What Does P0148 Mean?
The PCM has detected that the fuel delivery system is not providing the correct amount of fuel as commanded. This code is most commonly associated with diesel fuel injection systems where the actual fuel delivery deviates significantly from the desired fuel delivery. The driver may notice rough running, loss of power, excessive smoke, or poor fuel economy. This can also occur on gasoline direct injection systems.
Common Causes
30%
Faulty or worn high-pressure fuel pump not maintaining correct fuel rail pressure
25%
Leaking or clogged fuel injectors delivering incorrect fuel quantities
20%
Fuel pressure regulator malfunction or fuel rail pressure sensor error
15%
Restricted fuel filter or fuel supply line reducing fuel volume
10%
Air intrusion into the fuel supply system (diesel) or fuel system contamination
Diagnostic Steps
1
Monitor fuel rail pressure on live data at idle and under load — compare actual pressure to desired pressure; a deviation greater than 10% indicates a delivery problem.
2
Check fuel injector balance rates or correction values on live data — values outside +/-4 mg/stroke indicate individual injector issues.
3
Perform a fuel pressure leak-down test: key off after running, fuel pressure should hold within 10% for at least 10 minutes; rapid drop indicates a leaking injector or check valve.
4
Inspect the fuel filter — replace if past service interval. On diesel systems, check the water separator and bleed any air from the fuel system.
5
Verify the high-pressure fuel pump metering valve operation by commanding different fuel rail pressures with a scan tool and confirming the actual pressure follows.
Estimated Repair Cost
$200 - $1,500
Parts + labor, varies by vehicle and location
The PCM has detected that the fuel delivery system is not providing the correct amount of fuel as commanded. This code is most commonly associated with diesel fuel injection systems where the actual fuel delivery deviates significantly from the desired fuel delivery. The driver may notice rough runn...
The most common cause of P0148 (Fuel Delivery Error) is: Faulty or worn high-pressure fuel pump not maintaining correct fuel rail pressure
Typical repair costs for P0148 range from $200 to $1,500, depending on the vehicle, location, and whether you do it yourself or go to a shop.
Drive with caution. Incorrect fuel delivery can cause loss of power, stalling, or rough running that may be hazardous in traffic. On diesel vehicles, running lean can damage injectors and turbochargers. Have the vehicle diagnosed promptly.
Start by connecting an OBD2 scanner to read the code and any freeze frame data. Then follow the diagnostic steps specific to P0148 to identify the root cause.
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Quick Info
Category
Powertrain
System
Fuel System
Difficulty
Type
Generic (SAE)
Recommended Tools
OBD2 Scanner
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