Citroen C5 Aircross Quiz
Suspension

After-sales operations

In this manual: Suspension
AAS - Parking Aid — 8Owner's Manual Citroën C5 II — 139Citroen C5 Aircross (2017- 2024) - Owner's Manual — 143Audio system — 14Overspeed control — 7Multifunction display — 4Driver information instrument cluster — 20Navigation assistance — 8Intruder alarm — 7Mechanical specifications — 9Power supply — 8Electrical equipment — 13Lighting and electrical equipment — 3Immobiliser — 4Sunroof — 10Exterior lighting / signalling — 38Multiplexing — 7Air conditioning — 7Body — 6General specifications — 9Automatic gearbox control — 3Exterior mirrors — 10Airbags — 5Defrost — 6Underinflation — 6Interior lighting — 4Wipers / Washers — 6Window lifters — 11Cooling — 8Opening management — 7Cruise control — 5Suspension — 4Grip management — 1Paint — 2Exterior lighting control — 1Indicators (turn signals) — 1Automatic lighting systems - General recommendations — 1Wiper control — 1Special position of the front wipers — 1
~6min read

DEPRESSURISING THE HYDRAULIC CIRCUIT

Warning: There is residual pressure in the low position, so the hydraulic circuit cannot be worked on without depressurising it first.

Any work on the hydraulic circuit requires depressurising the hydraulic circuit.

Methods for depressurising the hydraulic circuit (vehicle must be in the low position):

  • a command using the diagnostic tool depressurises each suspension circuit by forcing the exhaust solenoid valves open,
  • opening the depressurisation screws brings each suspension circuit to atmospheric pressure.

REPLACING AN INTEGRATED HYDRAULIC-ELECTRONIC UNIT

After replacing an integrated hydraulic-electronic unit, perform the following operations:

  • activate identification of the steering wheel angle sensor type,
  • adjust the vehicle height,
  • code the suspension functions.

TOPPING UP THE HYDRAULIC FLUID

Warning: LDS (Liquid Direction Suspension) fluid is not miscible with previous hydraulic fluids

Check and top up the hydraulic fluid with the vehicle in the low position.

If the level is below the minimum level, add 1 litre of hydraulic fluid.

The minimum hydraulic fluid level is the same for Hydractive 3 and Hydractive 3+ suspension.

LEARNING REFERENCE HEIGHTS

After any work on the height sensors or the suspension control unit, perform a reference height learning procedure to accurately set the vehicle height.

The vehicle must be in running order: empty, with all fluids topped up.

FAULT READING

A fault is indicated by 4 warning lights on the instrument cluster or by a specific message on the multifunction display (depending on equipment).

The following faults can be read using the diagnostic tool:

  • low battery voltage,
  • high battery voltage,
  • +APC input missing at the suspension control unit,
  • Hydractive 3+ solenoid valves faulty,
  • front raise solenoid valve faulty,
  • front lower solenoid valve faulty,
  • rear raise solenoid valve faulty,
  • rear lower solenoid valve faulty,
  • pump motor assembly faulty,
  • steering wheel angle sensor faulty,
  • no communication with the ABS control unit,
  • invalid data from the ABS control unit,
  • front body height sensor low fault (open circuit, short to ground),
  • front body height sensor high fault (short to +12 V),
  • rear body height sensor low fault (open circuit, short to ground),
  • rear body height sensor high fault (short to +12 V),
  • invalid data from front body height sensor,
  • invalid data from rear body height sensor,
  • no communication with the engine control unit,
  • invalid data from the engine control unit,
  • no communication with the intelligent power distribution module,
  • invalid data from the intelligent power distribution module,
  • height push button faulty,
  • suspension control unit coding not performed,
  • suspension control unit faulty,
  • CAN network communication faulty.

READING PARAMETERS

The following parameters can be read using the diagnostic tool:

READING PARAMETERS

DEFINITION
Front travel Real-time reading of front suspension travel under load
Front travel speed Real-time reading of front suspension travel speed under load
Lateral acceleration Measurable only while driving
Engine speed Measurable only while driving
Steering wheel speed Instantaneous rotation speed of the steering wheel
Steering wheel angle Instantaneous rotation angle of the steering wheel
Roll sportiness Driving sportiness percentage, measurable only while driving
Bounce sportiness Driving sportiness percentage, measurable only while driving
Pitch sportiness Driving sportiness percentage, measurable only while driving
Hydractive 3+ status Hydractive 3+ active or inactive
Throttle plate speed Accelerator pedal press and release speed
Firm / soft transition cause Reading of the parameter for transition from soft to firm suspension
Road condition Reading of the road condition calculated by the suspension control unit
Height correction status Reading of a correction in progress
Door states Reading of the door and trunk states
Door states Target vehicle height to reach (front)
Rear target Target vehicle height to reach (rear)
Filtered front height Instantaneous actual front vehicle height
Filtered rear height Instantaneous actual rear vehicle height
Programmed front reference height Front height programmed into the control unit by the technician, used as the reference for calculating vehicle height
Programmed rear reference height Rear height programmed into the control unit by the technician, used as the reference for calculating vehicle height
Initial front reference height Front height programmed into the control unit
Initial rear reference height Rear height programmed into the control unit
Brake status Reading of the brake pedal activation status
Height push button Reading of the height push button position
+APC Presence or absence of +APC at the suspension control unit
Battery voltage Reading of battery voltage
5 V voltage Presence or absence of power supply to the front and rear height sensors
Longitudinal acceleration Instantaneous reading of the longitudinal acceleration of the vehicle, measurable only while driving
Headlamp levelling setpoint Instantaneous reading of the headlamp levelling setpoint of the dynamic headlamp levelling correctors

ACTUATOR TEST

The actuator tests that can be performed with the diagnostic tool are as follows:

  • Hydractive 3+ regulator solenoid valve, front axle,
  • Hydractive 3+ regulator solenoid valve, rear axle,
  • front raise solenoid valve,
  • rear raise solenoid valve,
  • front lower solenoid valve,
  • rear lower solenoid valve,
  • pump unit electric motor,
  • dynamic headlamp levelling correctors

CODING

The coding operations to be performed are as follows:

  • steering wheel angle sensor type learning,
  • reference height learning,
  • Activation of the functions fitted to the suspension.

DEGRADED MODES

The table summarises the functions performed in degraded mode.

DEGRADATION FUNCTION PERFORMED

Automatic height correction mode
Loss of power supply Height corrections are disabled
Suspension control unit failure Height corrections are disabled
Loss of height information on one axle Height corrections on this axle are disabled
Pump motor failure Raising corrections are disabled
Solenoid valve failure The correction on the corresponding axle and in the corresponding direction is disabled
Door opening frequency too high The correction on the corresponding axle and in the corresponding direction is disabled

Speed-dependent height correction mode
Loss of vehicle speed information The default height is road height
Loss of height information on one axle Corrections are disabled on both axles

Road-condition-dependent height correction mode
Loss of rough road information The function is removed

Manual correction mode
Pump unit motor failure Road, off-road, high and low heights are not allowed
Solenoid valve failure Road, off-road, high and low heights are not allowed
Loss of height information on one axle The function is disabled
Loss of height button information The default height is normal height

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A quick Citroen C5 Aircross quiz: every answer comes with an explanation and a link to the manual page.