Hazard Warning Lamps: Description and Operation

GF82.10-P-3080CE Substitute Lights and Emergency Lights Actuation, Function
MODEL 204.0 /2 as of model year 2009 /YoM 08
MODEL 204.3
MODEL 204.9

Function requirements, general
^ Circuit 15 ON
The status of circuit 15 is sent by the electronic ignition lock control unit (N73) over the interior CAN (CAN B).

Backup/emergency lights actuation, general
The backup/emergency lights actuation ensures the minimum exterior lighting if the event of failure of individual system components of vehicle exterior illumination.
The substitute/emergency light actuation consists of the following subfunctions:
^ Function sequence for substitute lamp actuation
^ Function sequence, emergency lights actuation

Function sequence for substitute lamp actuation
The function of all vehicle exterior light sources is checked. If certain light sources fail, their function is simulated by actuating other light sources, with pulse width modulation if necessary.
In such an instance, flashing functions have priority over steady light.
An active automatic lamp substitution function is communicated to the instrument cluster (A1) from the front SAM control unit with fuse and relay module (N10/1) or from the rear SAM control unit with fuse and relay module (N10/2) via the interior CAN.
In the travel distance display (A1p7) (model 204.0/2/9 (except 204.077/277/377) without code (442) Comfort multifunction steering wheel) or in the multifunction display (A1p13) (with code (442) Comfort multifunction steering wheel, model 204.077/277/377) of the instrument cluster, the "substitute lights active" message is shown.
The scope of the substitute lamp actuation is country-specific.





Function sequence, emergency lights actuation
The aim of the emergency lights actuation is to prevent a complete failure of the vehicle outside lights due to a processor failure or due to the failure of the interior CAN.
To this end, both the front SAM control unit and the rear SAM control unit have separate hardware, which guarantees the emergency light function.
Should the interior CAN, the front SAM control unit or the rear SAM control unit fail, the front standing lights and the low beams will be activated within t < 3 s by the separate hardware in the front SAM control unit. The standing lights and - depending on status of circuit 54 - the brake lights will also be activated by the separate hardware in the rear SAM control unit.