P1643: Fuel Pump Monitor Circuit Low Input
MediumPowertrainFuel System
What does P1643 mean?
P1643 is a diagnostic trouble code indicating "Fuel Pump Monitor Circuit Low Input". The ECU is detecting a voltage reading that is below the expected range in the fuel system circuit. This typically points to a wiring short, a faulty sensor, or a grounding issue.
Common causes
- Damaged or corroded wiring harness
- Loose or disconnected electrical connector
- Failed fuel system sensor or actuator
- Blown fuse in the related circuit
- Poor ground connection
What should you do?
Schedule a diagnostic appointment at your earliest convenience. The vehicle is generally safe to drive short distances, but the underlying issue should be addressed to prevent it from worsening.
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Code P1643 can mean different things depending on your vehicle. TorqueBot gives you a diagnosis specific to your make, model, and year.