2023-2025 Audi Air Suspension Fault DTC C118D01

Audi has released Technical Service Bulletin (TSB) 2073034/7 to address instances where the 'Air suspension: system fault' message appears in the instrument cluster, often accompanied by diagnostic trouble code (DTC) C118D01. This TSB specifically targets an electrical malfunction within the compressor for the vehicle's level control system, which can lead to an Audi e-tron air suspension fault.

This bulletin applies to various 2023-2025 Audi models, including the Q5, Q5 e, SQ5, Q7, SQ7, Q8, SQ8, RS Q8, A6, A6 allroad, S6, RS 6 Avant, A7, S7, RS 7, S8, and e-tron models. The information helps technicians accurately diagnose and resolve the underlying issue causing the air suspension system fault.

Symptoms

Owners of affected Audi vehicles may observe the following symptoms related to an Audi e-tron air suspension fault:

• The message "Air suspension: system fault" displayed in the instrument cluster.
• Malfunction display symbols for the shock absorber control system activating or failing to activate.
• Issues with damping/suspension regulation, including incorrect operation sequences or a complete loss of function for damper adjustment.
• Problems with the level control system, pitch, and roll compensation functionality.
• The driving dynamics performance indicator display may not activate.

Fault Codes / DTCs

When an Audi e-tron air suspension fault occurs, the suspension control unit -J775- (diagnostic address 0074) will typically log the following diagnostic trouble code:

Code	Description	Storage State
C118D01	Compressor for level control system Electrical malfunction	static
C118D01	Compressor for level control system Electrical malfunction	intermittent

Diagnosis / Trigger Conditions

Diagnosis for this issue begins by confirming the presence of DTC C118D01 in the suspension control unit -J775-. Technicians should first inspect the wiring and contacts at the air compressor and compressor electronics -J1135- for any irregularities. If no issues are found with the connections, the repair procedure outlined in TSB 2073034/7 should be followed.

Repair Procedure Summary

If the wiring and contacts are confirmed to be in good condition, the recommended repair for the Audi e-tron air suspension fault involves replacing a specific component. Technicians are instructed to replace the control unit for compressor electronics -J1135-. It is crucial to note that the air compressor itself should not be replaced, as the fault lies with its control unit. This procedure is illustrated in Figure 1 of the TSB, which depicts the compressor electronics control unit -J1135-.

Required Parts

To perform the repair, the following part is required:

• Part Number: 4M0.907.778
• Description: Control unit for compressor electronics J1135 (if necessary)

Additionally, fasteners, bolts, nuts, and screws may be needed as per the repair manual. Only parts listed in this TSB, including superseding part numbers, should be used.

Important Warranty Information

This Technical Service Bulletin 2073034/7 provides guidance for repairs. If your Audi vehicle is outside of its warranty period, this bulletin is informational only, meaning the cost of the repair may not be covered. Warranty claims, identified by Service Number 4316 and Damage Code 0039, must adhere to the Audi Warranty Policies and Procedures Manual and are subject to review and audit by Audi Warranty.

Owner Action

If you are experiencing the "Air suspension: system fault" message or suspect an Audi e-tron air suspension fault with DTC C118D01, it is recommended to schedule an appointment with an authorized Audi service facility. They have the necessary diagnostic tools and training to confirm the issue and perform the correct repair as outlined in TSB 2073034/7.

Source: NHTSA ID 11015758