AutoCodes – Isuzu – P0402 Isuzu

P0402 Isuzu Code - Exhaust Gas Recirculation Flow Excessive Detected

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 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 Isuzu 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 10,651

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
Possible Causes
How To Fix
Cost to Diagnose
FAQs
Comments
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Code P0402 Isuzu 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 P0402 Isuzu - Exhaust Gas Recirculation Flow Excessive Detected - AutoCodes.com — P0402 Isuzu Code - Exhaust Gas Recirculation Flow Excessive Detected

What does this mean?

What are the Possible Causes of the DTC P0402 Isuzu?

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 Isuzu?

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 Isuzu 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 Isuzu Code

1. What does the OBDII code P0402 mean on an Isuzu?

P0402 indicates that the Exhaust Gas Recirculation (EGR) system is detecting excessive flow, which can impact engine performance and emissions.

2. What are the common symptoms of code P0402 on an Isuzu?

Symptoms may include rough idling, reduced fuel efficiency, engine hesitation, increased exhaust emissions, or the Check Engine Light being illuminated.

3. What causes the P0402 code on an Isuzu?

Common causes include a stuck-open EGR valve, carbon buildup in the EGR system, a faulty EGR sensor, or issues with the EGR control solenoid or wiring.

4. Can I drive my Isuzu with a P0402 code?

While the vehicle may still be drivable, prolonged operation with this code can lead to performance issues, increased emissions, and potential engine damage.

5. How can I fix the P0402 code on my Isuzu?

Start by inspecting and cleaning the EGR valve and passages. If the issue persists, test the EGR valve, sensor, and solenoid for proper operation and replace faulty components as needed.

6. How do I know if my EGR valve is the problem for code P0402?

A stuck-open or malfunctioning EGR valve is a common culprit. If cleaning does not resolve the issue, the valve may need to be replaced.

7. Can a vacuum leak cause the P0402 code on an Isuzu?

Yes, a vacuum leak in the EGR system can lead to excessive EGR flow and trigger the P0402 code.

8. How much does it cost to repair the P0402 code on an Isuzu?

The cost varies depending on the issue. Cleaning an EGR valve is inexpensive, while replacing the valve or other components can cost $150â€“$500, including labor.

9. Will a clogged catalytic converter cause the P0402 code on my Isuzu?

While not common, a partially clogged catalytic converter could create exhaust backpressure, contributing to excessive EGR flow and triggering the P0402 code.

10. How do I prevent the P0402 code from recurring on my Isuzu?

Perform regular maintenance, including cleaning the EGR valve and passages, and promptly address any related engine performance issues to prevent excessive carbon buildup.