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Engine-Codes – Ford – P0231 1999 Ford F150

P0231 1999 Ford F150 Code - Fuel Pump Secondary Circuit Low

Quick Answer

The P0231 diagnostic trouble code (DTC) for a 1999 Ford F150 indicates a problem with the fuel pump secondary circuit being low. Common causes include Faulty fuel pump relay, Damaged wiring or connectors in the fuel pump circuit, Malfunctioning fuel pump. Severity is High - diagnose this code as soon as possible. Driving is not recommended if the warning light is flashing, the engine runs poorly, or safety-related symptoms are present.

What it means
P0231 1999 Ford F150 indicates Fuel Pump Secondary Circuit Low .
Common causes
Common causes include Faulty fuel pump relay, Damaged wiring or connectors in the fuel pump circuit, Malfunctioning fuel pump.
Severity
High - diagnose this code as soon as possible.
Can I drive?
Driving is not recommended if the warning light is flashing, the engine runs poorly, or safety-related symptoms are present.
What is this?
Table of contents Created and updated by William Orellana on Sep 15, 2024
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Code P0231 1999 Ford F150 Description

The P0231 diagnostic trouble code (DTC) for a 1999 Ford F150 indicates a problem with the fuel pump secondary circuit being low. This means that the voltage in the fuel pump secondary circuit is below the expected range, which can lead to issues with fuel delivery to the engine. The fuel pump secondary circuit is responsible for providing power to the fuel pump relay, which in turn controls the fuel pump's operation. When this circuit is not functioning properly, it can result in poor engine performance, stalling, or even the engine not starting at all.

OBDII Code P0231 1999 Ford F150 - Fuel Pump Secondary Circuit Low
P0231 1999 Ford F150 Code - Fuel Pump Secondary Circuit Low

Common Causes of P0231 1999 Ford F150

  1. Faulty fuel pump relay
  2. Damaged wiring or connectors in the fuel pump circuit
  3. Malfunctioning fuel pump
  4. Issues with the powertrain control module (PCM)
  5. Corrosion or poor connections in the fuel pump circuit

Symptoms of P0231 1999 Ford F150

  1. Engine misfires or runs rough
  2. Difficulty starting the engine
  3. Engine stalling or hesitation during acceleration
  4. Decreased fuel efficiency
  5. Check Engine Light illuminated on the dashboard

How to Fix P0231 1999 Ford F150

  1. Begin by conducting a thorough inspection of the fuel pump relay, wiring, and connectors for any signs of damage or corrosion.
  2. Test the fuel pump relay using a multimeter to determine if it is functioning correctly.
  3. Check the fuel pump's operation by testing its voltage and current draw.
  4. Inspect the powertrain control module (PCM) for any signs of damage or malfunction.
  5. Replace any faulty components, such as the fuel pump relay, damaged wiring, or a malfunctioning fuel pump, as needed.

Cost to Fix P0231 1999 Ford F150

The typical repair costs for addressing a P0231 code on a 1999 Ford F150 can vary depending on the specific cause of the issue. In general, replacing a faulty fuel pump relay or repairing damaged wiring may cost between $100 to $300, including parts and labor. However, if the fuel pump itself needs to be replaced, the total repair cost could range from $300 to $800 or more. It's important to note that diagnosis time and labor rates at auto repair shops can vary, so it's advisable to check local rates for a more accurate estimate.

What does this mean?

Tech Notes for P0231 1999 Ford F150

For some FORD models:

1. Disconnect the inertia switch harness connector

2. Turn key to ON position (Engine OFF)

3. Measure voltage of circuit between inertia switch harness connector and ground

4. If battery voltage is found, replaced Inertia Switch

5. Clear codes



For natural gas applications, the following description applies to the fuel shutoff valve monitor (FSVM) and the fuel shutoff valve power (FSV PWR) circuits.

The PCM monitors the fuel pump monitor (FPM) circuit. The test fails if the PCM commands the fuel pump ON and B+ voltage is not detected on the FPM circuit.

When is the Code Detected?

The code will be set if a low voltage on the control circuit of the fuel pump relay is detected by the ECM.

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About the author: William Orellana is a Master Mechanic and Mechanical Engineer with over 30 years of experience diagnosing and repairing vehicles. Learn more about his background.

Frequently Asked Questions about P0231 1999 Ford F150 Code

1. What are the common symptoms of OBDII code P0231 on a 1999 Ford F150?

- Common symptoms include hard starting, engine stalling, lack of power, and illuminated check engine light.

2. What does OBDII code P0231 indicate on a 1999 Ford F150?

- Code P0231 indicates a low voltage condition in the fuel pump secondary circuit.

3. What are the possible causes of OBDII code P0231 on a 1999 Ford F150?

- Possible causes include a faulty fuel pump relay, damaged wiring, poor electrical connections, or a malfunctioning fuel pump driver module.

4. How can I diagnose the cause of OBDII code P0231 on my 1999 Ford F150?

- Use a multimeter to test the fuel pump relay, inspect wiring for damage, check electrical connections, and test the fuel pump driver module for functionality.

5. Can a faulty fuel pump cause OBDII code P0231 on a 1999 Ford F150?

- Yes, a faulty fuel pump can lead to a low voltage condition in the fuel pump secondary circuit, triggering code P0231.

6. How can I repair OBDII code P0231 on my 1999 Ford F150?

- Repair options include replacing the fuel pump relay, repairing damaged wiring, ensuring proper electrical connections, or replacing the fuel pump driver module if necessary.

7. Is it safe to continue driving with OBDII code P0231 on a 1999 Ford F150?

- It is not recommended to drive with code P0231 as it can lead to engine stalling and potential safety hazards. It's best to address the issue promptly.

8. Can a DIY enthusiast fix OBDII code P0231 on a 1999 Ford F150?

- Depending on your skills and tools, you may be able to diagnose and repair code P0231 yourself by following proper diagnostic procedures and using the right replacement parts.

9. How much does it typically cost to repair OBDII code P0231 on a 1999 Ford F150?

- The cost of repairing code P0231 can vary depending on the underlying cause. Costs may include parts such as a fuel pump relay or fuel pump driver module, as well as labor if professional assistance is needed.

10. Will resetting the check engine light resolve OBDII code P0231 on a 1999 Ford F150?

- Simply resetting the check engine light will not fix the underlying issue causing code P0231. It's important to diagnose and address the root cause of the problem to prevent further issues.

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