Audi TT Roadster, Service Training

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Electrical convertible top control system
Convertible top operation control unit J256
Convertible top operation control unit J256
Automatic or fully automatic convertible top
operation is only possible using the convertible
top operation control unit J256.
The convertible top operation control unit J256
gathers information from the sensors, evaluates
this and activates the actuators.
The convertible top operation control unit J256 is
also responsible for system diagnostics.
If a faulty actuator or a sensor is identified or if the
signals from the sensors are not received in time,
the control unit stops the convertible top operating
cycle. A fault is stored in the fault memory.
In addition, the control unit monitors the operating
time of the convertible top. In order to avoid
overloading the hydraulic pump, the convertible top
operation control unit J256 deactivates the
convertible top after approx. three minutes,
provided that the convertible top is closed. The convertible top can be operated again until a
time-out of approx. ten minutes has expired. If the
convertible top does not meet the "closed"
condition after approx. four minutes of continuous
operation, the control unit stops the convertible top
operating cycle immediately. The convertible top
cannot be operated again until a 20 minute time-out
has expired. The actuation time of the convertible
top lock motor is also used for monitoring the
operating time of the convertible top.
The convertible top operation control unit J256
is integrated in the convenience CAN bus and
exchanges data with other vehicle systems
across this bus.
The control unit is housed in the luggage
compartment under the cargo floor.