Low Pressure Fuel System Sensor Circuit High
The P2542 code means the vehicle's onboard diagnostic system has detected: Low Pressure Fuel System Sensor Circuit High. This is a critical severity code.
- Keep driving?
- No — stop driving
- DIY difficulty
- hard
- Estimated cost
- $150 - $600 (parts and labor)
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What Are the Symptoms of P2542?
- Engine runs lean and misfires
- Loss of power
- Check engine light on
- Possible fuel pump running at reduced speed
What Causes P2542? (Most Likely First)
- Fuel pressure sensor shorted to reference voltage Very High
- Signal wire shorted to power High
- Excessively high fuel supply pressure Moderate
- Stuck fuel pressure regulator Low
Can I Still Drive with P2542?
No — stop driving. P2542 is rated critical severity. Continuing to drive in this state risks further damage — get it looked at before your next trip.
Frequently Asked Questions
Why does a high sensor reading cause lean running?
When the ECM sees higher-than-actual pressure, it reduces fuel pump speed and shortens injector pulse width, thinking plenty of fuel is available when it may not be.
Can high fuel pressure damage injectors?
Yes. Excessive fuel pressure can overwhelm injector seals and cause leaking, leading to rich conditions, fouled spark plugs, and potential engine damage.
What is normal low-pressure fuel system pressure?
Typical low-pressure fuel supply runs 40-80 PSI depending on the system. P2542 sets when the sensor reports values above the expected maximum.
Mechanics Guide Step-by-step diagnosis
How Do You Diagnose P2542?
-
Check sensor signal voltage for constant near-5V reading
-
Test signal wire for short to battery or reference voltage
-
Measure actual fuel supply pressure with gauge
-
Inspect fuel pressure regulator for stuck-open condition
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
Which Vehicles Commonly Get P2542?
- 2010-2020 Ford Mustang EcoBoost
- 2012-2020 Hyundai Sonata
- 2011-2019 Kia Optima
- 2010-2018 Chevrolet Malibu
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