P1185 is set when 1) rail pressure is higher than target rail pressure by 200bar in condition that rail pressure is controlled by fuel metering unit (P-PRV) or 2) rail pressure exceeds maximum limiting value 1990 bar. This code is due to 1) more than intended fuel supply to common rail or 2) poor return of fuel supplied to common rail or 3) short to high voltage line in RPS. (Leakage on high pressure pipe / Injector open stuck / Over wear on high pressure / Excessive fuel return amount caused by injector over wear / Leakage on low pressure line / Clogged on fuel filter / Low pressure motor performance error)