DPF sensors are not known for unreliability. They are usually telling the truth. You may be trying to shoot the messenger here.
If the sensor is telling you there is a problem, have a look at the problem it is suggesting.
The sensor will be on the DPF I guess. To find the DPF, follow the exhaust system, from the cylinder head. Check all offshoots, as I think the DPF takes some but not all of the exhaust. You are looking for a canister with exhaust input and output, and some electrical connections. It needs to be somewhere where it can lose a lot of heat when it is regenerating, so is likely to be somewhere visible.
You don't state what the actual problem is, only that you seem to dislike the sensor reporting something. Quite likely it needs a forced regen.