to say.