2023-2024 Audi Air Suspension System Fault TSB C118D01

Symptoms

Owners of affected 2023-2024 Audi vehicles may observe the message "Air suspension: system fault" displayed in the instrument cluster. This warning indicates a problem with the vehicle's air suspension system.

Fault Codes / DTCs

When diagnosing the Audi air suspension C118D01 issue, workshops will find the following Diagnostic Trouble Code (DTC) logged in the suspension control unit J775 (diagnostic address 0074):

Code	Description
C118D01	Compressor for level control electrical error

Diagnosis / Trigger Conditions

The DTC C118D01 is logged when there is an electrical error with the compressor for level control. Technicians will first check the wiring and contacts at the air compressor and compressor electronics J1135. The TSB also notes that improved software for compressor electronics J1135 is planned as a production solution.

Important Warnings

If the DTC C118D01 is found to be active/static and remains active after cycling the ignition off and on again, the procedure specifies to replace the control unit for compressor electronics J1135. It is crucial to note that technicians are instructed not to replace the air compressor itself, as this will not resolve the underlying electrical error.

Repair Procedure Summary

For the Audi air suspension C118D01 fault, the repair process depends on the nature of the DTC:

1. Initial Check: Technicians will inspect the wiring and contacts connected to the air compressor and the compressor electronics J1135.
2. Passive/Intermittent DTC: If the DTC C118D01 is logged as passive or intermittent, it should be deleted.
3. Active/Static DTC: If the DTC C118D01 is active or static and persists even after the ignition has been turned off and on, the control unit for compressor electronics J1135 must be replaced. This procedure applies specifically if the compressor electronics with part number 4M0.907.778.A are fitted in the vehicle.

Required Parts

To perform the repair, the following parts may be required:

• Control unit for compressor electronics J1135: Quantity 01 (if necessary, reference ETKA for specific part number).
• Fasteners, Bolts, Nuts, and Screws: As needed per the repair manual (reference ETKA/ELSA).

Warranty Information

This repair is covered under Audi's warranty for up to 48 months or 50,000 miles. For Audi Certified Pre-Owned (CPO) vehicles, coverage falls under the G10 warranty, requiring owner verification. If the vehicle is outside of any applicable warranty, this Technical Service Bulletin (TSB) serves as informational guidance only.

TSB Revision History

This Technical Service Bulletin, identified as 43 24 83 2073034/2, was issued on March 13, 2024, and supersedes a previous bulletin, Group 43 number 24-82, dated February 19, 2024. The revision history is as follows:

• Revision 2 (March 13, 2024): Revised Warranty (Modified Labor Operations).
• Revision 1 (February 19, 2024): Initial publication.

Owner Action

If your 2023-2024 Audi displays the "Air suspension: system fault" message or you suspect an Audi air suspension C118D01 issue, it is recommended to schedule an appointment with an authorized Audi service center. Provide them with the symptom description and mention this Technical Service Bulletin (TSB 43 24 83 2073034/2) for efficient diagnosis and repair.

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Source: NHTSA ID: 10251999