What is the code for fuel pump circuit open?
There is no single universal diagnostic code that specifically reads “fuel pump circuit open.” In practice, the generic OBD-II codes most often associated with fuel pump circuit problems are P0620 and P0622, with some manufacturers using P0690 to denote a fault in the fuel pump driver/module. The exact code shown depends on the vehicle’s make, model, and the control module’s fault tracking.
In more detail, an “open” condition in the fuel pump circuit means the electrical path to the pump is interrupted or not being completed by the control system. This can stem from a blown fuse, a faulty relay, damaged wiring or connectors, a failed fuel pump, or a malfunctioning pump driver/module. Because manufacturers implement and name these faults differently, the specific code you see should be interpreted using your vehicle’s service documentation and a compatible diagnostic tool.
Understanding fuel pump circuit DTCs
These codes indicate issues in the circuit that powers or controls the fuel pump. They are used by technicians to locate faults in the pump, its relay, driver, or the wiring between them. Variations exist by OEM, so two cars from different brands may report different codes for similar symptoms.
Common generic codes you might encounter related to the fuel pump circuit
- P0620 – Fuel Pump Control Circuit
- P0622 – Fuel Pump Control Circuit Low
- P0690 – Fuel Pump Driver Module/Control Circuit
These codes do not automatically tell you exactly which component is failed; they indicate the fault pathway. Always verify with the specific vehicle’s diagnostic documentation and live data to pinpoint the source.
Diagnostic steps for an open fuel pump circuit
Before starting hands-on diagnostics, you should understand the general approach and safety concerns. The following steps help identify whether the problem is electrical, mechanical, or related to the pump itself.
- Check fuses and relays dedicated to the fuel pump circuit and verify they are functioning and have proper voltage.
- Inspect the fuel pump fuse/relay wiring harness for corrosion, loose connections, or damaged insulation.
- Test the inertia switch (if equipped) to ensure the pump is allowed to run; reset if tripped.
- Inspect wiring and connectors at the fuel pump, including power and ground paths; look for damaged wires, pin corrosion, or loose grounds.
- Measure the voltage supply at the pump connector with the ignition on and during cranking to confirm an appropriate supply.
- Check the ground circuit for solid continuity to the chassis/PCM.
- If possible, measure the pump’s current draw with a multimeter or an ammeter to ensure it is within manufacturer specifications.
- Use a scan tool to monitor live data: pump relay status, supply voltage to the pump, and pump duty cycle while the engine is cranking or running.
- Consider testing with a known-good pump or FPDM (fuel pump driver module) if your vehicle uses an external driver, to isolate whether the fault lies in the pump, the driver, or the wiring.
After completing these checks, compare the findings with the vehicle’s service information and repair guidelines to determine the exact replacement or repair path. If you’re not comfortable performing electrical diagnostics, seek professional help, as fuel-system work involves fire risk and may require specialized tools.
OEM variations and next steps
Since manufacturers may label and interpret fuel pump circuit faults differently, always cross-check the exact DTC definitions with your vehicle’s service manual or OEM software. Some models may present related codes that reflect driver-module faults or sensor feedback in the fuel system. If you have access to manufacturer-specific diagnostic databases or technical bulletins, use them to confirm the meaning of the code and any recommended troubleshooting steps for your car.
When to replace or repair
Repairs typically follow a fault tree aligned with the diagnostic results. Common outcomes include replacing a blown fuse or relay, repairing damaged wiring or connectors, replacing the fuel pump, or replacing the fuel pump driver/module if the driver is found to be the source of the fault. Always verify fuel pressure and pump operation after repairs to confirm the issue is resolved.
Summary
In short, there isn’t a single universal “fuel pump circuit open” code. The most common generic codes tied to fuel pump circuit problems are P0620, P0622, and P0690, but OEMs may use different codes or descriptions. Accurate diagnosis relies on reading the exact code with your vehicle’s scan tool, confirming live data, and methodically checking power, ground, wiring, relays, and the pump itself. When in doubt, consult the vehicle’s service documentation or a qualified technician to ensure a safe and correct repair.
