p0231 code 7.3 Powerstroke: How To Fix p0231 code Issue

The P0231 Diagnostic Trouble Code is common with 7.3 and 6.0 Powerstroke and relates to the fuel system. If you own a 7.3 Powerstroke truck, it is important to know what the p0231 code 7.3 Powerstroke means. 

To help you better diagnose the source of this trouble code, let’s look into what the code actually means, its common causes, and how to fix it. 

What Does p0231 code 7.3 Powerstroke Mean?

The full code will be displayed as a p0231 low voltage fuel pump secondary circuit. So what does it mean? To understand the meaning of this code, we need first to know how the fuel pump works.

In the modern version of the 7.3, the fuel pump and injectors are electrically operated, meaning some fuses and relays deliver power to the fuel pump. The engine control module or ECM typically grounds the fuel pump relay.

p0231 code 7.3 Powerstroke

The relay directs power to the fuel pump through the secondary circuit. If there is insufficient voltage to pressurize the fuel pump, a DTC p023 low voltage fuel pump secondary circuit will be returned. Therefore this trouble code is caused by a low voltage to the fuel pump

Common Causes Of p0231 code Appears in 7.3 Powerstroke

There are several reasons you may be getting the p0231 code in your 7.3 Powerstroke, the most common being the following.

Faulty Fuel Pump Relays:

The fuel pump relays are used to send power to the fuel pump; if they are faulty, no power or voltage will be sent to the fuel pump resulting in the p0231 code.

Damage To The Harness:

if the wiring harness going to the fuel pump is damaged, it can cause corrosion, broken wires, partly broken wires, or contact with the body or chassis. This will also result in a p0231 code.

Blown Fuel Pump Fuse:

blown fuel pump fuses will indicate an open circuit in the harness and result in a p0231 code. 

Open Feedback Circuit:

When there is an open circuit or corrosion in the monitor circuit to the ECM, the latter will not detect the fuel pump operation causing the relay to shut off. This results in zero voltage to the pump causing the p0231 code.

Inertia Switch Activated:

The inertia switch works to open the fuel pump circuit in the event of an accident. This prevents fuel from leaking on the vehicle or ground. This is usually a fire prevention measure. However, when it is activated even by a slight impact, it interrupts the flow to the fuel pump and the ECM monitor, causing the p0231 code.

P0231 Code Symptoms In The 7.3 Powerstroke

What are some visible signs you will notice when you get this code? 

Engine Not Starting:

The most notable sign is the engine does not start when you turn on the ignition. 

Engine Stalling:

Another common symptom is when driving, the car suddenly loses power and shuts off. In some cases, the engine cranks up again after a few minutes.

Insufficient Fuel Supply:

another symptom is you may notice low fuel being supplied to the engine. 

How To Diagnose The P0231 Code On Your 7.3 Powerstroke?

The p0231 code 7.3 Powerstroke can be caused by various issues, as we have already seen. So diagnosing the problem will involve checking different parts of the fuel system and the battery. 

Check Battery Voltage:

You will first want to check that the battery has at least 12.6 volts when the engine is off, and when it is on, it should have at least 13.5 volts. 

Check The Fuel Pump Fuses:

Replacing the fuel pump fuse when you notice that it is blown may not fix the problem. More often than not, the fuel pump fuse will get blown due to an open circuit. 

Use a voltmeter to check for an open circuit and remove the fuel pump relay. Next, use the voltmeter to measure the pump to the ground. You should get at least 4 ohms; if you get a reading below 4 ohms, you have a short circuit that needs fixing.

Repeat this test with the fuel pump disconnected. If the results are the same, the short circuit may be between the relay and the ground. In this regard, check for any chafed wiring or poorly installed aftermarket wiring. 

Next, measure the resistance on the terminals while the fuel pump is disconnected. If you get a reading of less than 4 ohms, the fuel pump may be faulty and need replacing.

Check The Fuel Pump Relay:

To diagnose the fuel pump relay, replace it with the one you know is working. This can be the wipers or headlights relay. Alternatively, you can test the relay by powering the primary circuit and checking the resistance in the secondary circuit.

If the relay you have swapped with works, mark the one you removed as that is the one that needs replacing. If the relay you have swapped with doesn’t work, return them to their original location.

Check The Relay Inputs And Outputs

The fuel pump typically has two terminals of the fuel pump relay which should have power. There are two others that go to the ground. Check for resistance to ground on the secondary circuit of the fuel pump. You should get a reading of 4 to 6 ohms. 

Check The Fuel Pump Monitor

Check if there is any continuity between the fuel pump relay secondary circuit and the ECM. Do this with the ECM disconnected. Check for broken or corroded wires if you get a resistance reading greater than 0 ohms. 

Common Mistakes When Diagnosing The P0231 Code On Your 7.3 Powerstroke

  • Replacing parts without Testing: The DTC relates to the fuel system and pump; some people will simply replace the pump without checking. This is not the way to go, as simply replacing the fuel pump may not fix the issue.
  • Replacing Blown Fuses: Also, when you detect a blown fuel pump fuse, do not replace it first before inspecting the wiring harness for an open circuit.

What Will Happen If You Do Not Fix The P0231 Code On Your 7.3 Powerstroke

This code indicates a problem with your fuel system and, if not fixed, can lead to more serious issues. Also, you can not start with this error, and fixing it will be the only way to get your car back on the road. 

Frequently Asked Questions About p0231 code

What Causes continuous P0231 DTC

When you get this DTC continuously, it may be caused by damaged or chafed wiring to the fuel pump.

How Much Does It Cost To Fix P0231 DTC?

Depending on the problem’s severity, the repair cost can be anywhere between $50 and $100. 

Where Is The Fuel Pump Relay Located in 7.3 Powerstroke

The relays in a Powerstroke engine are located inside the relay control panel. This panel is located on the right side of the engine between the battery and the driver’s side strut tower. The relay panel is usually a black plastic box with a diagram of all relays on top.


The p0231 code 7.3 Powerstroke is a general DTC that does not relate to one specific fuel system part. It can be caused by a variety of issues, and this is why it can be challenging to diagnose. Nevertheless, check all the parts before replacing any parts when you get this DTC.

Last Updated on February 3, 2023 by Rifen

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