Friday, August 7, 2020

******** Audi A4 Sedan (8K2) L4-2.0L Turbo (CAEB) Technical DIAGNOSIS AND REPAIR # 401225 Date: 120807


Steering - Highway Speed Steering Wheel Oscillation



40 Steering wheel vibrations



40 12 25



2024687/3



August 7, 2012



Supersedes Technical DIAGNOSIS AND REPAIR Group 40 number 11 - 19 dated December 9, 2011 for reasons listed below.



Affected Vehicles



91



Condition



Customer complaint:



Steering wheel oscillation at highway speeds.



Workshop findings:



^ Steering wheel oscillation, typically at a speed between 70 and 85 mph.



^ TSB 2022179 has been completed and the 1st harmonic of radial force of every tire and wheel assembly is below 18 lbs. at a tire pressure of



2.5bar.



^ Audi original equipment tires are installed on the vehicle.



^ The complaint does not involve vibration in the seat surface or other vehicle components.



Technical Background



Steering wheel vibrations and oscillations are caused by uneven roads, wheel imbalance, impermissibly high radial forces of the tires or other



rotating components on the front of the vehicle.



These ride disturbances are transmitted from the front axle and the steering system to the steering wheel.



Steering wheel oscillations are visible side-to-side movements of the steering wheel spokes and no other vibrations such as in the driver seat or the



vehicle floor are involved. If there are vibrations in the complete vehicle, i.e. in the driver seat and vehicle floor, installing the guide links with



updated bushings will not resolve the concern.



Production Solution



Updated front guide links (aka wishbone links) are equipped with larger fluid-filled bushings that help dampen steering wheel oscillation.



Service



1. Clearly verify steering wheel oscillation. Ensure TSB 2022179 has been completed and Audi original equipment tires are installed on the



vehicle. Each wheel and tire assembly must have less than 18 lbs. of road force variation.



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2. Inspect the front guide links to determine which guide links are installed. The guide link is pictured in Figure 3, point 7.



The updated guide link has a larger fluid-filled bushing that is 75 mm in diameter.



3. If the vehicle is equipped with the original guide links that have the smaller 65 mm bushing, search ETKA by VIN and check the size of the



shouldered hex. nut (6). Example of the ETKA screen shot is pictured in Figure 5, point 6. Determine which guide links are required based on



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the following:



^ For size M12 shouldered hex. nut use 8K0 498 998 guide link conversion kit - M12



^ For size M14 shouldered hex. nut use 8K0 498 998 A guide link conversion kit - M14



Tip: Guide links are available with two different size ball joints which are not interchangeable. Use the shouldered hex. nut (6) size to



determine the correct guide link for the VIN.



4. Install updated guide link conversion kit per the Required Parts and Tools chart below. If the kit part number is not available, guide links can



be ordered by their individual part numbers.



Tip: The bolts and nuts used to install the guide links are one-time-use and must be replaced after each removal.



Warranty



Required Parts and Tools



Additional Information



More information on this system can be found in the following resources:



^ ElsaWeb: Chassis >> Suspension, Wheels, Steering >> Front Suspension >> Specifications >> Fastener Tightening Specification.



The following Technical DIAGNOSIS AND REPAIR(s) will be necessary to complete this procedure:



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^ TSB 2022179, 44 Steering wheel shimmy, vibration and/or oscillation at 55 mph or greater



All parts and service references provided in this TSB are subject to change and/or removal. Always check with your Parts Department and service



manuals for the latest information.