2022-2026 Audi e-tron GT Refrigerant Pressure Sensor DTCs

Audi has issued Technical Service Bulletin (TSB) 2078654/1 to address instances where specific diagnostic trouble codes (DTCs) related to refrigerant pressure sensors PT1, PT2, and PT3 are stored in the thermal management control unit (diagnostic address 00C5) of 2022-2026 Audi e-tron GT vehicles. This TSB clarifies that these fault entries may occur without any actual functional problems with the vehicle's air conditioning system, indicating a potential false positive for an "Audi e-tron GT refrigerant pressure sensor fault."

This bulletin is particularly relevant for owners who might see these codes during a workshop visit but experience no noticeable issues with their climate control. The TSB provides guidance for technicians on how to correctly diagnose and manage these event memory entries.

Symptoms

Owners of affected Audi e-tron GT models may not experience any direct symptoms of an air conditioning malfunction. The issue is identified when a diagnostic scan reveals specific event memory entries for refrigerant pressure sensors PT1, PT2, or PT3 in the thermal management control unit (diagnostic address 00C5). These entries are typically described as an "implausible signal," meaning the control unit receives data that falls outside its expected parameters, triggering a fault code despite the system operating normally. This can lead to a perceived "Audi e-tron GT refrigerant pressure sensor fault" without a real underlying problem.

Fault Codes / DTCs

The following diagnostic trouble codes (DTCs) may be found in the thermal management control unit (diagnostic address 00C5):

Code	Description	Sensor	Symptom (HEX/DEC)
P053100	A/C Pressure/Temperature Sensor 1, implausible signal	PT1	0x00D6D8 (55000)
P0EBF00	A/C Pressure/Temperature Sensor 1, implausible signal	PT1	0x00D6DE (55006)
P0EBF00	A/C Pressure/Temperature Sensor 1, implausible signal	PT1	0x00D6ED (55021)
P251600	A/C Pressure/Temperature Sensor 2, implausible signal	PT2	0x00D6D9 (55001)
P0EC400	A/C Pressure/Temperature Sensor 2, implausible signal	PT2	0x00D6DF (55007)
P0EC400	A/C Pressure/Temperature Sensor 2, implausible signal	PT2	0x00D6EE (55022)
P1C5E00	A/C Pressure/Temperature Sensor 3, implausible signal	PT3	0x00D6DA (55002)
P1C5E00	A/C Pressure/Temperature Sensor 3, implausible signal	PT3	0x00D6E0 (55008)
P1C5E00	A/C Pressure/Temperature Sensor 3, implausible signal	PT3	0x00D6EF (55023)

Technical Background

Audi has identified that the root cause of these implausible signal DTCs is a software issue. This software anomaly can lead to the thermal management control unit misinterpreting data from the refrigerant pressure sensors, causing it to log a fault code even when the sensors and the air conditioning system are functioning correctly. This means the "Audi e-tron GT refrigerant pressure sensor fault" is often a diagnostic error rather than a hardware failure.

Important Warnings for Owners

Audi provides specific instructions for technicians regarding these event memory entries:

• "Pay attention to the specific symptoms for each event memory entry!"
• "If the index is J, the event memory entries can be ignored and deleted."
• "However, if the same event memory entry as described above in “Workshop findings” is logged in the vehicle but with a different symptom and there is also an issue with air conditioning system, the entries cannot be ignored!"
• "On Audi e-tron GT vehicles from model year 2025 or later with PR number GP1, the event memory entries listed above for refrigerant pressure sensor PT3 can occur for all indices, not just index J. The entries can be ignored for all indices if the symptoms match those in the above list and there are no issues with the air conditioning system."

Repair Procedure Summary

When a technician encounters these DTCs in an affected Audi e-tron GT, the procedure outlined in TSB 2078654/1 involves several key steps:

1. Diagnosis Confirmation: The technician will first confirm the presence of the specified event memory entries in the thermal management control unit (00C5).
2. System Functionality Check: Crucially, they will verify that there are no actual performance or functional issues with the vehicle's air conditioning system.
3. Part Index Verification: The part index of the installed refrigerant pressure sensors must be checked. Specifically, if refrigerant pressure sensors with part number 4M0959603J are installed, and no actual A/C issues are present, the event memory entries may be logged without good reason.
4. DTC Management: If the conditions are met (i.e., no actual A/C system issues and the specific sensor part number or model year/PR number criteria for PT3 are met), the event memory entries can be ignored and deleted from the system. This effectively resolves the false "Audi e-tron GT refrigerant pressure sensor fault."
5. Further Action: If, however, there are genuine symptoms of an air conditioning system malfunction, or if the part index of the sensors does not match the specified conditions, further diagnostic steps and potential repairs will be necessary.

Warranty Information

For vehicles still under warranty, this Technical Service Bulletin provides guidance for claim submission. The Service Number associated with this TSB is 8711, and the Damage Code is 0040. Labor operations include GFF / Guided Functions 0150 0010 (See SRT with associated operations) and 0150 0060 (Labor according to the diagnostic log). All warranty claims must adhere to the Audi Warranty Policies and Procedures Manual and are subject to review or audit by Audi Warranty. If the vehicle is outside of any warranty, this TSB serves as informational guidance.

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Source: NHTSA ID: 11021476