AutoCodes – Ford – P0231 1999 Ford F150

P0231 1999 Ford F150 Code - Fuel Pump Secondary Circuit Low

Quick Answer

The Engine Control Module (ECM) provides ignition positive voltage to the coil side of the fuel pump relay. Common causes include Blown Fuel Pump fuse, Open Fuel Pump Monitor Circuit, Faulty Fuel Pump Relay. 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 Blown Fuel Pump fuse, Open Fuel Pump Monitor Circuit, Faulty Fuel Pump Relay.
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.

Save to My Repairs My Repairs

AI answers can be wrong. Verify repairs with testing. Open full chat

Code Popularity 2,603

How popular is this code, among other codes? Low

Repair Importance Level

Urgent (Diagnose now) (3 / 3)

Repair Difficulty Level

Advanced (Pro) (3 / 3)

What is this?

Table of contents Created and updated by William Orellana on Apr 13, 2019

Description
Possible Causes
How To Fix
Tech Notes
Cost to Diagnose
FAQs
Comments
Add Comment

💬 Need more help? Ask Coddy for instant answers — it's free!

Code P0231 1999 Ford F150 Description

The Engine Control Module (ECM) provides ignition positive voltage to the coil side of the fuel pump relay. When the ignition switch is first turned ON, the ECM energizes the fuel pump relay, which applies power to the fuel pump. The ECM enables the fuel pump relay as long as the engine is cranking or running, and crankshaft reference pulses are received. If no crankshaft reference pulses are received, the ECM de-energizes the fuel pump relay after 2 seconds. The ECM monitors the voltage on the fuel pump relay control circuit.

OBDII Code P0231 1999 Ford F150 - Fuel Pump Secondary Circuit Low - AutoCodes.com — P0231 1999 Ford F150 Code - Fuel Pump Secondary Circuit Low

What does this mean?

What are the Possible Causes of the DTC P0231 1999 Ford F150?

Blown Fuel Pump fuse
Open Fuel Pump Monitor Circuit
Faulty Fuel Pump Relay
Damaged Engine Control Module (ECM)

How to Fix the DTC P0231 1999 Ford F150?

Review the 'Possible Causes' above and visually examine the corresponding wiring harness and connectors. Check for damaged components and inspect connector pins for signs of being broken, bent, pushed out, or corroded.

What does this mean?

Code Tech Notes

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.

What is the Cost to Diagnose the Code?

Labor: 1.0

To diagnose the P0231 1999 Ford F150 code, it typically requires 1.0 hour of labor. Rates vary by location, vehicle, and shop. Many shops charge between $80–$150 per hour; dealerships and metro areas may be higher, independents may be lower.

Need more information about the P0231 1999 Ford F150 code?

Need more information on how to fix the P0231 1999 Ford F150 code? Get Access to Factory Service Manuals

Need Help with the Code?

Get the P0231 1999 Ford F150 code diagnosed by a professional: Find a repair shop in your area

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.