What P0148 means
P means powertrain (engine and transmission). The 0 marks a generic code defined by SAE, so the same number means the same thing across makes. The third character, 1, places it in the fuel and air metering subsystem; the last two digits identify the specific fault.
On diesel engines the engine computer controls both how much fuel is injected and exactly when. These codes mean the delivered fuel quantity or injection timing did not match what was commanded, judged from sensors such as rail pressure, crank speed and timing feedback.
What “Fuel Delivery Error” means here
The quantity of fuel delivered did not match what the module commanded. Possible reasons include restricted fuel supply (filter, water, air ingress), a weak high-pressure pump, a pressure regulator problem, or leaking injectors.
What you may notice
Symptoms depend on the vehicle and on how the module responds to the fault. Any of these can accompany P0148:
- Hard starting
- Loss of power or limp-home mode
- Excess smoke
- Knocking or rough running
Where to start diagnosing P0148
- Check fuel quality and the fuel filter, and drain any water separator.
- Look for air in the fuel supply on the low-pressure side.
- Read rail or pump pressure in live data and compare commanded with actual.
- Follow the manufacturer's procedure for injector or pump timing checks.
Clear the code only after recording freeze frame data: it shows the engine speed, load and temperature at the moment the fault set, which is often the best clue to reproducing it.
Live data to watch
These standard OBD2 values relate to P0148. Support varies by vehicle; a value your car does not report will simply be missing.
| Value | What to look for |
|---|---|
| Fuel rail pressure (PID 0x23) | Actual should track commanded closely. |
| Fuel injection timing (PID 0x5D) | Where supported, compare with expected values. |
| Engine RPM (PID 0x0C) | Look for unstable idle speed. |
Related codes
Codes from the same diesel fuel injection control family. If several are stored together, the shared part — wiring, a common reference voltage, or the component itself — is the place to start.
Further reading
Frequently Asked Questions
What does P0148 mean?
P0148 is the generic SAE J2012 code for "Fuel Delivery Error". In plain terms, it means the engine computer's diesel fuel injection control monitor has reported "Fuel Delivery Error".
Can I keep driving with P0148?
A diesel fuel delivery or timing fault can cause sudden power loss. Get it checked before long trips.
What should I check first for P0148?
Check fuel quality and the fuel filter, and drain any water separator.
Definition source: SAE J2012 / ISO 15031-6 generic DTC definitions. This is the generic meaning that applies across makes; a manufacturer can define a code more narrowly or add its own sub-codes, so confirm against the service information for your vehicle before replacing parts. Written by the OBDAssistant engineering team — see our editorial policy.