If you are getting a charge error on an E or F, start by checking the LS pressure for the fan circuit then move to the brake pressures, if you are getting proper pressure, then check the amount the pressure drops when the pedal is depressed, this will verify the accumulator is OK.
If your LS pressure is in need of adjustment , do it in 1/2 turn increments, also remember to discharge the brake system prior to connecting your guages etc..