P2543
Low Pressure Fuel System Sensor Circuit Intermittent
Fuel & air metering
Generic OBD-II
Medium
What it means
P2543 means the signal from the low-pressure fuel system sensor is cutting out or reading erratically — an intermittent fault in the sensor or its wiring rather than a steady failure. Because that sensor reports supply-side fuel pressure, a dropout can cause occasional hesitation, hard starting, or a stall, so it's worth chasing down even though the car usually still drives.
Medium
Can I keep driving? Usually yes, but an intermittent low-pressure fuel-sensor signal can cause hesitation, hard starting, or stalling; get it looked at before it strands you.
Common symptoms
What you'll notice
- Check-engine light on
- Intermittent hesitation or stumble
- Occasional hard starting or stalling
- Erratic fuel-pressure reading on a scan tool
Common causes
Most likely first
- Intermittent open or short in the low-pressure fuel-sensor wiringLikely
- Loose or corroded sensor connectorCommon
- Faulty low-pressure (lift-pump) fuel-pressure sensorCommon
- Poor ground or chafed harnessLess often
- Rarely, an ECM faultLess often
How to diagnose & fix
Work through it in order
- Read freeze-frame data to catch the conditions when it drops out.
- Wiggle-test the sensor connector and harness while watching the live fuel-pressure value.
- Inspect for chafed wiring and clean/reseat the connector.
- Compare the sensor reading against a mechanical gauge.
- Replace the sensor if it drops out, then clear and re-test.
FAQ
Quick answers
Is it safe to drive with P2543?+
Often yes, but an intermittent fuel-pressure signal can cause hesitation or an occasional stall. Diagnose it before a long trip so it doesn't leave you stuck.
Can I just clear P2543?+
An intermittent fault will keep returning. The code stays away only once the wiring, connector, or sensor is repaired.
Related codes
Often seen with P2543
Read & clear P2543 yourself
Scan your car, confirm the code, and clear it once it's fixed — with OBD DashX on your phone.
✓ Verified name — SAE J2012 / ISO 15031-6Guidance reviewed by OBD DashX