Component Description For Trailer Recognition Control Unit - GF31.19-P-4050GN
MODEL 166
as of model year 2016
with CODE 550 (Trailer coupling)
MODEL 292
with CODE 550 (Trailer coupling)
Shown on model 166.0
Location
The trailer recognition control unit is located on the right in the trunk.
Tasks
The trailer recognition control unit has the following tasks:
- Reading in of signals
- Evaluation of input factors
- Release, swivel and lock trailer hitch
- Monitoring of ball neck lock
- Trailer recognition
- Trailer consumer actuation
- Lamp failure indicator
- Emergency light function
- Consumer shutoff
Reading in of 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:
- Fully electric trailer hitch swivel unit (A63/2) (except CODE 494 (USA version))
- Fully electric trailer hitch trunk lid/liftgate switch (S142/2) (except CODE 494 (USA version))
- Fully electric driver door switch (S142/3) (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.
Release, swivel and lock trailer hitch
The trailer hitch consists of an electromechanical swivel unit, which can swivel the ball neck together with the trailer socket (X58) (except CODE 460 (Canada version) and except CODE 494 (USA version)). The ball neck can be swiveled in and out using the fully electric trailer hitch trunk lid/liftgate switch or using the fully electric trailer hitch driver door switch (except CODE 494 (USA version)).
The trailer recognition control unit uses a Hall sensor in the fully electric trailer hitch swivel unit (except CODE 494 (USA version)) to detect the current position of the ball neck.
The following components are integrated into the fully electric trailer hitch swivel unit (except CODE 494 (USA version)):
- Hall sensor for detecting position of ball neck
- Swivel motor for swiveling ball neck in and out
- Locking finger for ball neck lock
- Locking finger sensor for monitoring the ball neck lock
Monitoring of ball neck lock
The trailer recognition control unit monitors the correct seating of the electrically swiveling ball neck. To do this, the status of the locking finger sensor in the fully electric trailer hitch swivel unit (except CODE 494 (USA version)) is read-in directly. If the ball neck is not in the correct position, this is indicated by an LED flashing on and off in the fully electric trailer hitch trunk lid/liftgate switch or in the fully electric trailer hitch driver door switch (except CODE 494 (USA version)). 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.
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.
Trailer consumer actuation
The trailer recognition control unit actuates the following trailer components through the trailer socket (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)):
- Brake light
- Rear fog lamp
- Backup lamp
- Turn signal lamp
- Taillight and license plate lamp
Lamp failure indicator
The trailer recognition control unit monitors the function of the bulbs 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 dropped below a fault message appears in the multifunction display of the instrument cluster although the function of the trailer lighting is OK.
Emergency light function
If the trailer recognition control unit fails or if there is a corresponding request placed via the interior CAN, the trailer's taillights are actuated.
Consumer shutoff
Following an appropriate request from the rear control unit, circuit 30 to the trailer socket is switched off.
| Trailer recognition control unit wiring diagram | PE31.19-P-2101-97NBA |