2021-2022 Nissan EVAP Leak DTC P0456 TSB

Nissan has issued Technical Bulletin NTB17-082E to address a common issue causing the check engine light to illuminate with Diagnostic Trouble Code (DTC) P0456. This bulletin, last amended on February 7, 2022, provides guidance for technicians on diagnosing and repairing an EVAP (Evaporative Emission Control System) leak specifically related to the vent control valve O-ring.

The EVAP system is crucial for preventing fuel vapors from escaping into the atmosphere. A leak in this system, even a very small one, can trigger the check engine light and indicate a potential environmental concern.

Symptoms

Owners of affected 2021-2022 Nissan vehicles may notice the following symptom:

• The Malfunction Indicator Lamp (MIL), commonly known as the check engine light, is illuminated on the dashboard.

Fault Codes / DTCs

When scanned, the vehicle's onboard diagnostic system will typically show:

• P0456: "EVAP VERY SML LEAK" (Evaporative Emission System Leak Detected - Very Small Leak)

Diagnosis / Trigger Conditions

To confirm the Nissan P0456 EVAP leak issue, technicians will perform a diagnostic procedure. It's important to first rule out other common causes for a P0456 code. Specifically, the bulletin states that the DTC P0456 should not be caused by a loose fuel fill cap. If a loose fuel cap is the cause, a different bulletin (NTB13-097) would apply.

Once a loose fuel cap is ruled out, the diagnosis focuses on the EVAP system. Technicians will look for an EVAP leak detected where the vent control valve mounts to the canister. If this specific leak point is identified, and the vent control valve O-ring seal is determined to be the root cause, then the repair outlined in this bulletin is applicable.

Important Warnings

Owners and technicians should be aware of a critical detail regarding this repair:

• The vent control valve O-ring seal (O-ring) is no longer available as a service part. This means that the O-ring cannot be purchased or replaced individually.

Repair Procedure Summary

The repair for a Nissan P0456 EVAP leak involves replacing the entire vent control valve assembly. Since the O-ring is not available separately, the complete valve assembly must be installed to resolve the leak. Technicians are instructed to refer to the applicable Electronic Service Manual (ESM) for the detailed replacement procedure, ensuring all steps are followed correctly for a successful repair.

Owner Action

If your 2021-2022 Nissan vehicle displays a check engine light and you suspect a Nissan P0456 EVAP leak, it is recommended to visit an authorized Nissan dealership or a qualified service center. They have the necessary diagnostic tools and access to the Electronic Service Manual to accurately diagnose the issue and perform the correct repair. Do not attempt to replace just the O-ring, as it is not available as a standalone part.

Source: NHTSA ID 10208953