The only sensor I know of is the pressure test pump up under the spare wheel.
The loose cap warning is caused by the tank not holding pressure during the test or the pressure test pump not working. If it only happens when wet I would check the connections on the test pump.
Also I think the wires to that pump run up under the passenger wheel well underneath the splash guard. There are a couple plugs and some other wiring tht might also get wet and short out.
The loose cap warning is caused by the tank not holding pressure during the test or the pressure test pump not working. If it only happens when wet I would check the connections on the test pump.
Also I think the wires to that pump run up under the passenger wheel well underneath the splash guard. There are a couple plugs and some other wiring tht might also get wet and short out.