2021 Audi Q7, Q8 Rear Suspension Lowering Not Working TSB

Audi has released Technical Service Bulletin (TSB) 2059841/1 to address an intermittent issue with the rear suspension lowering function in certain 2021 Audi Q7 and Q8 models equipped with adaptive suspension. This bulletin, issued on June 17, 2020, provides guidance for diagnosing and resolving instances where the Audi Q8 rear suspension lowering system is not working as expected.

This TSB is particularly relevant for owners who experience the rear suspension lowering feature becoming unavailable without clear cause. The primary concern is to correctly identify the root of the problem, which often relates to specific diagnostic trouble codes (DTCs) logged in the vehicle's suspension control module.

Symptoms

Owners of affected Audi Q7 and Q8 vehicles may notice that the "rear suspension lowering is intermittently not available." This means the function designed to lower the vehicle's rear for easier loading or access may not respond when activated, or it may only work sporadically.

Fault Codes / DTCs

When the rear suspension lowering system experiences this intermittent issue, workshops may find one or both of the following Diagnostic Trouble Codes (DTCs) stored in the suspension control module, J775 (address word 0074):

Code	Description
C11B515	Button for high load level, interruption/short circuit to positive
C11B615	Button for low load level, interruption/short circuit to positive

These codes indicate a potential issue with the buttons responsible for controlling the rear suspension's high and low load levels.

Technical Background

The technical background for this issue points to unintentional operation of the rear suspension lowering button. If the button, located in the trunk area, is pressed inadvertently while the vehicle is in motion—for example, by objects shifting in the trunk—it can lead to the rear suspension lowering function becoming sporadically unavailable. This is a design characteristic rather than a component failure.

Important Warnings

Audi explicitly states in TSB 2059841/1:

"Do not replace the J775 or the button for the rear suspension lowering or any other component in the vehicle."

This is a crucial warning for owners and technicians, indicating that replacing parts like the J775 suspension control module or the lowering button will not resolve the underlying issue. The problem stems from how the system interprets the button press during driving conditions, not from a faulty component.

Repair Procedure Summary

The resolution for this intermittent Audi Q8 rear suspension lowering issue is straightforward and does not involve component replacement. The procedure outlined in TSB 2059841/1 involves two main steps:

1. Customer Explanation: Technicians are instructed to explain the functionality of the system to the customer. This includes informing them about the possibility of the button being unintentionally operated while driving, which can cause the system to become unavailable.
2. Clear DTCs: The diagnostic trouble codes (DTCs) stored in the suspension control module should be cleared. Once the DTCs are cleared, the vehicle can be released to the owner.

This process emphasizes education and resetting the system rather than hardware repair, reinforcing that the issue is often user-induced rather than a defect.

Owner Action

If you own a 2021 Audi Q7 or Q8 and are experiencing issues with the rear suspension lowering function, especially if it's intermittent, you should contact your authorized Audi dealership. Explain the symptoms you are observing, specifically mentioning that the "rear suspension lowering is intermittently not available." The dealership will be able to diagnose the vehicle, check for DTCs C11B515 and C11B615, and apply the service procedure outlined in TSB 2059841/1. This service is typically covered under warranty if your vehicle meets the specified criteria.