2021-2023 Audi P045600 EVAP Leak TSB

Symptoms of an Audi P045600 EVAP Leak

Owners of affected 2021-2023 Audi vehicles may notice the exhaust emissions warning lamp (MIL) illuminating on their dashboard. This light indicates a potential issue with the vehicle's emissions system.

Fault Codes (DTCs)

When the MIL illuminates, a workshop scan tool may reveal the following diagnostic trouble code (DTC) stored in the vehicle's event memory:

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

This code specifically points to a very small leak within the evaporative emissions (EVAP) system. The TSB notes that no other relevant entries should be logged, and this specific P045600 – "Very Small Leak Detected" code should not have been previously logged for this vehicle.

Technical Background

The root cause of this Audi P045600 EVAP leak is often attributed to the smallest amount of contamination within the fuel tank pressure sender G400, also known as the Natural Vacuum Leak Detection (NVLD) unit. Such contamination can create an internal leak, leading to the system detecting a "Very Small Leak Detected" and setting the P045600 DTC.

Diagnosis and Trigger Conditions

When diagnosing the illuminated MIL and the stored P045600 code, technicians will first ensure there are no other leaks in the fuel system by following the Guided Fault Finding (GFF) procedures or the Workshop Manual. If the GFF system specifically instructs the replacement of the fuel tank pressure sender G400 (NVLD), the repair procedure outlined in TSB 01 23 69 2071199/2 should be followed.

Repair Procedure Summary

The repair detailed in Audi TSB 01 23 69 2071199/2 involves a specific cleaning process for the fuel tank pressure sender G400 (NVLD) rather than immediate replacement. The key steps are:

1. Removal: The fuel tank pressure sender G400 (NVLD) is removed from the vehicle according to the Workshop Manual.
2. Cleaning: Using a compressed air gun, the technician will blow through the NVLD unit with several brief pressure applications of approximately 5 bar. This is done through a specific opening on the NVLD unit, indicated by a green arrow in the technical documentation. This action aims to clear any contamination causing the internal leak.
3. Reinstallation: After the cleaning process, the fuel tank pressure sender G400 (NVLD) is reinstalled.
4. Leak Check: The system is then rechecked for leaks to confirm the repair was successful and the Audi P045600 EVAP leak is resolved.

Important Warnings for Technicians

Audi emphasizes critical precautions during the cleaning process 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."
• "While blowing through the component as described, please hold it in your hand -> the component must not be clamped or secured in a vice (risk of damage)."

Revision History and Superseded Bulletins

This Technical Service Bulletin, 01 23 69 2071199/2, was issued on August 18, 2023, as Revision 2. It supersedes an earlier bulletin, Group 01 number 23-66, which was dated August 9, 2023. The primary reason for this revision was to update the warranty table with additional labor operations.

Owner Action

If you own a 2021-2023 Audi A4, A5, S4, S5, or RS 5 and your exhaust emissions warning lamp (MIL) is illuminated, or you suspect an Audi P045600 EVAP leak, it is recommended to visit an authorized Audi dealership. They can diagnose the issue using the correct procedures and apply the repair outlined in TSB 01 23 69 2071199/2.

Warranty Information

This repair is generally covered under Audi's warranty for up to 48 months or 50,000 miles, whichever comes first. For Certified Pre-Owned (CPO) vehicles, coverage falls under the G10 claim type. If your vehicle is outside of these warranty parameters, this Technical Service Bulletin serves as informational guidance for diagnosis and repair. The service number for this issue is 2041, with a damage code of 0050. Specific labor operations and diagnostic times are provided for dealership claims.

---

Source: NHTSA ID: 10241214