2021-2024 Audi P045600 Leak Detected TSB

Audi has issued Technical Service Bulletin (TSB) 01 24 41 2071199/4 to address a common issue where the exhaust emissions warning lamp (MIL) illuminates, indicating a 'Very Small Leak Detected' in the vehicle's fuel system. This TSB, which supersedes Group 01 number 24-12 dated March 11, 2024, provides a diagnostic and repair procedure for affected 2021-2024 Audi A4, A4 allroad, S4, A5, A5 Cabriolet, A5 Sportback, S5, S5 Cabriolet, S5 Sportback, RS 5, and RS 5 Sportback models.

Symptoms

Owners of affected Audi vehicles may notice the following symptom:

• The "exhaust emissions warning lamp (MIL) is on."

Fault Codes / DTCs

When the MIL is illuminated for this condition, workshops will find the following Diagnostic Trouble Code (DTC) stored in the vehicle's event memory:

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

This DTC indicates that a very small leak has been detected in the Natural Vacuum Leak Detection (NVLD) system, often related to the fuel tank pressure sender G400.

Diagnosis

The root cause of this Audi A5 P045600 leak is often minor contamination within the fuel tank pressure sender G400 (NVLD). Even the smallest amount of contamination can lead to an internal leak, triggering the DTC P045600. The diagnostic process involves checking the fuel system for leaks according to Guided Fault Finding (GFF) or the Workshop Manual. If GFF specifically instructs the replacement of the fuel tank pressure sender G400 (NVLD), a cleaning procedure is to be performed instead of immediate replacement.

Repair Procedure Summary

The repair procedure outlined in TSB 01 24 41 2071199/4 focuses on cleaning the fuel tank pressure sender G400 (NVLD) rather than replacing it, provided no other relevant fault entries are logged. The steps are as follows:

1. Remove the fuel tank pressure sender G400 (NVLD) as specified in the Workshop Manual.
2. Using a compressed air gun, blow through the NVLD with several brief pressure applications of approximately 5 bar. This is done via a specific opening on the NVLD, as illustrated in Figure 1 of the TSB.
3. Reinstall the fuel tank pressure sender G400 (NVLD) and recheck the system for leaks.

Technicians are also advised to consult Service TV videos in the Audi Knowledge Tank for additional guidance on using a flue gas tester and information on the activated charcoal fuel system/fuel tank leak detection.

Important Warnings

Technicians performing this repair must adhere to the following critical warnings to prevent damage to the NVLD component:

• 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. This procedure is designed to blow out possible contamination.
• While blowing through the component, hold it in your hand. The component must not be clamped or secured in a vice due to the risk of damage.

Warranty Information

For vehicles still under warranty, claims can be submitted using the following codes. If the vehicle is outside of warranty, this TSB is for informational purposes only.

• Service Number: 2041
• Damage Code: 0050

Labor operations for this repair include checking the EVAP system for leaks (2010 0199), removing and reinstalling the NVLD pressure switch (2041 1950), cleaning out the NVLD pressure switch (2041 4999), and potentially charging the battery (2706 8950) or performing GFF (0150 0060).

Owner Action

If your 2021-2024 Audi is displaying the "exhaust emissions warning lamp (MIL) is on" and you suspect an Audi A5 P045600 leak, it is recommended to schedule an appointment with an authorized Audi service center. They will be able to diagnose the specific fault code and perform the necessary cleaning procedure outlined in TSB 01 24 41 2071199/4 to resolve the issue.

NHTSA ID: 11009924