My reason for this is simply that I'm fascinted by the extent of difference between the two states and quite enjoy driving the Xantia (that I believe has a nice chassis dynamic) with a firm- yet- hydropneumatic ride with barely noticiable roll, and that there are a few characterisitics of Hydractive 2 that I find less favourable. I ran one XM with Hydractive 1 and found that system to be much more pleasing than H2 in use. I drive both on the motorway and on some hilly, twisty backroads and I find the 'sport' setting of the H2 to be lacking on those roads. Sure, 80-90% of the time it clicks to a suitably firm mode but often it lags at a moment where a constant firm setting would be better. I also find the rear suspension to be much softer than the front that causes a weird disparity in pitch modes that I find unrefined (didn't seem as bad on my Xm with H2 so could be a fault with the xantia but I don't think so).white exec wrote:The suspension ECU is designed to run a built-in diagnostic sequence each time the IGN switch is turned on. I am guessing that it expects to see the car at rest, and maybe zero input from the various sensors. In the main, you might get away with all this, because most of the external checks done by the ECU are simply for continuity, presence and resistance of the sensors and EVs.
Still not sure why you would want an "always firm" setting, unless just for experimental purposes.
Having now driven it with the modified system it is working well - on 'firm plus' mode it's like driving an early XM in sport mode but with the nippier and more trim handling than on my 2 XMs.
Anyway, this is all just a personal bit of enthusiasm for the systems.
More pressing matter is that the pedal sensor is still a problem. I spent a bit more time checking the resistances at the 3 pins at the black ECU plug. The resistences measured at pins 3,4 and 12 at the ECU were: N12-N3 3K9 ohm, N12-N4 1K9 ohm and between N4-N3 5K6 ohm. These all seemed a bit low but the voltage supplied from the ecu is 4.7v again, a bit lower than the 5v expected.
The spare pedal sensor I have tested resistances of: 4K2, 2K4 and 6K3 respective to the above, all much closer to the right spec. I tested the pedal current sensor at its plug and it checked out with the same values as found at the ECU so I don't think there's anything being lost somewhere in between the sensor and the ECU (according to one diagram I have there's a big grey multi connector in the dashboard somewhere the sensor wires go through but don't know where) Anyway I swapped the sensor for the spare one with 'better' resistance but to no avail, it still doesn't activate the ecu. One observation was that the pedal sensor temporarily came back to life again after a good 7 miles and then after a while went back to inactive - this is something I think I've seen a couple of times now I wonder why it's occasionally working regardless of which of the two sensors is fitted.
Hydractive still working with all other sensors, steering, brake pressure, body movement, changes between the normal and sport setting (seperate from the additional switch I fitted)
I need a LEXIA!
Jim, I think I'm at such a dead end on this pedal sensor problem I would actually drive all the way to yours just to hook it up!Graeme, you may be best off getting diagnosis via an ELIT Machine... Never known mine to yet fail to read any of the older ECUs... If you are ever down this way call in... Many Clone Lexias seem a bit 'iffy' on early S1s... Mine is...
Jim, this is basically what happens when I press the 'new' additional sport switch on mine now - it cuts the power to the ECU - but not the constant 12v feed - so the ECU acts as though you stopped the engine. Keep driving, or stationary and after the 30 sec it clonks into stiff mode and the hydractive lamp comes on. If I press the switch again it immediately goes back to normal modes. The doors open puts it in soft mode regardless of any switch.Only way I know how to get hard is to stop the engine and wait 30s for the ECU to switch as it goes to sleep...
I just don't quite get this pedal sensor thing though, it's getting voltage, it's sending it back to the ECU, the resistances and continuity are all accounted for...
I also got an LHM leak
The rubber return pipe from the top of the front hydractive firmness regulator joins the main return from the pressure regulator in a T. This had split and was oozing out. It steadily got worse until it was now syphoning LHM out from the tank.
A rubber hose right behind the radiator for 23 years that's so much lower than the tank is trouble!
