Loose, corroded, or damaged electrical connector at the low-pressure fuel sensor; Chafed or broken wire in the sensor circuit (signal, ground, or reference voltage); Failing low-pressure fuel sensor itself, causing intermittent signal dropouts; Poor ground connection for the sensor or PCM, leading to voltage fluctuations; Fuel contamination or debris interfering with sensor operation; PCM software glitch or internal fault (rare, but possible)

DTC codes / P25xx · Vehicle speed, idle control and auxiliary inputs / P2543

P2543Low Pressure Fuel System Sensor Circuit Intermittent

Q: What does code P2543 mean?

Low Pressure Fuel System Sensor Circuit Intermittent. P2543 indicates that the powertrain control module (PCM) has detected an intermittent fault in the electrical circuit of the low-pressure fuel system sensor, which monitors fuel pressure before the high-pressure pump on direct-injection engines. The PCM sets this code when the sensor signal momentarily drops out or becomes erratic, often due to a loose connection or chafed wire, rather than a hard failure.

P2543 indicates that the powertrain control module (PCM) has detected an intermittent fault in the electrical circuit of the low-pressure fuel system sensor, which monitors fuel pressure before the high-pressure pump on direct-injection engines. The PCM sets this code when the sensor signal momentarily drops out or becomes erratic, often due to a loose connection or chafed wire, rather than a hard failure.

SystemPowertrain

Code typeGeneric (all makes)

SeverityMedium

Fix difficultyIntermediate

AreaVehicle speed, idle control and auxiliary inputs

Symptoms you may notice

Illumination of the check engine light, often with no other noticeable symptoms
Intermittent hesitation or stumble during acceleration, especially when the engine is cold
Occasional rough idle or stalling when coming to a stop
Reduced fuel economy or a rich/lean condition that may trigger other codes
A pending code that appears and disappears over several drive cycles

Common causes, most likely first

Loose, corroded, or damaged electrical connector at the low-pressure fuel sensor
Chafed or broken wire in the sensor circuit (signal, ground, or reference voltage)
Failing low-pressure fuel sensor itself, causing intermittent signal dropouts
Poor ground connection for the sensor or PCM, leading to voltage fluctuations
Fuel contamination or debris interfering with sensor operation
PCM software glitch or internal fault (rare, but possible)

How to diagnose and fix it

Inspect the sensor connector and wiring for looseness, corrosion, or damage; clean and secure as needed
Perform a wiggle test on the harness while monitoring live sensor data to identify intermittent opens
Check the sensor's reference voltage and ground circuits with a multimeter to confirm integrity
Replace the low-pressure fuel sensor if wiring is intact but the signal remains erratic
Verify fuel pressure with a mechanical gauge to rule out actual low-pressure fuel delivery issues
Reprogram or replace the PCM only after all other causes have been eliminated

Intermittent faults often hide in the harness

A common oversight is replacing the sensor without first checking the connector pins for slight looseness that only acts up under vibration.
The code can be set by a momentary voltage drop caused by a poor ground shared with other sensors, so inspect ground points as well.
In some vehicles, the low-pressure fuel sensor is part of a combined module, and a fault in the high-pressure system can cause misleading intermittent signals.
A failing fuel pump control module can produce intermittent sensor readings without setting a pump-specific code, so check for related codes.
After repairs, clear the code and perform a drive cycle that includes varying engine loads to confirm the intermittent fault is resolved.

Can I keep driving with P2543?

The vehicle is generally safe to drive with this code because it indicates an intermittent electrical issue rather than a hard failure, but avoid aggressive acceleration or towing until it is diagnosed. If the engine begins to stumble or stall frequently, stop driving and seek professional repair to prevent potential fuel system damage.

Tools that help

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Guidance is general and written for all OBD-II vehicles. Exact tests and values vary by model, so confirm the fault before replacing parts.