P2542: Low Pressure Fuel System Sensor Circuit High
What to do
Expect rough running or poor starting, or possibly nothing at all. If work has been done on the fuel tank or pump recently, ask for the sensor connector to be checked first — it is easily left unconnected during that job. Mention any smell of fuel, which would suggest genuine over-pressure stressing the supply hoses rather than a wiring fault.
What this code means
The low-pressure fuel sensor circuit reads above its valid range — an open circuit, a disconnected sensor, or a genuinely excessive feed pressure.
Excess low-side pressure is worth taking seriously rather than assuming a wiring fault. On a regulated system it means the pump is not being throttled back as commanded, and the surplus has to go somewhere: it loads the high-pressure pump's inlet beyond design, stresses the supply hoses, and on a returnless system there is no relief path other than the components themselves.
An open circuit remains the more common finding, and on vehicles where the sensor sits in the tank assembly, work on the fuel pump or the tank is a strong pointer to a connector left unseated.
Likely causes
Start here
- Open circuit in sensor wiring · moderate
- Disconnected sensor connector · easy
- Faulty low pressure fuel sensor · moderate
Less common
- Faulty fuel pump control module · specialist
- Blocked fuel return line · moderate
- Wiring shorted to voltage · moderate
Symptoms
Components involved
Information, not instruction
CarGeek is a reference, not a service manual. Its pages are written from public sources and from what other people have found, never from a manufacturer's own service information, so they can be wrong or incomplete for your particular vehicle. Some of what they describe carries real risk: high voltage, fuel under pressure, stored energy, hot and moving parts.
Have anything you intend to act on checked by a trained person against the manufacturer's own procedure for your vehicle. Nothing here replaces that procedure.
Community experience
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