F.342
The air-mass flow is not within the permitted limits.
Vaillant ecoTEC Plus System
Possible cause
Fan speed does not correspond to the target value
Measure
Use D.033 and D.034 to check whether the fan speed deviates by more than 20–30 rpm.
Possible cause
Plug on PCB loose/not plugged in
Measure
Check the plug and the plug connection.
Possible cause
Interruption in the wiring harness
Measure
Check the wiring harness including all plug connections and, if required, replace it.
Possible cause
Air-mass flow sensor plug loose/not plugged in
Measure
Check the plug and the plug connection for the air-mass flow sensor.
Possible cause
You exit the measuring range permanently. Air-mass flow sensor defective
Measure
Replace the entire air intake pipe.
Possible cause
Flue gas pipe blocked
Measure
Check the entire flue gas pipe.
This code also applies to: