Codes P2509

Good morning,

I posted dome possibilities below for the 2509. No code goes away on its own without proper diagnostics and repairs. Clearing codes does nothing as the issue needs to be addressed.

SYMPTOM
P2509-POWERDOWN DATA LOST ERROR

WHEN MONITORED
Continuous - key on or key off.

SET CONDITION
Loss of voltage detected at the ECM for a calibrated amount of time.

POSSIBLE CAUSES
- Poor connections at the batteries
- Low battery voltage
- Open fused B+ to ECM
- Open ground circuit
- Battery + shorted to other circuits
- Return circuit shorted
- Battery + shorted to ground
- Intermittent condition

This code is based around low voltage. Check the batteries first and have them load tested. Make sure the cables are tight and clean. Check the voltage drop to the starter to be sure there is not any corrosion in the cable itself.

https://www.2carpros.com/articles/everything-goes-dead-when-engine-is-cranked

https://www.2carpros.com/articles/car-battery-load-test

also, check the charging system as well to be sure it is maintaining the batteries.

https://www.2carpros.com/articles/how-to-check-a-car-alternator

The 148 codes. I posted some possible failures for this as well. Did you check the lift pump pressure?

SYMPTOM
P0148-HIGH PRESSURE COMMON RAIL (HPCR) CHECKSUM

WHEN MONITORED
While the engine is running.

SET CONDITION
A deviation between the fuel pressure set point and the actual fuel pressure.

POSSIBLE CAUSES
- Others DTC'S present
- Fuel leaks
- Fuel control actuator
- Fuel pressure sensor
- Cascade overflow valve
- Check valve damaged or blocked
- Fuel return lines obstruction, damage, or debris.
- Lift pump flow
- Air in fuel system
- Leaking fuel injectors or high pressure connectors
- Pressure limiting valve
- High pressure fuel pump
- Intermittent condition

Roy