2023-2024 Audi Air Suspension Fault C118D01

Symptoms

Owners of certain 2023-2024 Audi models may observe a specific warning message in their instrument cluster. The verbatim message reported is: "Air suspension: system fault". This indicates a potential issue with the vehicle's air suspension system.

Fault Codes / DTCs

When the "Air suspension: system fault" message appears, workshops typically find a specific Diagnostic Trouble Code (DTC) logged in the suspension control unit -J775- (diagnostic address 0074). The relevant fault code is:

Code	Description	Module
C118D01	Compressor for level control electrical error	Suspension Control Unit -J775-

This DTC points to an electrical problem with the compressor responsible for the vehicle's level control system. This is the core of the Audi air suspension fault C118D01.

Important Notices

Audi has issued a specific notice regarding the repair procedure for the Audi air suspension fault C118D01:

• Replacement of J1135: If the Diagnostic Trouble Code (DTC) C118D01 is stored for a second time in the J775 control unit as passive/intermittent, the compressor electronics control unit J1135 must be replaced. This is crucial for resolving the recurring issue.

Diagnosis

If an Audi vehicle presents with the "Air suspension: system fault" message and DTC C118D01, technicians should first inspect the wiring and contacts at both the air compressor and the compressor electronics control unit J1135.

• If the DTC C118D01 is found to be passive/intermittent and no wiring issues are present, the DTC should be deleted.
• If the DTC C118D01 is active/static and persists after cycling the ignition, the control unit for compressor electronics J1135 should be replaced. It is important to note that the air compressor itself should not be replaced in this scenario, only the J1135 control unit.

Repair Procedure Summary

The primary solution for the Audi air suspension fault C118D01, as outlined in Technical Service Bulletin 43 24 87 2073034/3, involves addressing the compressor electronics J1135. An improved software solution for the compressor electronics J1135 is planned.

For vehicles already experiencing the fault, the procedure specifically applies if compressor electronics with part number index A (part number 4M0.907.778.A) are installed. The repair involves removing and installing the control unit J1135. This process is detailed in the workshop manual and includes specific labor operations (4316 19xx) for warranty claims.

Required Tools or Parts

To perform the repair for the Audi air suspension fault C118D01, technicians will need:

• Control unit for compressor electronics J1135: This part may be necessary for replacement, with a quantity of 01.
• Fasteners, Bolts, Nuts, and Screws: As needed, according to the Repair Manual.
• ETKA/ELSA: These systems are used to find the latest information on parts and bulletins.

Warranty Information

This Technical Service Bulletin (TSB 2073034/3) outlines warranty coverage for the repair of the Audi air suspension fault C118D01. Claims can be submitted under:

• Claim Type 110: For vehicles up to 48 months or 50,000 miles.
• Claim Type G10: For Certified Pre-Owned (CPO) vehicles, provided the owner is verified.

If the vehicle is outside of any applicable warranty, this bulletin serves as informational guidance only. The service number for this issue is 4316, with a damage code of 0039. Diagnostic time is capped at 50 Technical Units (TU). All warranty claims must adhere to the Audi Warranty Policies and Procedures Manual.

Owner Action

If you own a 2023-2024 Audi and experience the "Air suspension: system fault" message or suspect an Audi air suspension fault C118D01, it is recommended to schedule an appointment with an authorized Audi service center. They can diagnose the issue using specialized tools and determine if the compressor electronics control unit J1135 needs replacement according to TSB 43 24 87 2073034/3.

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Source: NHTSA ID: 10253745