Press the OFF button to turn off the air climate control system. However, you can still operate the air intake buttons as long as the ignition switch is in the ON position.
Kia Cee'd JD Service Manual: Rail Pressure Sensor (RPS) Repair procedures
Inspection
1.
Connect the GDS on the Data Link Connector (DLC).
2.
Measure the output voltage of the RPS at idle and various engine speed.
Condition
Output Voltage (V)
...
Kia Cee'd JD Service Manual: Specifications
Specifications
Items
Specifications
Rated voltage
5V
Load
Max. 1mA (When head lamp lighting)
Illuminations (LUX)
50
1.42 ± 0.31V
150 ...