I recently removed the car battery and plugged it again. I then noticed that when I turn the A/C on the RPM goes up and down 1000~500 rpm and sometimes when I shift the gear from N to D or R the car turns off.
I did an OBD check and the results were Code P0148
The error code represents "High Pressure Common Rail Checksum Error"
This could be the FCA (fuel control actuator) or a fuel pressure sensor on your main high pressure fuel rail or possibly both. The FCA meters fuel into the high pressure fuel rail.
Symptoms are typically sputtering and power loss off idle or higher. The symptoms you are experiencing could be associated with either failing.
I don't think the car battery disconnection is related to the issues you are experiencing but a more knowledgeable resource may chime in with experience that can connect the two together.
Best of luck
