P0233 Fuel Pump Secondary Circuit Intermittent

P0233 indicates an intermittent fault in the fuel pump secondary circuit. The pump output circuit drops out or becomes abnormal only at times.

Code details

Generic OBD-II · P0

System: Fuel / Air
Code type: Generic (SAE / ISO controlled)
Standard: SAE J2012 / ISO 15031-6

Diagnostic boundary

A diagnostic trouble code reports that a monitored test failed. It does not prove one specific part is bad, and manufacturer logic can add vehicle-specific conditions.

Do not clear an intermittent fuel pump circuit code without a loaded voltage and connector check.

Symptoms of P0233

Check-engine light on, sometimes with rough or uneven running.
Hesitation, surging, or a noticeable change in fuel economy.
Occasionally hard starting or a smell of unburnt fuel.

Common causes of P0233

A failing or contaminated sensor (MAF, MAP, oxygen or air-fuel sensor).
Intake or vacuum leaks, or an exhaust leak near an upstream sensor.
Wiring, connector, or fuel-delivery problems that skew the reading.

Useful checks before replacing parts

Monitor pump voltage, fuel pressure, and command state while repeating the freeze-frame load and vibration conditions.
Inspect relay sockets, pump connector terminals, tank harness routing, grounds, and corrosion-prone connectors.
Check for intermittent stalling, hard start, or pressure drop events that match the circuit fault.

Related OBD-II codes

These nearby fuel / air entries can help compare wording and pin down the fault area.