AutoCodes – Ford – P0400 1999 Ford F150

P0400 1999 Ford F150 Code - Exhaust Gas Recirculation Flow

Quick Answer

Early Exhaust Gas Recirculation (EGR) systems component s include and EGR Valve, and Engine Control Îœodule (ECÎœ) Controlled Vacuum Switch Valve or EGR Solenoid and an EGR Vacuum Îœodulator. Common causes include Exhaust Gas Recirculation (EGR) volume control valve stuck closed, Faulty Exhaust Gas Recirculation (EGR) volume control solenoid valve, Faulty EGR Valve. Severity is Moderate - service should be scheduled soon. The vehicle may still be drivable for short trips if it runs normally, but avoid hard driving and repair it soon.

What it means: P0400 1999 Ford F150 indicates Exhaust Gas Recirculation Flow.
Common causes: Common causes include Exhaust Gas Recirculation (EGR) volume control valve stuck closed, Faulty Exhaust Gas Recirculation (EGR) volume control solenoid valve, Faulty EGR Valve.
Severity: Moderate - service should be scheduled soon.
Can I drive?: The vehicle may still be drivable for short trips if it runs normally, but avoid hard driving and repair it soon.

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Code Popularity 2,713

How popular is this code, among other codes? Low

Repair Importance Level

Moderate (Service soon) (2 / 3)

Repair Difficulty Level

Intermediate (2 / 3)

What is this?

Table of contents Created and updated by William Orellana on Jun 14, 2020

Description
Step-by-Step Diagnostic Guide
Possible Causes
How To Fix
Tech Notes
Cost to Diagnose
FAQs
Comments
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Code P0400 1999 Ford F150 Description

Early Exhaust Gas Recirculation (EGR) systems component s include and EGR Valve, and Engine Control Îœodule (ECÎœ) Controlled Vacuum Switch Valve or EGR Solenoid and an EGR Vacuum Îœodulator. Depending on the engine and driving conditions, the ECÎœ will control the EGR Solenoid which will operate the EGR Vacuum Îœodulator to regulate the opening and closing of the EGR Valve.
The EGR system on recently built vehicles uses a step motor to control the flow rate of EGR from exhaust manifold. This motor has four winding phases. It operates according to the output pulse signal of the ECÎœ. Two windings are turned ON and OFF in sequence. Each time an ON pulse is issued, the valve opens or closes, changing the flow rate. When no change in the flow rate is needed, the ECÎœ does not issue the pulse signal. Î‘ certain voltage signal is issued so that the valve remains at that particular opening.

OBDII Code P0400 1999 Ford F150 - Exhaust Gas Recirculation Flow - AutoCodes.com — P0400 1999 Ford F150 Code - Exhaust Gas Recirculation Flow

What does this mean?

What are the Possible Causes of the DTC P0400 1999 Ford F150?

Exhaust Gas Recirculation (EGR) volume control valve stuck closed
Faulty Exhaust Gas Recirculation (EGR) volume control solenoid valve
Faulty EGR Valve
Faulty EGR temperature sensor and circuit
Exhaust Gas Recirculation (EGR) solenoid valve harness is open or shorted
Exhaust Gas Recirculation (EGR) solenoid valve circuit poor electrical connection
Dead (Weak) battery

How to Fix the DTC P0400 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

The EEGR system is monitored once per drive cycle during steady state conditions above 48 mph . The test will fail when a malfunction is detected by PCM calculations indicating the EGR flow is less or greater than expected.

EGR flow malfunction could be caused by a clogged EGR valve or EGR tube. Before replacing any parts try cleaning the EGR valve, tube and passages.

What is the Cost to Diagnose the Code?

Labor: 1.0

To diagnose the P0400 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.

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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 P0400 1999 Ford F150 Code

1. What are the common symptoms of OBDII code P0400 on a 1999 Ford F150?

The common symptoms of P0400 on a 1999 Ford F150 include rough idling, decreased fuel efficiency, engine hesitation, and the illumination of the check engine light.

2. What does OBDII code P0400 indicate on a 1999 Ford F150?

OBDII code P0400 on a 1999 Ford F150 indicates a problem with the Exhaust Gas Recirculation (EGR) flow. It means that the EGR system is not functioning as it should.

3. What are the possible causes of OBDII code P0400 on a 1999 Ford F150?

Possible causes of P0400 on a 1999 Ford F150 include a faulty EGR valve, clogged EGR passages, a malfunctioning EGR sensor, or a wiring issue in the EGR system.

4. How can I diagnose the cause of OBDII code P0400 on my 1999 Ford F150?

To diagnose the cause of P0400, you can start by checking the EGR valve for proper operation, inspecting the EGR passages for blockages, testing the EGR sensor, and examining the wiring for any damage or loose connections.

5. Can I drive my 1999 Ford F150 with OBDII code P0400?

It is not recommended to drive your 1999 Ford F150 with OBDII code P0400 for an extended period as it can lead to other issues and potentially cause damage to the engine. It's best to address the problem as soon as possible.

6. How can I repair OBDII code P0400 on my 1999 Ford F150?

To repair P0400 on your 1999 Ford F150, you may need to clean or replace the EGR valve, clear any blockages in the EGR passages, replace the EGR sensor if necessary, and ensure the wiring in the EGR system is in good condition.

7. Are there any DIY tips for fixing OBDII code P0400 on a 1999 Ford F150?

Some DIY tips for fixing P0400 on a 1999 Ford F150 include cleaning the EGR valve with a suitable cleaner, using a vacuum gauge to test EGR valve operation, and visually inspecting the EGR passages for obstructions.

8. What happens if I ignore OBDII code P0400 on my 1999 Ford F150?

Ignoring OBDII code P0400 on your 1999 Ford F150 can lead to decreased engine performance, reduced fuel efficiency, and potential damage to engine components over time. It's best to address the issue promptly.

9. Can a clogged catalytic converter cause OBDII code P0400 on a 1999 Ford F150?

While a clogged catalytic converter can affect EGR flow and trigger code P0400, the primary causes are usually related to the EGR system itself, such as a faulty EGR valve or blocked passages.

10. How much does it typically cost to fix OBDII code P0400 on a 1999 Ford F150?

The cost to fix P0400 on a 1999 Ford F150 can vary depending on the exact cause of the issue and whether you choose to repair it yourself or take it to a professional. Costs may range from around $100 for a DIY repair to a few hundred dollars at a repair shop.