2021-2023 Audi A5 P04F000 EVAP System Purge Line TSB

Symptoms of the P04F000 EVAP System Issue

Owners of affected 2021-2023 Audi A4, A5, and Q5 models may notice that the Malfunction Indicator Lamp (MIL) is illuminated on their dashboard. This is the primary symptom reported by customers related to this condition.

Diagnostic Trouble Code (DTC) P04F000

When the MIL is illuminated, a diagnostic scan of the vehicle's engine control module (ECM), specifically the -J623- unit (address word 0001), may reveal the following Diagnostic Trouble Code:

This P04F000 code points to an issue with the evaporative emission control system's purge line, which manages fuel vapor pressure.

Technical Background and Audi's Investigation

Audi has noted that various parts have been replaced under warranty for the condition indicated by the P04F000 code, but no underlying issues with these replaced parts were identified. This suggests the problem may not be with the components themselves, but rather with how the system operates or is diagnosed.

Technical Service Bulletin 20 23 62 2069834/2, which supersedes previous bulletin Group 20 #23-55 dated March 27, 2023, highlights that Audi of America is actively seeking technical information regarding this condition. The manufacturer has not identified an inherent production issue and has made no changes to the production process related to this specific concern. This TSB is primarily an information-gathering effort to assist Audi in diagnosing potential issues.

Initial Diagnostic Steps for Technicians

Before any parts are replaced, technicians are instructed to perform specific diagnostic steps. These include verifying the condition, conducting an EVAP leak test using the ELSA diagnostic system, and confirming that both ends of the vent pipe, from the turbocharger to the breather, are properly connected. These steps are crucial for accurately diagnosing the source of the P04F000 EVAP system high pressure purge line performance issue.

Important Warnings and Information for Owners

If your vehicle is still within its New Vehicle Limited Warranty, your technician must contact an Audi Technical Assistance Center (TAC) consultant before proceeding with any repairs. The diagnostic log and EVAP leak test results must be attached to the TAC Web Ticket. If a leak is identified, photographs of the leak source should also be provided to the TAC contact. It is important to note that this TSB (2069834) is informational only and does not apply to any Audi Warranty claims for repair costs. This means the TSB itself does not authorize warranty coverage for the diagnostic or repair work.

What Audi Owners Should Do

If your 2021-2023 Audi A5, A4, or Q5 is displaying an illuminated MIL and you suspect a P04F000 EVAP system high pressure purge line performance issue, you should schedule an appointment with an authorized Audi service center. Inform them about the illuminated MIL and mention Technical Service Bulletin 20 23 62 2069834/2. Be aware that the dealership will need to follow Audi's specific diagnostic and information-gathering procedures, which include contacting the Technical Assistance Center if your vehicle is under warranty.

Source: NHTSA ID: 10245614