2023-2025 Audi Air Suspension Fault C118D01 TSB

Symptoms of an Audi Air Suspension Fault C118D01

Owners of 2023-2025 Audi vehicles may experience several symptoms related to an air suspension system malfunction. The most direct indication is a warning message displayed in the instrument cluster.

Common symptoms include:

• The message "Air suspension: system fault" appearing on the instrument cluster.
• A "shock absorber control system malfunction display" indicating issues with the damping system.
• Problems with automatic damper adjustment, potentially leading to incorrect operation or no function.
• The level control system, responsible for pitch and roll compensation, may exhibit no function.
• The driving dynamics performance indicator display may not activate or show malfunctions.

These issues collectively point to a problem within the vehicle's chassis damping and suspension regulation systems, often triggered by an Audi air suspension fault C118D01.

Fault Codes (DTCs)

When an Audi air suspension fault C118D01 occurs, technicians will find a specific Diagnostic Trouble Code (DTC) logged in the vehicle's suspension control unit. This code helps pinpoint the exact nature of the electrical malfunction.

Code	Description	Module	Storage State
C118D01	Compressor for level control system Electrical malfunction	Suspension control unit -J775- (diagnostic address 0074)	Static / Intermittent

The presence of DTC C118D01 confirms an electrical issue with the compressor responsible for the level control system.

Diagnosis and Trigger Conditions

To diagnose the Audi air suspension fault C118D01, technicians will first attempt to reproduce the customer complaint. This involves verifying the "Air suspension: system fault" message and confirming the presence of DTC C118D01.

The diagnostic process includes checking the wiring and electrical contacts at both the air compressor and the compressor electronics control unit -J1135-. If these components show no irregularities, the repair procedure can proceed.

Important Warnings for Owners and Technicians

Audi has issued specific guidelines regarding this technical service bulletin (TSB 2073034/7) to ensure correct repairs and warranty claims. This TSB has undergone several revisions, with Revision 7 being the latest, indicating ongoing refinement of the repair process.

• Repair Criteria: "The following repair must only be carried out if all the criteria (model/type, chassis number, engine/motor and gearbox code, PR number(s), part number, software version, code etc.) apply exactly. Otherwise, this solution will not eliminate the problem and repeat repairs may be necessary. In such a case, we may reject the warranty claim and charge back the cost of the parts."
• Part Replacement: Technicians are explicitly instructed to "Replace the control unit for compressor electronics -J1135- (not the air compressor)." This prevents unnecessary replacement of the entire air compressor unit.
• Warranty Coverage: If your vehicle is outside of any applicable warranty, this Technical Service Bulletin serves as informational guidance only, and repair costs may not be covered.

Repair Procedure Summary

The resolution for the Audi air suspension fault C118D01 involves a targeted replacement of a specific component. After confirming the DTC and performing initial wiring checks, the main step is to replace the compressor electronics control unit -J1135-.

The general procedure is as follows:

1. Confirm the customer complaint and verify the presence of DTC C118D01.
2. Inspect the wiring and electrical contacts connected to the air compressor and the compressor electronics -J1135-.
3. If no irregularities are found with the wiring or contacts, proceed to replace the control unit for compressor electronics -J1135-.
4. Perform necessary labor operations, including removal and installation of the control unit, and conduct a road test to ensure the fault is resolved.

This procedure focuses on the electronics unit rather than the entire compressor, addressing the electrical malfunction directly.

Required Parts

For the repair of the Audi air suspension fault C118D01, specific parts are required. It is crucial to use only the parts listed in this TSB, as they may differ from those found in other catalogs like ETKA.

• Control unit for compressor electronics -J1135-: Part Number 4M0.907.778 (Quantity: 1)
• Fasteners, Bolts, Nuts, and Screws: As needed per the repair manual (refer to ETKA/ELSA for specific details).

Owner Action

If you are experiencing an "Air suspension: system fault" message or suspect an Audi air suspension fault C118D01 in your 2023-2025 Audi, it is recommended to schedule an appointment with an authorized Audi service center. Provide them with details of the symptoms you are observing.

While the TSB outlines a specific repair, the applicability of warranty coverage will depend on your vehicle's warranty status. The service center can confirm if your vehicle meets the criteria for this bulletin and advise on potential costs.

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NHTSA ID: 11015758