Code Definition

P0231 — Fuel Pump Secondary Circuit Low

System: Powertrain  |  Type: Generic (OBD-II Standard)  |  Make: Generic

About P0231

P0231 is a generic (obd-ii standard) powertrain diagnostic trouble code. It belongs to the P-prefix family of codes, which covers engine, transmission, emissions, or fuel-system faults.

When P0231 is stored, the module has detected a signal or supply voltage lower than the expected operating range.

Scanning & clearing: A generic OBD-II scan tool will usually read and clear powertrain (P) codes. For live data, freeze-frame capture, and bi-directional tests you may need a more capable scan tool that supports the vehicle's ECM protocol.

Because P0231 is a generic OBD-II code, its base definition is shared across manufacturers. The specific diagnostic steps, reference values, and repair procedures can vary by vehicle, and the TaT Diagnostic Assistant includes verified procedures submitted by working technicians.

Code Information

The P0231 fault code is set when the Engine Control Module (ECM) detects a low voltage condition in the secondary circuit of the fuel pump. The secondary circuit typically refers to the wiring and connections from the fuel pump relay to the fuel pump itself. This code suggests that there is an issue with the electrical supply to the fuel pump, which can lead to inadequate fuel delivery to the engine. A low voltage condition in this circuit can be caused by various factors, including a faulty fuel pump relay, issues with the wiring or connectors, a blown fuse, or a malfunctioning fuel pump. Thi...

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