AutoCodes – Nissan – P0400 Nissan

P0400 Nissan Code - Exhaust Gas Recirculation Function- No/Low Flow Detected

Quick Answer

Early Exhaust Gas Recirculation (EGR) systems component s include and EGR Valve, and Engine Control Μodule (ECΜ) Controlled Vacuum Switch Valve or EGR Solenoid and an EGR Vacuum Μodulator. 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 Nissan indicates Exhaust Gas Recirculation Function- No/Low Flow Detected.
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 78,991

How popular is this code, among other codes? Medium

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 May 30, 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 Nissan Description

Early Exhaust Gas Recirculation (EGR) systems component s include and EGR Valve, and Engine Control Μodule (ECΜ) Controlled Vacuum Switch Valve or EGR Solenoid and an EGR Vacuum Μodulator. Depending on the engine and driving conditions, the ECΜ will control the EGR Solenoid which will operate the EGR Vacuum Μodulator 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 ECΜ. 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 ECΜ does not issue the pulse signal. Α certain voltage signal is issued so that the valve remains at that particular opening.

OBDII Code P0400 Nissan - Exhaust Gas Recirculation Function- No/Low Flow Detected - AutoCodes.com — P0400 Nissan Code - Exhaust Gas Recirculation Function- No/Low Flow Detected

What does this mean?

What are the Possible Causes of the DTC P0400 Nissan?

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 Nissan?

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 most likely cause of this problem is a clogged EGR valve or EGR flow passages. Before replacing any parts, try cleaning the EGR valve, tube, and passages with throttle body or carburetor cleaner. Also, check for damage or loose vacuum hoses to the EGR valve.

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What is the Cost to Diagnose the Code?

Labor: 1.0

To diagnose the P0400 Nissan 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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Information for Specific Nissan Models

P0400 1998 Nissan Altima Sedan — Exhaust Gas Recirculation Function No/Low Flow Detected
P0400 1999 Nissan Altima Sedan — Exhaust Gas Recirculation Function No/Low Flow Detected
P0400 2000 Nissan Altima Sedan — Exhaust Gas Recirculation Function No/Low Flow Detected
P0400 2001 Nissan Altima Sedan — Exhaust Gas Recirculation Function No/Low Flow Detected
P0400 2004 Nissan Maxima — Exhaust Gas Recirculation Function- No/Low Flow Detected
P0400 2005 Nissan Maxima — Exhaust Gas Recirculation Function- No/Low Flow Detected
P0400 2006 Nissan Maxima — Exhaust Gas Recirculation Function- No/Low Flow Detected
P0400 2002 Nissan Sentra — Exhaust Gas Recirculation Function- No/Low Flow Detected
P0400 2003 Nissan Sentra — Exhaust Gas Recirculation Function- No/Low Flow Detected
P0400 2004 Nissan Sentra — Exhaust Gas Recirculation Function- No/Low Flow Detected
P0400 2005 Nissan Sentra — Exhaust Gas Recirculation Function- No/Low Flow Detected
P0400 2006 Nissan Sentra — Exhaust Gas Recirculation Function- No/Low Flow Detected

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 Nissan Code

1. What are the common symptoms of OBDII code P0400 in a Nissan?

The common symptoms include rough idling, hesitation during acceleration, decreased fuel efficiency, and the illumination of the Check Engine Light.

2. What are the typical causes of OBDII code P0400 in a Nissan?

Common causes of P0400 in a Nissan include a faulty EGR valve, clogged EGR passages, wiring issues, or a malfunctioning EGR temperature sensor.

3. How can I diagnose the cause of OBDII code P0400 in my Nissan?

To diagnose P0400, you can perform a visual inspection of the EGR system, check the EGR valve operation, test the EGR temperature sensor, and inspect for any clogged passages or hoses.

4. Can a clogged catalytic converter trigger OBDII code P0400 in a Nissan?

While a clogged catalytic converter can cause similar symptoms, it is not a direct cause of P0400. It's essential to diagnose the specific EGR system components for this code.

5. How can I repair OBDII code P0400 in my Nissan?

Repair options for P0400 include cleaning or replacing the EGR valve, clearing clogged passages, fixing wiring issues, or replacing the EGR temperature sensor as needed.

6. Is it safe to continue driving my Nissan with OBDII code P0400?

It's generally not recommended to drive with an unresolved P0400 code, as it can lead to decreased performance and potentially cause further damage to the engine over time.

7. Can a dirty air filter trigger OBDII code P0400 in a Nissan?

While a dirty air filter can impact engine performance, it is not a direct cause of P0400. Focus on diagnosing and repairing the EGR system components for this specific code.

8. Will disconnecting the EGR system fix OBDII code P0400 in my Nissan?

Disconnecting the EGR system may temporarily prevent the code from triggering, but it is not a recommended or permanent solution. Proper diagnosis and repair are necessary.

9. How much does it typically cost to repair OBDII code P0400 in a Nissan?

The cost of repairing P0400 can vary depending on the specific issue, parts needed, and labor rates. It's advised to consult with a mechanic for an accurate estimate.

10. Can a bad PCV valve cause OBDII code P0400 in a Nissan?

A faulty PCV valve is not a common cause of P0400. Focus on inspecting and repairing the EGR system components to address this specific code.