2024-2025 Audi Fuel Cap Seal Leaking TSB 2078916/1

Audi has released Technical Service Bulletin (TSB) 2078916/1 to address a common issue affecting various 2024-2025 Audi models: a leaking fuel tank cap seal. This condition can trigger warning lights on the instrument cluster and store specific diagnostic trouble codes (DTCs) in the engine control module (ECM).

This TSB provides a straightforward diagnostic and repair procedure, emphasizing that in most cases, the solution for an Audi fuel cap leaking DTC P044200 or related codes does not require replacing components or conducting a smoke test.

Symptoms

Owners of affected Audi vehicles may notice the following symptom:

• The "MIL/exhaust emission warning light is on" in the instrument cluster. This light indicates a potential problem with the vehicle's emissions system, which includes components like the fuel tank and its sealing.

Fault Codes / DTCs

When the fuel tank detection system identifies a leak, the dealer's diagnostic tools may find one or more of the following Diagnostic Trouble Codes (DTCs) stored in the engine control module (ECM - J623, address word 0001):

• DTC P045600: "EVAP Emission Control System (very small leak) leak detected"
• DTC P00EF00
• DTC P044200

These codes specifically point to issues within the Evaporative Emission Control System (EVAP), which is designed to prevent fuel vapors from escaping into the atmosphere.

Important Warnings for Owners

Audi TSB 2078916/1 contains a crucial piece of information for both technicians and owners regarding the repair process:

• "Replacing components or a smoke test is not required."

This means that if your vehicle is diagnosed with one of the listed DTCs due to a fuel tank cap seal issue, you should not be charged for a new fuel cap or an expensive smoke test. The primary solution involves a simple inspection and correction of the existing seal.

Diagnosis and Repair Procedure Summary

The repair for an Audi fuel cap leaking DTC P044200 or related codes is relatively simple and focuses on the fuel tank cap seal. Technicians are instructed to:

1. Inspect the fuel tank cap: Carefully check the fuel tank cap for any signs of a twisted seal.
2. Correct a twisted seal: If the seal is found to be twisted, as depicted in the TSB's accompanying image, it should be correctly fitted back into its proper position.

This procedure aims to resolve the leak by ensuring the seal provides an airtight closure, thereby clearing the diagnostic trouble codes and turning off the MIL/exhaust emission warning light. The TSB explicitly states that replacing components or performing a smoke test is not necessary for this specific condition.

Warranty Information

For vehicles still under warranty, claims for this repair should be submitted in accordance with the Audi Warranty Policies and Procedures Manual. The TSB specifies the following labor operations:

• Modify Seal Cap: Labor operation 2005 4999, allotted 10 Time Units (TU).
• GFF: Labor operation 0150 0060, with time stated on the diagnostic protocol.
• GFF: Labor operation 0150 0010, referring to the Service Repair Time (SRT) with associated operations.

If the vehicle is outside of its warranty period, this Technical Service Bulletin is for informational purposes only.