F.013
The cylinder temperature sensor has short-circuited.
Vaillant ecoTEC Plus Combi
Possible cause
Fault in the electrical connection for the cylinder temperature sensor
Measure
Check and, if required, replace the wiring harness between the PCB and sensor, including all plug connections.
Possible cause
Cylinder temperature sensor defective
Measure
Check and, if required, replace the cylinder temperature sensor.