Fuel Delivery Error
The P0148 code means the vehicle's onboard diagnostic system has detected: Fuel Delivery Error. This is a moderate severity code.
- Keep driving?
- Short distances only
- DIY difficulty
- hard
- Estimated cost
- $100 - $800 (fuel filter $30-$80; fuel pressure regulator $100-$250; fuel pump $300-$700)
Test O2 sensor voltage (should fluctuate 0.1-0.9V). Do not replace a $150 sensor without confirming it is actually bad first.
Shows real-time O2 sensor readings on your phone. See if the sensor is lazy, stuck, or actually working before spending money.
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Common Symptoms
- Check Engine Light on
- Rough idle and engine hesitation
- Reduced engine power
- Poor fuel economy
- Engine may stall or misfire under load
Probable Causes (Ranked by Likelihood)
- Faulty fuel injector(s) delivering incorrect fuel quantity Very High
- Fuel pressure regulator malfunction High
- Weak or failing fuel pump Moderate
- Clogged fuel filter restricting flow Moderate
- PCM fuel control strategy error Low
Frequently Asked Questions
Can I drive with code P0148?
You can drive short distances, but the engine may run rough, lack power, or stall. The fuel delivery error means the engine is not getting the correct amount of fuel, which can worsen if ignored.
Is P0148 common on diesel engines?
Yes. P0148 is frequently seen on diesel engines, particularly Cummins, Power Stroke, and Duramax platforms. On diesels, it often relates to fuel injection pump or injector calibration issues.
Can contaminated fuel cause P0148?
Yes. Water or debris in the fuel can cause incorrect fuel delivery by clogging injectors, damaging the fuel pump, or affecting the fuel pressure regulator. If you suspect bad fuel, drain the tank and replace the fuel filter.
What actually makes the computer set an oxygen sensor code?
The OBD II regulation requires four separate detections for an oxygen sensor (Title 13 CCR 1968.2, section (e)(7.2)): deterioration in voltage, response rate or amplitude that would push emissions past 1.5 times the FTP standards; loss of circuit continuity; out-of-range values; and the case where the sensor has degraded enough that the fuel system stops using it and falls back to open loop. A sensor can therefore set a code while still producing a signal that looks plausible on a scan tool. This is the threshold the monitor is designed around, not a description of your specific fault — the regulation says what the system must detect, not how to find it on your vehicle.
Mechanics Guide Step-by-step diagnosis
Step-by-Step Diagnostic Procedure
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Connect a fuel pressure gauge to the fuel rail. Compare pressure to specifications (typically 45-65 psi for gasoline engines). Low pressure indicates a fuel pump or filter issue.
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Use a scan tool to check fuel trim values. Long-term fuel trims beyond plus or minus 10% indicate a fuel delivery problem.
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Perform a fuel injector balance test or flow test to identify any injectors delivering too much or too little fuel.
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Check the fuel pressure regulator for proper operation. With the engine running, disconnect the vacuum line to the regulator -- pressure should increase. If not, the regulator may be faulty.
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Inspect the fuel filter and replace if it has not been changed in 30,000 miles or more. On some vehicles, the filter is part of the fuel pump assembly.
Sources 3
This page is built from documented references. Verify against your own service info before repair work.
- California Code of Regulations, Title 13 section 1968.2 (OBD II)malfunction criteria, section (e)
- SAE J2012Diagnostic Trouble Code Definitions (defines the generic OBD-II code ranges)
- Cross-checked against the SAE J2012:2002 DTC table (2026-08-27)archived scan of the SAE standard — readable copy, not SAE’s current edition
P0148 on Diesel, EV & Equipment
The same code ID appears across other engines and platforms. The diagnostic flow varies by manufacturer — these are the platform-specific breakdowns:
Commonly Affected Vehicles
- 2003-2014 Dodge Ram (5.9L, 6.7L Cummins diesel)
- 2005-2015 Ford F-250 (6.0L, 6.7L Power Stroke diesel)
- 2007-2016 Chevrolet Silverado 2500 (6.6L Duramax diesel)
- 2008-2017 Toyota Tundra (5.7L V8)
- 2006-2014 Nissan Titan (5.6L V8)
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