2023-2025 Audi Air Suspension Fault C118D01 TSB

Symptoms of an Air Suspension Malfunction

Owners of affected 2023-2025 Audi vehicles may notice a specific warning message appearing in the instrument cluster. The primary indicator of this issue is the message "Air suspension: system fault". This warning suggests a problem with the vehicle's air suspension system, which can impact ride comfort and vehicle leveling.

Additional symptoms reported include issues with the shock absorber control system, automatic damper adjustment, and the level control system. These problems can manifest as incorrect operation sequences or a complete loss of function in these systems. The driving dynamics performance indicator display may also fail to activate.

Fault Codes / DTCs

When diagnosing this problem, technicians will typically find a specific Diagnostic Trouble Code (DTC) stored in the suspension control unit (J775).

Code	Description	Fault Symptom	Storage State
C118D01	Compressor for level control system Electrical malfunction	information, navigation, communication, entertainment -> malfunction; display symbols -> shock absorber control system malfunction display; chassis -> damping/suspension regulation -> automatic damper adjustment; chassis -> damping/suspension regulation -> damper adjustment; chassis -> level control system, pitch and roll compensation; chassis -> damping/suspension regulation -> automatic level control system; chassis -> damping/suspension regulation -> level control system; information, navigation, communication, entertainment -> indicator display symbols -> driving dynamics performance indicator display	Static, Intermittent

This DTC C118D01 points directly to an electrical issue within the compressor for the level control system.

Diagnosis and Trigger Conditions

To accurately diagnose the Audi e-tron air suspension fault, technicians should first confirm the customer complaint and verify the presence of the "Air suspension: system fault" message. The key diagnostic step involves checking for the C118D01 DTC logged in the J775 suspension control unit.

The bulletin emphasizes the importance of reproducing the customer complaint to ensure the TSB is applicable. It also states that the repair should only be carried out if all criteria, including model/type, chassis number, engine/motor and gearbox code, PR number(s), part number, and software version, are met. Failing to do so may result in the problem persisting and potential warranty claim rejections.

Repair Procedure Summary

The repair for the Audi e-tron air suspension fault primarily involves addressing the compressor electronics control unit, J1135. The procedure is as follows:

1. Initial Inspection: Technicians should thoroughly check the wiring and electrical contacts at both the air compressor and the J1135 compressor electronics control unit. This step ensures that the issue isn't simply a loose connection or damaged wire.
2. Control Unit Replacement: If no irregularities are found with the wiring or contacts, the next step is to replace the compressor electronics control unit, J1135. It is crucial to note that only the control unit should be replaced, not the entire air compressor assembly.
3. Post-Repair Testing: After the replacement, a road test is recommended to confirm that the "Air suspension: system fault" message no longer appears and that the air suspension system functions correctly. Diagnostic protocols may also include GFF (Guided Fault Finding) procedures.

Required Parts and Tools

The primary part required for this repair is the control unit for compressor electronics J1135.

• Part Number: 4M0.907.778 (Control unit for compressor electronics J1135)
• Additional Parts: Fasteners, bolts, nuts, and screws as needed, which can be referenced in ETKA/ELSA.

Important Warnings

Owners and technicians should be aware of a critical instruction from Audi regarding this repair:

• "Replace the control unit for compressor electronics -J1135- (not the air compressor)." This explicitly states that the air compressor itself should not be replaced as part of this specific repair, preventing unnecessary costs and labor.

Warranty Information

For vehicles still under warranty, this repair may be covered. The bulletin specifies the following codes for warranty claims:

• Service Number: 4316
• Damage Code: 0039

However, if the vehicle is outside of its warranty period, this Technical Service Bulletin is for informational purposes only, and the owner would be responsible for the repair costs. All warranty claims must adhere to the Audi Warranty Policies and Procedures Manual.

Revision History

This Technical Service Bulletin (2073034/8) has undergone several revisions to refine the repair process and warranty information:

• Revision 8: Modified Labor Operations related to warranty.
• Revision 7 (February 21, 2025): Further revised Warranty (Modified Labor Operations) and added a note to the service procedure.
• Revision 6 (June 28, 2024): Updated the service procedure.

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Source: NHTSA ID: 11016527