2021-2022 Nissan EVAP Leak DTC P0442, P0455, P0456

Nissan has issued Technical Bulletin NTB13-097J to provide diagnostic information for EVAP (Evaporative Emission Control System) leak Diagnostic Trouble Codes (DTCs) P0442, P0455, and P0456. These codes are frequently triggered by a simple issue: a loose fuel filler cap. This bulletin helps technicians properly diagnose the root cause to avoid unnecessary parts replacement.

Symptoms

Owners of affected 2021-2022 Nissan vehicles may notice a warning indicator in the instrument cluster alerting them to a loose fuel filler cap. This warning typically displays as a "LOOSE FUEL CAP" message or light. If the fuel filler cap remains loose for multiple trips, the Malfunction Indicator Lamp (MIL) will illuminate, and the EVAP leak DTCs P0442, P0455, or P0456 will be stored in the vehicle's computer system.

Fault Codes / DTCs

The following Diagnostic Trouble Codes (DTCs) are associated with EVAP system leaks, which can often be caused by a loose fuel filler cap:

• P0442: Evaporative Emission Control System Leak Detected (Small Leak)
• P0455: Evaporative Emission Control System Leak Detected (Gross Leak)
• P0456: Evaporative Emission Control System Leak Detected (Very Small Leak)

These codes indicate that the EVAP system is not maintaining the expected pressure, suggesting a leak somewhere in the system. The most common and easily rectifiable cause for a Nissan EVAP leak P0442, P0455, or P0456 is an improperly secured fuel cap.

Important Warnings for Owners

Nissan has provided crucial advisories for both owners and technicians regarding these EVAP leak DTCs:

• Immediate Action: If your vehicle displays a "LOOSE FUEL CAP" warning light or message, you should safely stop the vehicle and ensure the fuel filler cap is installed correctly. Refer to your vehicle's Owner's Manual for specific instructions on proper fuel filler cap installation and the warning system.
• Diagnosis is Key: For technicians, the bulletin explicitly states that a test drive is not part of the DTC confirmation or diagnostic procedures for these codes, and performing one will only waste time. The diagnostic procedure outlined in the bulletin must be used for an effective repair.
• Avoid Unnecessary Replacements: If diagnosis confirms that the MIL illuminated due to a loose fuel filler cap and no actual EVAP leak is detected, technicians are instructed to DO NOT REPLACE FUEL FILLER CAP OR ANY OTHER EVAP RELATED PARTS. Any parts replaced under warranty for these DTCs are subject to automatic return to Nissan for inspection, and functional parts will result in a charge-back to the dealer.
• Professional Service: Nissan Bulletins are intended for use by qualified technicians, not 'do-it-yourselfers'. If you suspect this condition applies to your vehicle, consult your Nissan dealer for diagnosis.

Diagnosis and Repair Procedure Summary

The diagnostic process for a Nissan EVAP leak P0442, P0455, or P0456 begins by checking for stored DTCs. If P0442, P0455, or P0456 are present, the technician will follow a specific flow chart:

1. Confirm Fuel Filler Cap Security: The first step is to ensure the fuel filler cap is securely tightened.
2. EVAP System Leak Check: Technicians will use the essential tool J-42909 to perform an EVAP system leak check. This involves connecting the tool, using an Active Test to close the vent control valve, applying pressure until a specific bar graph reading is achieved, and then monitoring the pressure for 10 minutes.
   • For models with a service port (2017 and older), the tool connects directly to the service port (as shown in Figure 2 of the bulletin).
   • For models without a service port (2018 and newer), the EVAP line is disconnected at the purge control valve, and the tool is connected there (as shown in Figure 3 of the bulletin). In this case, the tool is also used to check for a separate purge control valve leak.
3. Evaluate Results: If the bar graph remains stable and no purge control valve leak is detected, it indicates that no EVAP leak is present at that time. The MIL was likely triggered by the fuel filler cap not being properly secured. In this scenario, the DTCs are erased, and the customer is advised to always ensure the fuel filler cap is properly secured.
4. Actual EVAP Leak: If an EVAP leak is detected during the test, the bulletin states that it does not apply to this specific condition, and further diagnosis using ASIST and the applicable Electronic Service Manual is required.

This procedure is designed to quickly identify if the issue is a simple loose fuel cap or a more complex EVAP system problem, preventing unnecessary repairs.

Required Tools

For proper diagnosis of a Nissan EVAP leak P0442, P0455, or P0456, the following essential tool is required:

• J-42909: This specialized tool is used for EVAP system leak checks and pressure application.

Owner Action

If you experience a "LOOSE FUEL CAP" warning or your Malfunction Indicator Lamp (MIL) illuminates with DTCs P0442, P0455, or P0456, the first step is to ensure your fuel filler cap is securely tightened. If the warning persists or returns, or if the MIL remains illuminated, it is recommended to visit your authorized Nissan dealer. They have the necessary tools and diagnostic procedures outlined in Technical Bulletin NTB13-097J to accurately diagnose the problem and perform any required repairs, ensuring you avoid unnecessary parts replacement.