2023-2024 Audi e-tron Air Suspension Fault C118D01

Owners of certain 2023-2024 Audi models, including the Audi e-tron, may encounter an "Air suspension: system fault" message displayed in the instrument cluster. This issue is addressed by Audi Technical Service Bulletin (TSB) 2073034/1, released on February 19, 2024. The TSB provides diagnostic and repair procedures for this specific air suspension system fault.

The TSB applies to vehicles equipped with air suspension and specifically targets issues related to the compressor electronics control unit J1135. An improved software solution for the compressor electronics J1135 is currently planned, indicating ongoing efforts to resolve this condition.

Symptoms

If your vehicle is affected by this issue, the primary symptom you will notice is a warning message appearing in your instrument cluster. The message displayed is:

• "Air suspension: system fault"

This message indicates a problem with the vehicle's air suspension system, which can impact ride height and comfort.

Fault Codes / DTCs

When diagnosing the "Air suspension: system fault" message, technicians will typically find a specific Diagnostic Trouble Code (DTC) logged in the suspension control unit J775 (diagnostic address 0074). The relevant DTC for this issue is:

• C118D01: Compressor for level control electrical error

This code points directly to an electrical malfunction within the compressor system responsible for maintaining the vehicle's air suspension level.

Diagnosis

For a proper diagnosis, a technician will first verify the presence of the DTC C118D01. The TSB 2073034/1 specifies that the described procedure only applies if the compressor electronics with part number index A (specifically, part number 4M0.907.778.A) are fitted in the vehicle.

If no irregularities are found during the inspection of the wiring and contacts at both the air compressor and the compressor electronics control unit J1135, the next steps depend on the DTC's status.

Important Warnings

It is crucial to correctly identify the faulty component. The TSB explicitly states that if the DTC C118D01 is active/static and persists after cycling the ignition, the control unit for compressor electronics J1135 should be replaced. Technicians are advised not to replace the air compressor itself, as this will not resolve the underlying electrical error.

Repair Procedure Summary

The repair procedure outlined in TSB 2073034/1 depends on the status of the C118D01 DTC:

1. If the DTC is passive/intermittent: The technician should simply delete the DTC from the system. This suggests a temporary fault that does not require component replacement.
2. If the DTC is active/static: If the C118D01 code remains active and static even after turning the ignition off and on again, the control unit for compressor electronics J1135 must be replaced. This is a critical step to address the persistent electrical error. The TSB emphasizes replacing the J1135 control unit and not the entire air compressor.

Required Parts and Tools

For the repair involving the replacement of the compressor electronics control unit J1135, the following parts may be required:

• Control unit for compressor electronics J1135: Quantity 01 (if necessary)
• Fasteners, Bolts, Nuts, and Screws: As needed per the Repair Manual

Technicians should consult ETKA (Electronic Parts Catalog) for the latest information and specific part numbers. The affected compressor electronics unit has a part number index A, such as 4M0.907.778.A.

Warranty Information

This repair, as detailed in TSB 2073034/1, is typically covered under Audi's warranty. The claim types include:

• 110: For vehicles up to 48 months or 50,000 miles.
• G10: For CPO (Certified Pre-Owned) covered vehicles, requiring owner verification.

If the vehicle is outside of any warranty, this Technical Service Bulletin serves as informational guidance only. The Service Number for this operation is 4316, and the Damage Code is 0039. Specific labor operations and times are provided for checking wiring (4316 0199, 30 TU) and removing/installing the control unit J1135 (4316 19xx). All warranty claims must adhere to the Audi Warranty Policies and Procedures Manual.

Owner Action

If your 2023-2024 Audi e-tron is displaying the "Air suspension: system fault" message or you suspect an issue with your air suspension, it is recommended to schedule an appointment with an authorized Audi service center. Provide them with the symptom and mention the potential relevance of TSB 2073034/1 and DTC C118D01. The technicians will perform the necessary diagnostics to confirm the issue and apply the appropriate repair, which for an active/static Audi e-tron air suspension fault, involves replacing the compressor electronics control unit J1135.

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Source: NHTSA ID: 10250549