Bosch · Alarm List A/W Split (8754) 2018 01 10
This warning indicates an open circuit (resistance over 364 kOhm) for the discharge gas temperature sensor TR6.
Click steps to track your progress.
With the sensor disconnected from the I/O-module, check the resistance of sensor TR6 and its signal cable.
Compare the measured resistance to the table value in the documentation.
Replace the sensor if it is faulty or the cable is damaged.