A engine distributes accumulated fuel in common rail transferred from high pressure pump to each cylinder evenly. RPS (Rail Pressure Sensor) is installed at the end of common rail. If fuel pressure in the common rail pushes PIEZO of RPS through the fuel passage, this fuel pressure is converted as electrical signal by PIEZO theory and senses fuel pressure in the common rail. ECM decides optimum injection fuel amount corresponding to RPS signal what engine requires. In addition that RPS signal is used for RPV feed back signal to control optimum rail pressure. Pressure fluctuation in rail pressure occurs due to high fuel injection pressure and multi injection (max. 6 cylinder) during injection in common rail diesel engine. To reduce fluctuation of this rail pressure, the engine has throttle inserted with pressurized in the connection of high pressure pipe on common rail. For reference, allowable pressure at common rail is under approximately 2000bar.
In case of replacing RPS, perform the "COMPONENT CHANGE ROUTINE" procedure with scan tool. If the "COMPONENT CHANGE ROUTINE" procedure has not completed until automatic learning completed, it may cause vehicle performance and exhaust gas problem.
P0193 is set when RPS output voltage is above the maximum value (4750mV) for more than 0.14 sec. This code is due to 1) short to battery in signal circuit 2) open in signal circuit or 3) open in ground circuit.
Item
Detecting Condition
Possible Cause
DTC Strategy
Voltage monitoring
RPS circuit
RPS component
Enable Conditions
Engine running
Threshold Value
Output signal above the maximum value (above 4750mV).
- Short to battery in signal circuit .
- Open in signal circuit.
- Open in ground circuit.
Diagnostic Time
0.14 sec.
Fail Safe
Fuel cut
NO
Rail press. Sensor value fixed at 330bar.
EGR Off
Fuel Limit
YES
Check Lamp
ON
Fig.1) APS & Rail Pressure at acceleration.
Rail pressure increases at sudden acceleration.