2021-2024 Audi A4/A5 P04F000 Purge Line Performance TSB

Symptoms

When driving your 2021-2024 Audi A4 or A5, you might notice the Malfunction Indicator Lamp (MIL), commonly known as the check engine light, illuminating on your dashboard. This warning light indicates that the vehicle's engine control module (ECM) has detected a potential issue within the emissions system. This specific symptom is directly linked to the "EVAP system high pressure purge line performance" issue.

Fault Codes / DTCs

The primary diagnostic trouble code (DTC) associated with this condition is P04F000. This code specifically points to an "EVAP system high pressure purge line performance" fault. The code is stored within the Engine Control Module (ECM), identified as -J623- (address word 0001), indicating a problem with the evaporative emissions system's ability to properly purge fuel vapors.

Diagnosis / Trigger Conditions

Audi Technical Service Bulletin 2069834/3 outlines the diagnostic steps technicians should follow. The process begins by verifying the customer's reported condition, specifically the illuminated MIL. Technicians are instructed to perform a comprehensive EVAP leak test, adhering to procedures detailed in the Electronic Service Information System (ELSA). A critical step involves visually inspecting and confirming that both ends of the vent pipe, which runs from the turbocharger to the engine's breather, are securely connected. If the vehicle is still covered under the New Vehicle Limited Warranty, technicians must contact an Audi Technical Assistance Center (TAC) consultant before proceeding with any repairs. This contact requires attaching the diagnostic log, EVAP leak test results, and photographs of any identified leak sources to a TAC Web Ticket. This detailed diagnostic approach helps pinpoint the exact cause of the "EVAP system high pressure purge line performance" issue.

Important Warnings

Owners and technicians should be aware of several key points from Audi TSB 2069834/3. Audi states that "No changes to production have been made, as no issue has been identified" regarding the underlying cause of the P04F000 code. Furthermore, this TSB is explicitly "informational only and not applicable to any Audi Warranty." This means that diagnostic time or any potential repairs might not be covered under standard warranty terms if your vehicle is outside the New Vehicle Limited Warranty period. Crucially, the TSB advises against replacing parts without first consulting the Audi Technical Assistance Center (TAC), as the primary goal is to gather data rather than immediately replace components.

Repair Procedure Summary

The Audi Technical Service Bulletin 2069834/3 does not prescribe a direct repair action in terms of part replacement. Instead, it focuses on a thorough diagnostic and information-gathering process. Technicians are guided to verify the customer's complaint of an illuminated Malfunction Indicator Lamp (MIL) and the presence of the P04F000 diagnostic trouble code. The procedure includes performing an EVAP system leak test according to the Electronic Service Information System (ELSA) guidelines and meticulously checking the connections of the vent pipe from the turbocharger to the breather. For vehicles under the New Vehicle Limited Warranty, the TSB mandates contacting the Audi Technical Assistance Center (TAC) with detailed diagnostic logs, leak test results, and photographic evidence of any leaks found. This approach aims to collect data on the "EVAP system high pressure purge line performance" issue to aid in future understanding and potential solutions.

Owner Action

If you own a 2021-2024 Audi A4 or A5 and experience an illuminated check engine light along with the P04F000 diagnostic trouble code, it is recommended to schedule a service appointment with an authorized Audi dealership. Inform the service advisor about Audi Technical Service Bulletin 2069834/3, as it provides specific guidance for diagnosing this particular "EVAP system high pressure purge line performance" issue. Be prepared that this TSB is primarily for diagnostic information gathering, and any repair costs may not be covered by warranty if your vehicle is outside the New Vehicle Limited Warranty period. Early diagnosis can help prevent further complications related to your vehicle's evaporative emissions system.

Source: NHTSA ID 10249213