AutoCodes – Infiniti – P1456 Infiniti

P1456 Infiniti Code - Evaporative Emission Control System Leak Detected Small Leak

Quick Answer

This diagnosis detects leaks in the Evaporative Emission (EVAP) purge line using an engine intake manifold vacuum. Common causes include Missing Fuel cap, Incorrect fuel filler cap used, Fuel filler cap remains open or fails to close. 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: P1456 Infiniti indicates Evaporative Emission Control System Leak Detected Small Leak.
Common causes: Common causes include Missing Fuel cap, Incorrect fuel filler cap used, Fuel filler cap remains open or fails to close.
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.

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Code Popularity 23,184

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 Jun 30, 2020

Description
Step-by-Step Diagnostic Guide
Possible Causes
How To Fix
Tech Notes
Cost to Diagnose
Comments
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Code P1456 Infiniti Description

This diagnosis detects leaks in the Evaporative Emission (EVAP) purge line using an engine intake manifold vacuum. If pressure does not increase, the Engine Control Module (ECM) will check for leaks in the line between the fuel tank and EVAP canister purge volume control solenoid valve under the following vacuum test condition.
The vacuum cut valve bypass valve is opened to clear the line between the fuel tank and the EVAP canister purge volume control solenoid valve. The EVAP canister vent control valve will then be closed to shut the EVAP purge line off. The EVAP canister purge volume control solenoid valve is opened to depressurize the EVAP purge line using intake manifold vacuum. After this depressurization is implemented, the EVAP canister purge volume control solenoid valve will be closed.
Most Nissan Models EVAP System Diagram

OBDII Code P1456 Infiniti - Evaporative Emission Control System Leak Detected Small Leak - AutoCodes.com — P1456 Infiniti Code - Evaporative Emission Control System Leak Detected Small Leak

What does this mean?

What are the Possible Causes of the DTC P1456 Infiniti?

Missing Fuel cap
Incorrect fuel filler cap used
Fuel filler cap remains open or fails to close
Foreign matter caught in fuel filler cap
Incorrect fuel tank vacuum relief valve
Leak is in line between intake manifold and EVAP canister purge volume control solenoid valve.

How to Fix the DTC P1456 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 does this mean?

Code Tech Notes

Usually, loose or bad fuel tank filler cap will trigger these codes. Retighten fuel tank filler cap and clear the code to repair the problem. There are several Nissan service bulletins for this problem if tighten the gas cap does not repair the problem, check for Nissan Service bulletins for your model year.

There is an Infiniti Service Bulletin to help diagnose the P1456 code:
Infiniti Factory Service Bulletin OBDII Code P1456

What is the Cost to Diagnose the Code?

Labor: 1.0

To diagnose the P1456 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.