AutoCodes – Infiniti – P0402 Infiniti

P0402 Infiniti Code - Exhaust Gas Recirculation Flow Excessive Detected

Quick Answer

The Engine Control Module (ECM) monitors the switching frequency ratio of heated oxygen sensors 1 and 2. Common causes include EGR volume control valve stuck open, Faulty EGR volume control valve, EGR solenoid valve harness is open or shorted. 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: P0402 Infiniti indicates Exhaust Gas Recirculation Flow Excessive Detected.
Common causes: Common causes include EGR volume control valve stuck open, Faulty EGR volume control valve, EGR solenoid valve harness is open or shorted.
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 8,112

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 Mar 30, 2024

Description
Possible Causes
How To Fix
Cost to Diagnose
FAQs
Comments
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Code P0402 Infiniti Description

The Engine Control Module (ECM) monitors the switching frequency ratio of heated oxygen sensors 1 and 2. If too much Exhaust Gas Recirculation (EGR) flow exists due to an EGRC-BPT valve malfunction, off idle engine roughness will increase. If the roughness is large, then the vacuum to the EGR valve is interrupted through the EGRC solenoid valve. If the engine roughness is reduced at that time, the EGRC-BPT valve malfunction is indicated.

OBDII Code P0402 Infiniti - Exhaust Gas Recirculation Flow Excessive Detected - AutoCodes.com — P0402 Infiniti Code - Exhaust Gas Recirculation Flow Excessive Detected

What does this mean?

What are the Possible Causes of the DTC P0402 Infiniti?

EGR volume control valve stuck open
Faulty EGR volume control valve
EGR solenoid valve harness is open or shorted
EGR solenoid valve circuit poor electrical connection
Faulty EGR temperature sensor and circuit

How to Fix the DTC P0402 Infiniti?

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 is the Cost to Diagnose the Code?

Labor: 1.0

To diagnose the P0402 Infiniti 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 P0402 Infiniti Code

1. What are the common symptoms of OBDII code P0402 in an Infiniti?

- Common symptoms include poor engine performance, rough idle, decreased fuel efficiency, and the illumination of the check engine light.

2. What are the possible causes of OBDII code P0402 in an Infiniti?

- Potential causes include a faulty EGR valve, clogged EGR passages, carbon buildup, wiring issues, or a malfunctioning EGR temperature sensor.

3. How can I diagnose the source of OBDII code P0402 in my Infiniti?

- Diagnosing the code involves checking the EGR valve for proper operation, inspecting the EGR passages for blockages, testing the EGR temperature sensor, and verifying the integrity of related wiring.

4. Can a dirty air filter cause OBDII code P0402 in an Infiniti?

- While a dirty air filter may not directly cause P0402, it can contribute to carbon buildup in the EGR system, potentially leading to issues triggering the code.

5. How can I prevent OBDII code P0402 from coming back after repairs in my Infiniti?

- Regular maintenance, such as cleaning the EGR system, using high-quality fuel, and addressing engine performance issues promptly, can help prevent the recurrence of P0402.

6. Is it safe to continue driving with OBDII code P0402 present in my Infiniti?

- It is generally not recommended to drive with code P0402 present, as it can lead to further engine damage and decreased fuel efficiency if left unresolved.

7. What are some DIY repair tips for fixing OBDII code P0402 in an Infiniti?

- DIY repair tips include cleaning the EGR valve and passages, checking and replacing the EGR temperature sensor if needed, and ensuring all related wiring is in good condition.

8. Can a malfunctioning EGR valve cause other issues besides triggering OBDII code P0402 in an Infiniti?

- Yes, a faulty EGR valve can also lead to engine knocking, rough idling, decreased power, and increased emissions if not addressed promptly.

9. Are there any software updates or recalls related to OBDII code P0402 for Infiniti vehicles?

- It is recommended to check with your local Infiniti dealership or service center to inquire about any software updates or recalls related to code P0402 for your specific vehicle model.

10. How long does it typically take to repair OBDII code P0402 in an Infiniti?

- The repair time for code P0402 can vary depending on the exact cause and complexity of the issue. It can range from a quick fix like cleaning the EGR system to more involved repairs that may take several hours to complete.