It means the filter needs replacement
Gauge?
Each time the heart contracts a sound is heard, a gauge on the sphygmomanometer measures the pressure that blood exerts during ventricle contraction.
bad sending unit in tank, or short in wireing.
Water has a high pressure all the time.
It will be a oil pressure sensor
Sand filters usually have a pressure gauge in front of them indicating the back pressure before the filter.When the filter needs to be cleaned this pressure gets high. usually it has a red section on the gauge. When it hits the red it is time to think about back washing. If the gauge does not work as so often happens with these things. you can usually judge it from the lack of suction coming from the filter. After backwash you will note the pressure will be down and the suction will be up.
bad ground or float stuck 2 possibilities i can think of
To give the operator of the vehicle a real time and accurate check on the oil pressure of the engine.
if its an older worn out bottom end (bearings and oil pump) its probably time to do an overhaul, start it and see if the gauge reads oil pressure, a Chevy smallblock can run with just 4 lbs of oil pressure
The fuel gauge on a 1985 Chevy Silverado will read full all the time if the sending unit is defective or the wire has come loose. When the tank is full, the sending unit normally shuts off which cause the gauge to read full.
25 pounds per square inch is about 1.7atm
Try and disconnect the wire on the pressure switch located on the top rear side of engine near were transmission hooks up and see does pressure go down if so it's a bad switcg