CITROEN DS series Technical Manual page 28

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The Citroën Guide
and tailgate open sensors) , leaving the electro-valve en-
ergized for the duration of the timeout.
It is important to note that the suspension will switch to
soft mode even with the ignition switch turned off. Early
cars did not have this feature built directly into the com-
puter but used an additional relay and circuits. On those
models, the constantly energized electro-valve can drain
the battery if the doors remain open for a long time.
Starting with the H2 suspension computer (from
ORGA 4860, February 28, 1990) the door sensors are ob-
served by the ECU itself and the operation is enhanced with
a 10-minute timeout period. After this interval, the electro-
valves will always return to the hard, non-energized state.
Changing the state of the ignition switch provokes a
transition to soft mode for a maximum of 30 seconds;
reaching a vehicle speed of 30 km/h will cancel this mode
prematurely. When the ignition is turned on, the ECU also
runs a self-test diagnostic sequence lasting three seconds.
When the suspension selector switch is set to the
Sport setting, all sensor inputs except for the vehicle speed
sensor are ignored. Below 30 km/h the car stays in soft
mode and switches to permanent hard mode above this
speed. The suspension status light in the instrument
panel has two functions:
U when the ignition switch is turned on and the suspen-
sion set to Comfort, it will light up for the duration of
the ECU self test. If the computer detects any mal-
function in the course of this test, the light will flicker
one or more times during this period;
U when the suspension is set to Sport, the status light
will remain lit to inform the driver of the setting cho-
sen. The status light actually lights up or extinguishes
only when the suspension rules have been changed in
response to the mode select switch. This takes a short
while because the internal timeouts are reset and
some of the sensors are recalibrated. Because of this
the light changing state is slightly delayed from the
mode switch changing state.
Suspension: Hydractive I 28