2021 Audi Q7/Q8 MIL On with DTC P148D00 and P044200

Symptoms

Owners of affected 2021 Audi Q7, Q8, SQ7, SQ8, and RS Q8 vehicles may notice the Malfunction Indicator Lamp (MIL) illuminated on their dashboard. This indicates a potential issue with the vehicle's emission system.

Fault Codes / DTCs

When the MIL is on, a diagnostic scan may reveal specific Diagnostic Trouble Codes (DTCs) stored in the Engine Control Module (ECM J623, address word 0001). These codes point to an evaporative emission system concern.

The following DTCs are associated with this issue:

Code	Description
P148D00	"Evaporative Emission System Leak Detection Pump implausible frequency"
P044200	"EVAP Emission Control System (Small Leak) Leak Detected"

No other relevant DTCs should be present for this specific condition. If other codes are logged, they may indicate a different problem.

Technical Background

Audi has identified a software issue within the Engine Control Module (ECM J623) that can lead to the false detection of an evaporative emission system leak. Specifically, the DTC P044200, or "Small leak detected," may be stored even when there are no actual leaks in the fuel tank system.

This software anomaly causes the vehicle's diagnostic system to misinterpret normal operating conditions, triggering the Malfunction Indicator Lamp. This TSB, 2073032/2, provides a solution to correct this software error.

Repair Procedure Summary

Addressing the Audi Q7/Q8 MIL P148D00 P044200 issue involves a software update to the ECM. Technicians must follow specific instructions to ensure the update is performed correctly.

1. Consult SVM Operating Instructions: The first step requires adherence to all instructions outlined in TSB 2011732, which covers Software Version Management (SVM) operating procedures. This ensures proper preparation for the software update.
2. ECM Software Update: The ECM (J623) needs to be updated using the SVM action code 01A255. This update will install the revised software version that resolves the false leak detection issue. It is crucial to always use DoIP (Diagnostic over Internet Protocol) when flashing a control module via ODIS in supported vehicles. DoIP can be activated by selecting Administration >> General >> GFF Process >> DoIP communication >> Only allow DoIP communication. This setting automatically resets after the diagnostic session.
3. Leak System Verification: After the software update, technicians must verify that there are no actual leaks present in the fuel system. This step confirms that the software fix has resolved the false positive and that no underlying hardware issue exists.

Required Software and Part Numbers

The software update involves specific new software versions for the ECM, depending on the vehicle model. The SVM action code required for this update is 01A255.

Model	Diagnostic Address	Old Software Part Number	Old Software Version	New Software Part Number	New Software Version
Q7	0001	4M0907559D	<0003	4M0907559D	0004
Q7	0001	4M0907559L	<0002	4M0907559L	0003
Q8	0001	4M8907557F	<0001	4M8907557F	0002
Q8	0001	4M8907559M	<0002	4M8907559M	0003

Warranty Information

This repair, identified by Service Number 2048 and Damage Code 0040, is covered under Audi's warranty program. The claim type is applicable for vehicles up to 48 months or 50,000 miles.

For Certified Pre-Owned (CPO) vehicles, a G10 claim type is used, requiring verification of owner eligibility. Labor operations include a maximum of 80 time units (TU) for the software update and checking for DTCs, and 10 TU for charging the battery (operation code 2706 8950). Diagnostic time and road tests are not billable under this specific claim.

Important Warnings

If your vehicle is outside of any applicable warranty period, this Technical Service Bulletin is for informational purposes only. In such cases, any diagnostic or repair costs would typically be the owner's responsibility.

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Source: NHTSA ID: 11002119