Hi
We have a VW Sharan S TDi (2011 diesel)
Be very grateful for any advice in tracing a possible fault that our VW garage can’t identify.

The cat converter light warning is coming on intermittently

We had the following readings from the diagnostics

“1 Fault Found:

9632 - Reductant Level Sensor
P203B 00 [00101000] - Implausible Signal
Intermittent - Confirmed - Tested Since Memory Clear
Freeze Frame:
Fault Priority: 2
Fault Frequency: 15”

The garage is unsure what the issue is but suggests either reduction tank or sensor repair kit.

Car has always been very reliable until last 6 months when we have spent a lot of money on ( unrelated) faults. Not sure whether to throw more money at the car at this stage.
Be very grateful for any guidance as to what the prospects are for this fault..,,
Many thanks.