Re: 250hpdi tach gauge
the oil tank has a switch that will alert the operator that the remote tank is low by illuminating a single middle bar.
3 bars flashing will indicate the ECU sees,via the remote tank switch, that there is enough oil for automatic transfer yet the engine oil tank is telling the ECU the engine tank is low.
2 bars flashing is typically wrong dip switch setting or sometimes the switches need to be reset.
sometimes they lose contact and must me cycled, dunno why but its the way life is.