2023-2026 Audi Air Suspension Fault C118D01

Symptoms

Owners of affected 2023-2026 Audi vehicles may notice specific warnings related to their air suspension system. The primary symptom is the illumination of the air spring symbol on the instrument cluster.

Additionally, a message stating "Air suspension: system fault" will be displayed in the instrument cluster. These indicators point to a potential issue with the vehicle's level control system.

Fault Codes / DTCs

When diagnosing the air suspension issue, technicians will typically find a specific Diagnostic Trouble Code (DTC) stored in the suspension control unit -J775-. This code precisely identifies the nature of the electrical problem.

Code	Description	Module
C118D01	Compressor for level control electrical error	Suspension control unit -J775- (diagnostic address 0074)

This DTC C118D01 confirms an electrical fault within the air suspension compressor's control system.

Diagnosis / Trigger Conditions

The presence of DTC C118D01 in the suspension control unit -J775- is the key diagnostic indicator for this issue. Before proceeding with repairs, technicians are advised to try and reproduce the customer complaint to clearly assign it to this TSB.

Initial diagnostic steps involve checking the wiring and contacts connected to both the air compressor and the compressor electronics control unit J1135. If no irregularities are found with these connections, the repair procedure can then be initiated.

Repair Procedure Summary

The repair for the Audi air suspension fault C118D01 focuses on replacing a specific component. After confirming no wiring or contact issues, the primary step is to replace the control unit for compressor electronics J1135.

It is crucial to note that only the control unit J1135 should be replaced, not the entire air compressor itself. Figure 1 in the technical bulletin illustrates the compressor electronics control unit J1135, typically identified as component number 30 in the diagram.

Required Parts and Tools

To perform this repair, specific parts are required. The main component is the control unit for compressor electronics J1135. Fasteners, bolts, nuts, and screws may also be needed.

Specific part numbers for the control unit and fasteners are available through ETKA (Electronic Parts Catalog) and ELSA (Electronic Service Information System). Technicians should consult these systems for the most current and superseding part numbers.

Owner Action

If your 2023-2026 Audi displays the air spring symbol or the "Air suspension: system fault" message, and you suspect an Audi air suspension fault C118D01, it is recommended to schedule an appointment with an authorized Audi service center. Provide them with details of the symptoms you are experiencing.

Warranty coverage for this repair depends on your vehicle's warranty status. If your vehicle is outside of warranty, this Technical Service Bulletin serves as informational guidance, and repair costs may apply. Audi warranty claims are subject to review and audit according to Audi Warranty Policies and Procedures.

---

Source: NHTSA ID: 11027353