Component Location
General Description
As inputted rail pressure sensor signal, ECM of Commom rail diesel engine controls Fuel pressure regulator valve(intergrated with high press. pump) in order to maintain optimum rail pressure according to current engine rpm and load.
However when the problem that leads rail pressure to out of target value intended by ECM occurs due to mechanical or electronical reason, ECM shuts engine down and sets DTC by limiting fuel (stops injector operation) in order to prevent engine from being controlled abnormally. "rail pressure monitoring error" is the DTC which diagnose 1).supplying state of low pressure fuel and 2).mechanical operating conditions of high pressure pump and 3) indirectly based on RPS output voltage and RPS duty. thus, repair relavant to this DTC requires mechanics the total understand of fuel system.
In U-2 Engine, Rail Pressure Regulator Valve That located on the Commom Railis is deleted.
DTC Description
P1185 is set when 1)rail press. is higher than target rail press. by 200~350bar in condition that rail press. is controlled by Fuel pressure regulator valve or 2)rail press. exceeds maximum limiting value. 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 fuel press. sensor.
DTC Detecting Condition
Item | Detecting Condition | Possible Cause |
DTC Strategy | Voltage monitoring
| Fuel pressure regulator valve (open stuck)
Rail pressure sensor (Output fixed at high voltage line)
|
Enable Conditions | Engine running
|
Threshold Value | Rail pressure is above target rail pressure by more than 200~350bar at Fuel pressure regulator valve operating condition.- 5000ms
Rail pressure is above maximum limiting value(1750bar) at Fuel pressure regulator valve operating condition. - 240 ms
|
Diagnostic Time | Refer to threshold Value
|
Fail Safe | Fuel Cut | NO | |
EGR Off | NO |
Fuel Limit | YES |
Check Lamp | YES |