Fault code P0231 – a step-by-step guide to diagnosing and fixing it

Error code P0231 is displayed and the check engine light is on - what does this mean?

The OBD/EOBD system has detected a fault in the fuel pump system, more precisely a low current or an interruption in the fuel pump secondary circuit. This DTC P0231 affects the electrical supply to the fuel pump and can occur with different manufacturers, although the diagnosis is basically similar.

What causes can this fault code have?

• Defective fuel pump
• Damaged fuel pump relay
• Blown fuel pump fuse
• Corroded or loose plug connections
• Damaged wiring to the fuel pump system
• Defective fuel pump driver in the control unit
• Poor ground connection of the fuel pump
• Defective fuel tank pressure sensor

What symptoms occur in parallel with fault code P0231?

• Starting problems: The vehicle is difficult or impossible to start
• Loss of power: Significant drop in engine power while driving
• Jerking: Engine runs rough or stutters, especially under load
• Stalling: Engine stalls while driving or stops idling
• Smell of fuel: Smell of fuel inside or around the vehicle
• Poor acceleration: Delayed response when accelerating

How to fix the problem of error code P0231?

• The repair requires a systematic diagnosis of the fuel pump system, starting with the electrical check.
• Checking and replacing the fuel pump fuse in the fuse box, followed by a functional test of the system
• Replacing the fuel pump relay after locating it in the relay box and comparing it with an identical relay
• Clean all plug connections of the fuel pump with contact spray and check for tight fit
• Voltage measurement on the fuel pump and repair or replace the wiring if the values are low
• Replacement of the complete fuel pump including delivery unit if the pump is defective after pressure test
• Checking the ground connections and cleaning the ground points on the fuel tank