2021-2024 Audi A5 MIL On P045600 NVLD Leak Detected TSB

Symptoms

Owners of 2021-2024 Audi A4, A4 allroad, S4, A5, A5 Cabriolet, A5 Sportback, S5, S5 Cabriolet, S5 Sportback, RS 5, and RS 5 Sportback vehicles may experience the exhaust emissions warning lamp (MIL) is on.

Fault Codes / DTCs

When the exhaust emissions warning lamp illuminates, a diagnostic scan may reveal the following fault code stored in the vehicle's event memory:

• DTC P045600 (P0456) – "Very Small Leak Detected"

It is important to note that no other relevant entries should be logged, and the DTC P045600 – Very Small Leak Detected should not have been previously logged for the vehicle to qualify for this specific repair procedure.

Technical Background

The primary cause for the Audi A5 P045600 fault code is often the smallest contamination within the fuel tank pressure sender G400, which is part of the Natural Vacuum Leak Detection (NVLD) system. This contamination can create an internal leak, triggering the "Very Small Leak Detected" message and illuminating the Check Engine Light.

Important Warnings

Audi has issued specific warnings regarding the repair procedure for the NVLD system to prevent further damage:

• "The opening marked with a red circle (Figure 1) must not be closed or exposed to compressed air, as this may cause irreparable damage to the NVLD. In addition, this ensures that possible contamination can be blown out of the NVLD."
• "While blowing through the component as described above, please hold it in your hand → the component must not be clamped or secured in a vice due to risk of damage."

Repair Procedure Summary

The repair for the Audi A5 P045600 issue, as detailed in TSB 2071199/3, focuses on cleaning the fuel tank pressure sender G400 (NVLD) rather than immediate replacement. The process involves several key steps:

1. System Check: A technician will first ensure there are no other leaks in the fuel system by following the Guided Fault Finding (GFF) or Workshop Manual procedures.
2. Component Removal: If GFF indicates a need to address the G400 (NVLD) sender, it will be carefully removed according to the Workshop Manual.
3. Cleaning the NVLD: Using a compressed air gun, the technician will blow through the NVLD (specifically item 12 in the provided illustration) with several brief applications of approximately 5 bar of pressure. This action is designed to clear any contamination.
4. Reinstallation and Verification: After cleaning, the fuel tank pressure sender G400 (NVLD) is reinstalled, and the system is rechecked for any leaks to confirm the repair's effectiveness.

Technicians may also consult Service TV videos available in the Audi Knowledge Tank for additional guidance on flue gas testing and activated charcoal fuel system leak detection.

Warranty Information

This repair is typically covered under warranty for vehicles up to 48 months or 50,000 miles. For Audi Certified Pre-Owned (CPO) vehicles, coverage is also available (Claim Type G10). If the vehicle falls outside these warranty parameters, the Technical Service Bulletin serves as informational guidance.

Warranty claims for this procedure use Service Number 2041 and Damage Code 0050. Specific labor operations include:

• Check EVAP system for leaks: Labor operation 2010 0199 (20 Time Units)
• NVLD pressure switch remove + reinstall: Labor operation 2041 1950
• Clean out NVLD pressure switch: Labor operation 2041 4999 (10 Time Units)

Diagnostic time (GFF 0150 0000) is allowed up to a maximum of 50 Time Units. Road tests before and after the service procedure are not allocated separate time units.

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Source: NHTSA ID: 10251617