RPS(Rail Pressure Sensor), consists of piezzo electric element, measures rail pressure inside of common rail.
ECM determines optimum fuel injection quantity at specific engine condition based on RPS signal. RPS signal is also used as rail pressure regualtor feed back signal in order to achieve optimum rail pressure at certain engine condition.
1. Connector
2. Measurement circuit
3. Sensor element(diaphragm)
4. Rail pressure
5. Fuel rail
P0088 is set when RPS output value is above the maximum value for 1.5 sec.. This code is due to the open in power circuit or the short to ground in signal circuit.
Item
Detecting Condition
Possible Cause
DTC Strategy
Pressure monitoring
RPS circuit
RPS component
Enable Conditions
Engine running
Threshold Value
Output value of Rail pressure is higher than maximum pressure(1777bar).
Diagnostic Time
1.5 second
Fail Safe
Fuel cut
NO
EGR Off
Fuel Limit
YES
Check Lamp
Fig 1) This waveform shows the rise of RPS output voltage at rapid acceleration.