Component Description For Trailer Recognition Control Unit - GF31.19-P-4050GR
MODEL 166 up to model year 2016 with CODE 550 (Trailer coupling)
Shows model 166.0
Location
The trailer recognition control unit is located on the right in the trunk.
Task
The trailer recognition control unit has the following tasks:
- Reading in of sensors and signals
- Evaluation of input factors
- Trailer recognition
- Monitoring the ball neck lock
- Actuation of the trailer lighting
- Lamp failure indicator
- Emergency light function
- Consumer shutoff
Reading in of sensors and signals
The input factors are read in via the following connections:
- Direct line
- Interior CAN (CAN B)
Direct line
The signals from the following components are read via direct lines:
- Trailer hitch release (A63) (except CODE 494 (USA version))
- Trailer hitch release switch (S62/24) (except CODE 494 (USA version))
- Trailer hitch lock switch (S142) (except CODE 494 (USA version))
Interior CAN
The signals are read in by the trailer recognition control unit via the interior CAN.
The functions that use these signals are described in the individual function descriptions (see the appropriate block diagram or function schematic).
Evaluation of input factors
The input factors are evaluated by the microprocessor and the corresponding components are actuated.
Trailer recognition
The trailer recognition control unit uses current monitoring of the outputs "left taillight", "right taillight", "left turn signal light" and "right turn signal light" to recognize whether the trailer supply line is inserted or not. If one of the two loads is detected, the trailer is deemed to have been recognized. This status is sent via the interior CAN.
Monitoring the ball neck lock
The trailer recognition control unit monitors the correct seating of the mechanically-hinged ball neck. To this end, the status of the trailer hitch lock switch (except CODE 494 (USA version)) is read in directly.
If the ball neck is not located in a correct position, this is displayed by the flashing of a light-emitting diode (LED) in the trailer hitch lock (except CODE 494 (USA version)) (in trunk at left).
At circuit 15 ON a corresponding signal is also sent over the interior CAN to the instrument cluster (A1). A warning message appears in the multifunction display (A1p13) of the instrument cluster.
Actuation of the trailer lighting
The trailer recognition control unit actuates the following trailer components through the trailer socket (X58) (except CODE 460 (Canada version) and except CODE 494 (USA version)) or the 7-pin trailer socket (X58/11) (with CODE 460 (Canada version) or CODE 494 (USA version)):
- Taillights and license plate lamp
- Turn signal lamp
- Brake lights, flashing brake lights
- Rear fog light (except CODE 460 (Canada version) and except CODE 494 (USA version))
- Backup lamp
Upon requirement of the flashing brake lights, the SAM control unit sends (N10) the time period of the dark phase of the brake lights. The trailer recognition control unit cancels brake light actuation for the duration of this time.
Lamp failure indicator
The trailer recognition control unit monitors the function of the lights on the trailer. However, only faults in the general lamp path are recognized. If a failure is detected the trailer recognition control unit sends a corresponding signal over the interior CAN.
Trailer lighting in LED version:
The minimum current for each lamp path must be I = 50 mA for reliable lamp failure detection.
When this minimum current is undershot, a fault message appears in the multifunction display of the instrument cluster although the trailer lighting is functioning correctly (only with LED turn signals lights).
Emergency light function
| Trailer recognition control unit wiring diagram | PE31.19-P-2101-97NAA |