What is the P0231 fault number? What is the Fuel Pump Secondary Circuit Low Voltage fault description? How can you fix the fault code P0231? What are the causes and symptoms for the P0231 fault code
What is the P0231 fault code? What does it all mean?
A relay controlling the engine control module (ECM/PCM) activates the fuel pump. The fuel pump relay generates electricity that turns the fuel pump on or off.
For the fuel system’s proper operation, all components must be in perfect harmony. Low fuel pressure can lead to many problems. For example, fuel injectors cannot deliver fuel properly. Many electrical problems can lead to insufficient fuel pressure, including low voltage at the fuel pump. The ECM monitors the secondary circuit voltage signal of the fuel pump relay continuously. The P0231 fault code will be triggered if the voltage signal falls below a threshold.
A few vehicles have a feedback circuit within the fuel pump circuit. The problem most likely lies in the feedback circuit if fault code P0231 has been set.
What is the P0231 Fault Code?
Here are some reasons why P0231 should be set.
- – Defective fuel pump relay
- – Problems with the fuel pump supply circuit wiring
- – Connectors that are loose or damaged
- – Feedback circuit: Open or short circuit
- – Blown fuel pump fuse
- – Defective fuse box
- – Faulty or damaged fuel pump
What are the symptoms for P0231 Malfunction Codes?
You may experience the following symptoms if your vehicle has the code P0231:
- – Illumination for the check engine light
- – Engine won’t start, or stops running
- Engine misfire
- – Low fuel pressure / insufficient fuel supply
Your vehicle may not be showing any symptoms but is still running. You might experience a lack of acceleration, hesitancy or sudden acceleration due low fuel pressure.
How do I fix the P0231 fault code?
- First, ensure that your battery voltage is at least 12.6V with the engine off and 13.5V with the engine running. You can fix any issues by doing this before you move on.
- – Check the fuel pump fuse. If the fuse blows, it means there is a short-circuit somewhere in the system. The fuse could blow again if you simply replace it without correcting the short-circuit problem.
- – With the fuel pump relay removed, you should measure at least 4 Ω from the pump to ground. If you measure <4 Ω, you should find and repair the short. You can repeat the test again with the fuel pump off. If the short continues, the problem is between the ground circuit (relay) and the relay. Repair frayed or damaged wires which caused the short circuit.
- – If you get an open circuit of >10 kΩ, the short circuit is in the pump. Take the pump off and measure the resistance between its terminals. If you are measuring less than 4 Ω, replace the pump.
- – Check the fuel pumps relay. For testing purposes, you can use the relays of systems like headlights or wipers. If swapping relays fails, the fuel pump relay may be the problem. Reset the relays if that fails.
- – Inspect the fuel pump wiring and connectors. Repair any broken or melted wires and connectors.
- Replace the fuel pump.
