P2543: Low Pressure Fuel System Sensor Circuit Intermittent
What to do
Notice whether the fault relates to how much fuel is in the tank — a pump drawing air when the level is low produces genuine pressure drop-outs, and a fault that appears on a low tank and clears after filling up is that rather than a wiring problem. That is information only you can supply. Otherwise expect the connector to be inspected; be aware that on many vehicles this sensor sits in the tank assembly, so reaching it is a bigger job than the part suggests.
What this code means
The low-pressure fuel reading jumps or drops out rather than changing smoothly.
Fuel pressure in a supply line does move quickly, so the module allows for genuine variation — what it catches here is change no hydraulic system could produce. That points at the connection.
One non-electrical explanation deserves eliminating first, because it is a real fault and it has a pattern: a fuel pump drawing air. A tank run habitually low, a cracked pickup or a failing strainer lets the pump pick up air intermittently, and the pressure genuinely collapses and recovers as it does. The signature is a fault that appears with a low tank and disappears after filling up — which the driver is far better placed to notice than a workshop.
Where the pattern has nothing to do with fuel level, the connector is the usual answer, and on tank-mounted sensors it is a connector inside or on top of the tank, which is a larger job to reach than most.
Likely causes
Start here
- Corroded or loose connector · moderate
- Intermittent wiring fault · moderate
- Fuel pump drawing air · moderate
Less common
- Weak fuel pump · moderate
- Faulty low pressure fuel sensor · moderate
- Restricted fuel filter · easy
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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