Citroen C5 Aircross Quiz
Exterior lighting / signalling

Automatic hazard warning light activation function

In this manual: Exterior lighting / signalling
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
~2min read

Performance

The automatic hazard warning light activation function automatically signals:

  • heavy decelerations,
  • impacts (deployment of a pyrotechnic element).

Block diagram: automatic hazard warning light activation function

Allumage automatique des feux de détresse
Automatic hazard warning light activation

Key:

  • triple arrow: multiplexed link,
  • single arrow: wired link.
Conditions d’allumage automatique / d’extinction des feux de

Conditions for automatic activation / deactivation of the hazard warning lights

BY SUDDEN DECELERATION
AUTOMATIC ACTIVATION CONDITIONS DEACTIVATION CONDITIONS
IF brake pedal applied IF hazard warning switch pressed.
AND deceleration greater than or equal to 7 m/s² OR accelerator pedal pressed (in the case of automatic activation by sudden deceleration).
AND speed greater than or equal to 40 km/h OR loss of +BAT (battery disconnected).

BY PYROTECHNIC ELEMENT DEPLOYMENT SIGNAL
AUTOMATIC ACTIVATION CONDITIONS DEACTIVATION CONDITIONS
IF pyrotechnic element deployment signal received from the airbag control unit IF hazard warning switch pressed.
OR ignition key moved from position 0 to + APC

Functional description: automatic hazard warning light activation function

STEP

DETAILS
BY SUDDEN DECELERATION BY PYROTECHNIC ELEMENT DEPLOYMENT
1 The BSI acquires vehicle speed and longitudinal acceleration information broadcast by the ABS control unit on the CAN network. The airbag control unit sends the pyrotechnic element deployment information to the BSI via the VAN CAR 1 network.
2 The BSI determines whether the automatic activation of the hazard warning lights is required.
3 Control of the turn indicators by the BSI.
The BSI controls the turn indicator warning light on the instrument cluster via the VAN CONFORT network.
The BSI controls the buzzer via the VAN CAR 1 network.

Degraded mode

A system fault or loss of the deceleration or speed information does not activate the hazard warning lights and does not affect the operation of the hazard warning lights in manual mode.

If the acceleration information is lost while the hazard warning lights were activated by the automatic function, the lights remain operational until the control is pressed.

In the event of a brake switch fault, the BSI directly controls the turn signal lights.

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