P0148

P0148-FUEL DELIVERY ERROR

For a complete wiring diagram, refer to the Wiring Information Electrical Diagrams. Electrical Diagrams

- When Monitored:
While the engine is running.

- Set Condition:
A deviation between the fuel pressure set point and the actual fuel pressure.





Always perform the Pre-Diagnostic Troubleshooting procedure before proceeding. Pre-Diagnostic Troubleshooting Procedure.

1. OTHERS DTCS PRESENT
1. With the scan tool, read DTCs.

Are any other DTCs present?

Yes

- Repair other DTCs first.
- Perform the POWERTRAIN VERIFICATION TEST - 6.7L. Powertrain Verification Test.

No

- Go To 2

2. FUEL LEAKS
1. Make sure that the fuel level is above 15% using the scan tool.
2. Visually inspect the low and high pressure side of the fuel system for fuel leaks or damaged components.

Do you have any fuel leaks or damaged components?

Yes

- Repair the fuel leak.
- Perform the POWERTRAIN VERIFICATION TEST - 6.7L. Powertrain Verification Test.

No

- Go To 3

3. SETPOINT VS FUEL PRESSURE
1. With the scan tool watch fuel pressure vs.setpoint with the engine at idle or cranking?
2. Is the pressure within 500 psi ± of set point?



If psi is within 500 psi,

- Document DTC and freeze frame data and attempt to duplicate complaint.
- Perform the POWERTRAIN VERIFICATION TEST - 6.7L. Powertrain Verification Test.

If the psi is higher than setpoint,

- Go To 9

If the psi is lower than setpoint,

- Go To 4

4. LIFT PUMP FLOW
1. Perform the IN TANK FUEL LIFT PUMP FLOW TEST. In-Tank Fuel Lift Pump Flow/Diagnostic Test Procedure

Did the Lift pump pass the flow test?

Yes

- Go To 5

No

- Replace the Lift Pump.
- Perform the POWERTRAIN VERIFICATION TEST - 6.7L. Powertrain Verification Test.

5. HIGH PRESSURE FUEL PUMP
1. Perform the no trouble code test HIGH PRESSURE FUEL PUMP PERFORMANCE TEST.

Did the fuel pump pass the high pressure fuel pump performance test?

Yes

- Go To 6

6. LEAKING FUEL INJECTORS OR HIGH PRESSURE CONNECTORS
1. Perform the INJECTOR RETURN FLOW TEST. Injector Return Flow Test

Are any Injectors leaking or high pressure connectors leaking?

Yes

- Replace or repair the leaking fuel injectors or high pressure connectors.
- Perform the POWERTRAIN VERIFICATION TEST - 6.7L. Powertrain Verification Test.

No

- Go To 7

7. HIGH PRESSURE PUMP
1. Perform the FUEL PUMP RETURN FLOW TEST.

NOTE: This test can be performed at the same time as the Injector Return Flow test that is listed in step 8 by measure the flow that is normally wasted.

Is the drain flow measured less than 1000 ml/minute at idle?

Yes

- Go To 8

No

- Replace Fuel Injection Pump.
- Perform the POWERTRAIN VERIFICATION TEST - 6.7L. Powertrain Verification Test.

8. PRESSURE LIMITING VALVE PRESSURE LIMITING VALVE
1. Perform the PRESSURE LIMITING VALVE TEST.

Did the Pressure Limiting Valve pass the test procedure?

Yes

- Go To 9

No

- Replace the Pressure Limiting Valve.
- Perform the POWERTRAIN VERIFICATION TEST - 6.7L. Powertrain Verification Test.

9. FUEL CONTROL ACTUATOR
1. Check for a mechanically stuck Fuel Control Actuator (FCA). Using the scan tool, actuate the Fuel Control Actuator.

NOTE: The Fuel Control Actuator will only click when cycled off.

Do you hear a click from the actuator when you cycle the actuator off with the scan tool?

Yes

- Go To 10

No

- Replace the Fuel Control Actuator.
- Perform the POWERTRAIN VERIFICATION TEST - 6.7L. Powertrain Verification Test.

10. CHECK VALVE DAMAGED OR BLOCKED
1. Check the fuel drain line check valve in the rear of the cylinder head for signs of damage, blockage, or debris.

Is the check valve damaged or blocked?

Yes

- Repair the cause of the damaged or blocked check valve or replace the valve.
- Perform the POWERTRAIN VERIFICATION TEST - 6.7L. Powertrain Verification Test.

No

- Go To 11

11. FUEL PRESSURE SENSOR
1. Using the scan tool, monitor the fuel pressure reading from the fuel rail pressure sensor at idle and at 2000 RPM.

Is the fuel rail pressure reading higher at 2000 RPM than at idle?

Yes

- Perform the INTERMITTENT CONDITION diagnostic procedure. Intermittent Condition Test.

No

- Replace the Fuel Pressure Sensor.
- Perform the POWERTRAIN VERIFICATION TEST - 6.7L. Powertrain Verification Test.