Fuel System Leak Detected - Large Leak
The P0093 code means the vehicle's onboard diagnostic system has detected: Fuel System Leak Detected - Large Leak. This is a critical severity code.
- Keep driving?
- No — stop driving
- DIY difficulty
- hard
- Estimated cost
- $200 - $800 (parts and labor)
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Common Symptoms
- Check Engine Light on
- A scan tool shows Fuel System Leak Detected - Large Leak as the stored fault
- Drivability may be normal - many faults in this circuit show no symptom the driver notices
- The system may fall back to a default strategy until the fault is cleared
Probable Causes (Ranked by Likelihood)
- Wiring or connector fault at the fuel system - chafed harness, corroded pins, or a loose ground High
- Failed fuel system Medium
- A supply or reference voltage problem shared with other circuits, which usually sets companion codes too Medium
- Control module fault - rare, and only after the wiring and the component have both been ruled out Low
Frequently Asked Questions
What does P0093 mean?
Fuel System Leak Detected - Large Leak. That definition comes from SAE J2012, the standard that assigns generic OBD-II trouble code meanings.
Is P0093 the same on every vehicle?
The definition is standardized, but the exact test that sets it, the specified voltages and the physical location of the component vary by make and model. Check your vehicle's service information for those.
Mechanics Guide Step-by-step diagnosis
Step-by-Step Diagnostic Procedure
-
Read ALL stored codes first. Faults in this area often set several codes at once, and the cheapest cause is usually shared wiring rather than the part.
-
Inspect the connector and harness at the fuel system for corrosion, backed-out pins, and chafing before testing anything electrically.
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Back-probe the circuit with the connector attached and compare the reading against the manufacturer's specification for your vehicle - generic values do not apply across makes.
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Check power, ground and reference voltage feeding the circuit before condemning the component.
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Replace the component only after the wiring tests good. Confirm the repair by clearing the code and verifying it does not return under the conditions that set it.
Sources 2
This page is built from documented references. Verify against your own service info before repair work.
- 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
P0093 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
- 2010-2020 Ford F-150 (3.5L EcoBoost)
- 2012-2019 Chevrolet Silverado (5.3L GDI)
- 2008-2018 BMW X3 (2.0T)
- 2011-2020 Volkswagen GTI (2.0T)
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